xref: /linux/net/sunrpc/xprtsock.c (revision 2f804aca48322f02a8f44cca540663845ee80fb1)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/net/sunrpc/xprtsock.c
4  *
5  * Client-side transport implementation for sockets.
6  *
7  * TCP callback races fixes (C) 1998 Red Hat
8  * TCP send fixes (C) 1998 Red Hat
9  * TCP NFS related read + write fixes
10  *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
11  *
12  * Rewrite of larges part of the code in order to stabilize TCP stuff.
13  * Fix behaviour when socket buffer is full.
14  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
15  *
16  * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
17  *
18  * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
19  *   <gilles.quillard@bull.net>
20  */
21 
22 #include <linux/types.h>
23 #include <linux/string.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/capability.h>
27 #include <linux/pagemap.h>
28 #include <linux/errno.h>
29 #include <linux/socket.h>
30 #include <linux/in.h>
31 #include <linux/net.h>
32 #include <linux/mm.h>
33 #include <linux/un.h>
34 #include <linux/udp.h>
35 #include <linux/tcp.h>
36 #include <linux/sunrpc/clnt.h>
37 #include <linux/sunrpc/addr.h>
38 #include <linux/sunrpc/sched.h>
39 #include <linux/sunrpc/svcsock.h>
40 #include <linux/sunrpc/xprtsock.h>
41 #include <linux/file.h>
42 #ifdef CONFIG_SUNRPC_BACKCHANNEL
43 #include <linux/sunrpc/bc_xprt.h>
44 #endif
45 
46 #include <net/sock.h>
47 #include <net/checksum.h>
48 #include <net/udp.h>
49 #include <net/tcp.h>
50 #include <linux/bvec.h>
51 #include <linux/highmem.h>
52 #include <linux/uio.h>
53 #include <linux/sched/mm.h>
54 
55 #include <trace/events/sock.h>
56 #include <trace/events/sunrpc.h>
57 
58 #include "socklib.h"
59 #include "sunrpc.h"
60 
61 static void xs_close(struct rpc_xprt *xprt);
62 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock);
63 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
64 		struct socket *sock);
65 
66 /*
67  * xprtsock tunables
68  */
69 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
70 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
71 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
72 
73 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
74 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
75 
76 #define XS_TCP_LINGER_TO	(15U * HZ)
77 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
78 
79 /*
80  * We can register our own files under /proc/sys/sunrpc by
81  * calling register_sysctl() again.  The files in that
82  * directory become the union of all files registered there.
83  *
84  * We simply need to make sure that we don't collide with
85  * someone else's file names!
86  */
87 
88 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
89 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
90 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
91 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
92 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
93 
94 static struct ctl_table_header *sunrpc_table_header;
95 
96 static struct xprt_class xs_local_transport;
97 static struct xprt_class xs_udp_transport;
98 static struct xprt_class xs_tcp_transport;
99 static struct xprt_class xs_bc_tcp_transport;
100 
101 /*
102  * FIXME: changing the UDP slot table size should also resize the UDP
103  *        socket buffers for existing UDP transports
104  */
105 static struct ctl_table xs_tunables_table[] = {
106 	{
107 		.procname	= "udp_slot_table_entries",
108 		.data		= &xprt_udp_slot_table_entries,
109 		.maxlen		= sizeof(unsigned int),
110 		.mode		= 0644,
111 		.proc_handler	= proc_dointvec_minmax,
112 		.extra1		= &min_slot_table_size,
113 		.extra2		= &max_slot_table_size
114 	},
115 	{
116 		.procname	= "tcp_slot_table_entries",
117 		.data		= &xprt_tcp_slot_table_entries,
118 		.maxlen		= sizeof(unsigned int),
119 		.mode		= 0644,
120 		.proc_handler	= proc_dointvec_minmax,
121 		.extra1		= &min_slot_table_size,
122 		.extra2		= &max_slot_table_size
123 	},
124 	{
125 		.procname	= "tcp_max_slot_table_entries",
126 		.data		= &xprt_max_tcp_slot_table_entries,
127 		.maxlen		= sizeof(unsigned int),
128 		.mode		= 0644,
129 		.proc_handler	= proc_dointvec_minmax,
130 		.extra1		= &min_slot_table_size,
131 		.extra2		= &max_tcp_slot_table_limit
132 	},
133 	{
134 		.procname	= "min_resvport",
135 		.data		= &xprt_min_resvport,
136 		.maxlen		= sizeof(unsigned int),
137 		.mode		= 0644,
138 		.proc_handler	= proc_dointvec_minmax,
139 		.extra1		= &xprt_min_resvport_limit,
140 		.extra2		= &xprt_max_resvport_limit
141 	},
142 	{
143 		.procname	= "max_resvport",
144 		.data		= &xprt_max_resvport,
145 		.maxlen		= sizeof(unsigned int),
146 		.mode		= 0644,
147 		.proc_handler	= proc_dointvec_minmax,
148 		.extra1		= &xprt_min_resvport_limit,
149 		.extra2		= &xprt_max_resvport_limit
150 	},
151 	{
152 		.procname	= "tcp_fin_timeout",
153 		.data		= &xs_tcp_fin_timeout,
154 		.maxlen		= sizeof(xs_tcp_fin_timeout),
155 		.mode		= 0644,
156 		.proc_handler	= proc_dointvec_jiffies,
157 	},
158 	{ },
159 };
160 
161 /*
162  * Wait duration for a reply from the RPC portmapper.
163  */
164 #define XS_BIND_TO		(60U * HZ)
165 
166 /*
167  * Delay if a UDP socket connect error occurs.  This is most likely some
168  * kind of resource problem on the local host.
169  */
170 #define XS_UDP_REEST_TO		(2U * HZ)
171 
172 /*
173  * The reestablish timeout allows clients to delay for a bit before attempting
174  * to reconnect to a server that just dropped our connection.
175  *
176  * We implement an exponential backoff when trying to reestablish a TCP
177  * transport connection with the server.  Some servers like to drop a TCP
178  * connection when they are overworked, so we start with a short timeout and
179  * increase over time if the server is down or not responding.
180  */
181 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
182 
183 /*
184  * TCP idle timeout; client drops the transport socket if it is idle
185  * for this long.  Note that we also timeout UDP sockets to prevent
186  * holding port numbers when there is no RPC traffic.
187  */
188 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
189 
190 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
191 # undef  RPC_DEBUG_DATA
192 # define RPCDBG_FACILITY	RPCDBG_TRANS
193 #endif
194 
195 #ifdef RPC_DEBUG_DATA
196 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
197 {
198 	u8 *buf = (u8 *) packet;
199 	int j;
200 
201 	dprintk("RPC:       %s\n", msg);
202 	for (j = 0; j < count && j < 128; j += 4) {
203 		if (!(j & 31)) {
204 			if (j)
205 				dprintk("\n");
206 			dprintk("0x%04x ", j);
207 		}
208 		dprintk("%02x%02x%02x%02x ",
209 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
210 	}
211 	dprintk("\n");
212 }
213 #else
214 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
215 {
216 	/* NOP */
217 }
218 #endif
219 
220 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
221 {
222 	return (struct rpc_xprt *) sk->sk_user_data;
223 }
224 
225 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
226 {
227 	return (struct sockaddr *) &xprt->addr;
228 }
229 
230 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
231 {
232 	return (struct sockaddr_un *) &xprt->addr;
233 }
234 
235 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
236 {
237 	return (struct sockaddr_in *) &xprt->addr;
238 }
239 
240 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
241 {
242 	return (struct sockaddr_in6 *) &xprt->addr;
243 }
244 
245 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
246 {
247 	struct sockaddr *sap = xs_addr(xprt);
248 	struct sockaddr_in6 *sin6;
249 	struct sockaddr_in *sin;
250 	struct sockaddr_un *sun;
251 	char buf[128];
252 
253 	switch (sap->sa_family) {
254 	case AF_LOCAL:
255 		sun = xs_addr_un(xprt);
256 		strscpy(buf, sun->sun_path, sizeof(buf));
257 		xprt->address_strings[RPC_DISPLAY_ADDR] =
258 						kstrdup(buf, GFP_KERNEL);
259 		break;
260 	case AF_INET:
261 		(void)rpc_ntop(sap, buf, sizeof(buf));
262 		xprt->address_strings[RPC_DISPLAY_ADDR] =
263 						kstrdup(buf, GFP_KERNEL);
264 		sin = xs_addr_in(xprt);
265 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
266 		break;
267 	case AF_INET6:
268 		(void)rpc_ntop(sap, buf, sizeof(buf));
269 		xprt->address_strings[RPC_DISPLAY_ADDR] =
270 						kstrdup(buf, GFP_KERNEL);
271 		sin6 = xs_addr_in6(xprt);
272 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
273 		break;
274 	default:
275 		BUG();
276 	}
277 
278 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
279 }
280 
281 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
282 {
283 	struct sockaddr *sap = xs_addr(xprt);
284 	char buf[128];
285 
286 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
287 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
288 
289 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
290 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
291 }
292 
293 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
294 				     const char *protocol,
295 				     const char *netid)
296 {
297 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
298 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
299 	xs_format_common_peer_addresses(xprt);
300 	xs_format_common_peer_ports(xprt);
301 }
302 
303 static void xs_update_peer_port(struct rpc_xprt *xprt)
304 {
305 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
306 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
307 
308 	xs_format_common_peer_ports(xprt);
309 }
310 
311 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
312 {
313 	unsigned int i;
314 
315 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
316 		switch (i) {
317 		case RPC_DISPLAY_PROTO:
318 		case RPC_DISPLAY_NETID:
319 			continue;
320 		default:
321 			kfree(xprt->address_strings[i]);
322 		}
323 }
324 
325 static size_t
326 xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp)
327 {
328 	size_t i,n;
329 
330 	if (!want || !(buf->flags & XDRBUF_SPARSE_PAGES))
331 		return want;
332 	n = (buf->page_base + want + PAGE_SIZE - 1) >> PAGE_SHIFT;
333 	for (i = 0; i < n; i++) {
334 		if (buf->pages[i])
335 			continue;
336 		buf->bvec[i].bv_page = buf->pages[i] = alloc_page(gfp);
337 		if (!buf->pages[i]) {
338 			i *= PAGE_SIZE;
339 			return i > buf->page_base ? i - buf->page_base : 0;
340 		}
341 	}
342 	return want;
343 }
344 
345 static ssize_t
346 xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek)
347 {
348 	ssize_t ret;
349 	if (seek != 0)
350 		iov_iter_advance(&msg->msg_iter, seek);
351 	ret = sock_recvmsg(sock, msg, flags);
352 	return ret > 0 ? ret + seek : ret;
353 }
354 
355 static ssize_t
356 xs_read_kvec(struct socket *sock, struct msghdr *msg, int flags,
357 		struct kvec *kvec, size_t count, size_t seek)
358 {
359 	iov_iter_kvec(&msg->msg_iter, ITER_DEST, kvec, 1, count);
360 	return xs_sock_recvmsg(sock, msg, flags, seek);
361 }
362 
363 static ssize_t
364 xs_read_bvec(struct socket *sock, struct msghdr *msg, int flags,
365 		struct bio_vec *bvec, unsigned long nr, size_t count,
366 		size_t seek)
367 {
368 	iov_iter_bvec(&msg->msg_iter, ITER_DEST, bvec, nr, count);
369 	return xs_sock_recvmsg(sock, msg, flags, seek);
370 }
371 
372 static ssize_t
373 xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
374 		size_t count)
375 {
376 	iov_iter_discard(&msg->msg_iter, ITER_DEST, count);
377 	return sock_recvmsg(sock, msg, flags);
378 }
379 
380 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
381 static void
382 xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
383 {
384 	struct bvec_iter bi = {
385 		.bi_size = count,
386 	};
387 	struct bio_vec bv;
388 
389 	bvec_iter_advance(bvec, &bi, seek & PAGE_MASK);
390 	for_each_bvec(bv, bvec, bi, bi)
391 		flush_dcache_page(bv.bv_page);
392 }
393 #else
394 static inline void
395 xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
396 {
397 }
398 #endif
399 
400 static ssize_t
401 xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags,
402 		struct xdr_buf *buf, size_t count, size_t seek, size_t *read)
403 {
404 	size_t want, seek_init = seek, offset = 0;
405 	ssize_t ret;
406 
407 	want = min_t(size_t, count, buf->head[0].iov_len);
408 	if (seek < want) {
409 		ret = xs_read_kvec(sock, msg, flags, &buf->head[0], want, seek);
410 		if (ret <= 0)
411 			goto sock_err;
412 		offset += ret;
413 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
414 			goto out;
415 		if (ret != want)
416 			goto out;
417 		seek = 0;
418 	} else {
419 		seek -= want;
420 		offset += want;
421 	}
422 
423 	want = xs_alloc_sparse_pages(
424 		buf, min_t(size_t, count - offset, buf->page_len),
425 		GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
426 	if (seek < want) {
427 		ret = xs_read_bvec(sock, msg, flags, buf->bvec,
428 				xdr_buf_pagecount(buf),
429 				want + buf->page_base,
430 				seek + buf->page_base);
431 		if (ret <= 0)
432 			goto sock_err;
433 		xs_flush_bvec(buf->bvec, ret, seek + buf->page_base);
434 		ret -= buf->page_base;
435 		offset += ret;
436 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
437 			goto out;
438 		if (ret != want)
439 			goto out;
440 		seek = 0;
441 	} else {
442 		seek -= want;
443 		offset += want;
444 	}
445 
446 	want = min_t(size_t, count - offset, buf->tail[0].iov_len);
447 	if (seek < want) {
448 		ret = xs_read_kvec(sock, msg, flags, &buf->tail[0], want, seek);
449 		if (ret <= 0)
450 			goto sock_err;
451 		offset += ret;
452 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
453 			goto out;
454 		if (ret != want)
455 			goto out;
456 	} else if (offset < seek_init)
457 		offset = seek_init;
458 	ret = -EMSGSIZE;
459 out:
460 	*read = offset - seek_init;
461 	return ret;
462 sock_err:
463 	offset += seek;
464 	goto out;
465 }
466 
467 static void
468 xs_read_header(struct sock_xprt *transport, struct xdr_buf *buf)
469 {
470 	if (!transport->recv.copied) {
471 		if (buf->head[0].iov_len >= transport->recv.offset)
472 			memcpy(buf->head[0].iov_base,
473 					&transport->recv.xid,
474 					transport->recv.offset);
475 		transport->recv.copied = transport->recv.offset;
476 	}
477 }
478 
479 static bool
480 xs_read_stream_request_done(struct sock_xprt *transport)
481 {
482 	return transport->recv.fraghdr & cpu_to_be32(RPC_LAST_STREAM_FRAGMENT);
483 }
484 
485 static void
486 xs_read_stream_check_eor(struct sock_xprt *transport,
487 		struct msghdr *msg)
488 {
489 	if (xs_read_stream_request_done(transport))
490 		msg->msg_flags |= MSG_EOR;
491 }
492 
493 static ssize_t
494 xs_read_stream_request(struct sock_xprt *transport, struct msghdr *msg,
495 		int flags, struct rpc_rqst *req)
496 {
497 	struct xdr_buf *buf = &req->rq_private_buf;
498 	size_t want, read;
499 	ssize_t ret;
500 
501 	xs_read_header(transport, buf);
502 
503 	want = transport->recv.len - transport->recv.offset;
504 	if (want != 0) {
505 		ret = xs_read_xdr_buf(transport->sock, msg, flags, buf,
506 				transport->recv.copied + want,
507 				transport->recv.copied,
508 				&read);
509 		transport->recv.offset += read;
510 		transport->recv.copied += read;
511 	}
512 
513 	if (transport->recv.offset == transport->recv.len)
514 		xs_read_stream_check_eor(transport, msg);
515 
516 	if (want == 0)
517 		return 0;
518 
519 	switch (ret) {
520 	default:
521 		break;
522 	case -EFAULT:
523 	case -EMSGSIZE:
524 		msg->msg_flags |= MSG_TRUNC;
525 		return read;
526 	case 0:
527 		return -ESHUTDOWN;
528 	}
529 	return ret < 0 ? ret : read;
530 }
531 
532 static size_t
533 xs_read_stream_headersize(bool isfrag)
534 {
535 	if (isfrag)
536 		return sizeof(__be32);
537 	return 3 * sizeof(__be32);
538 }
539 
540 static ssize_t
541 xs_read_stream_header(struct sock_xprt *transport, struct msghdr *msg,
542 		int flags, size_t want, size_t seek)
543 {
544 	struct kvec kvec = {
545 		.iov_base = &transport->recv.fraghdr,
546 		.iov_len = want,
547 	};
548 	return xs_read_kvec(transport->sock, msg, flags, &kvec, want, seek);
549 }
550 
551 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
552 static ssize_t
553 xs_read_stream_call(struct sock_xprt *transport, struct msghdr *msg, int flags)
554 {
555 	struct rpc_xprt *xprt = &transport->xprt;
556 	struct rpc_rqst *req;
557 	ssize_t ret;
558 
559 	/* Is this transport associated with the backchannel? */
560 	if (!xprt->bc_serv)
561 		return -ESHUTDOWN;
562 
563 	/* Look up and lock the request corresponding to the given XID */
564 	req = xprt_lookup_bc_request(xprt, transport->recv.xid);
565 	if (!req) {
566 		printk(KERN_WARNING "Callback slot table overflowed\n");
567 		return -ESHUTDOWN;
568 	}
569 	if (transport->recv.copied && !req->rq_private_buf.len)
570 		return -ESHUTDOWN;
571 
572 	ret = xs_read_stream_request(transport, msg, flags, req);
573 	if (msg->msg_flags & (MSG_EOR|MSG_TRUNC))
574 		xprt_complete_bc_request(req, transport->recv.copied);
575 	else
576 		req->rq_private_buf.len = transport->recv.copied;
577 
578 	return ret;
579 }
580 #else /* CONFIG_SUNRPC_BACKCHANNEL */
581 static ssize_t
582 xs_read_stream_call(struct sock_xprt *transport, struct msghdr *msg, int flags)
583 {
584 	return -ESHUTDOWN;
585 }
586 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
587 
588 static ssize_t
589 xs_read_stream_reply(struct sock_xprt *transport, struct msghdr *msg, int flags)
590 {
591 	struct rpc_xprt *xprt = &transport->xprt;
592 	struct rpc_rqst *req;
593 	ssize_t ret = 0;
594 
595 	/* Look up and lock the request corresponding to the given XID */
596 	spin_lock(&xprt->queue_lock);
597 	req = xprt_lookup_rqst(xprt, transport->recv.xid);
598 	if (!req || (transport->recv.copied && !req->rq_private_buf.len)) {
599 		msg->msg_flags |= MSG_TRUNC;
600 		goto out;
601 	}
602 	xprt_pin_rqst(req);
603 	spin_unlock(&xprt->queue_lock);
604 
605 	ret = xs_read_stream_request(transport, msg, flags, req);
606 
607 	spin_lock(&xprt->queue_lock);
608 	if (msg->msg_flags & (MSG_EOR|MSG_TRUNC))
609 		xprt_complete_rqst(req->rq_task, transport->recv.copied);
610 	else
611 		req->rq_private_buf.len = transport->recv.copied;
612 	xprt_unpin_rqst(req);
613 out:
614 	spin_unlock(&xprt->queue_lock);
615 	return ret;
616 }
617 
618 static ssize_t
619 xs_read_stream(struct sock_xprt *transport, int flags)
620 {
621 	struct msghdr msg = { 0 };
622 	size_t want, read = 0;
623 	ssize_t ret = 0;
624 
625 	if (transport->recv.len == 0) {
626 		want = xs_read_stream_headersize(transport->recv.copied != 0);
627 		ret = xs_read_stream_header(transport, &msg, flags, want,
628 				transport->recv.offset);
629 		if (ret <= 0)
630 			goto out_err;
631 		transport->recv.offset = ret;
632 		if (transport->recv.offset != want)
633 			return transport->recv.offset;
634 		transport->recv.len = be32_to_cpu(transport->recv.fraghdr) &
635 			RPC_FRAGMENT_SIZE_MASK;
636 		transport->recv.offset -= sizeof(transport->recv.fraghdr);
637 		read = ret;
638 	}
639 
640 	switch (be32_to_cpu(transport->recv.calldir)) {
641 	default:
642 		msg.msg_flags |= MSG_TRUNC;
643 		break;
644 	case RPC_CALL:
645 		ret = xs_read_stream_call(transport, &msg, flags);
646 		break;
647 	case RPC_REPLY:
648 		ret = xs_read_stream_reply(transport, &msg, flags);
649 	}
650 	if (msg.msg_flags & MSG_TRUNC) {
651 		transport->recv.calldir = cpu_to_be32(-1);
652 		transport->recv.copied = -1;
653 	}
654 	if (ret < 0)
655 		goto out_err;
656 	read += ret;
657 	if (transport->recv.offset < transport->recv.len) {
658 		if (!(msg.msg_flags & MSG_TRUNC))
659 			return read;
660 		msg.msg_flags = 0;
661 		ret = xs_read_discard(transport->sock, &msg, flags,
662 				transport->recv.len - transport->recv.offset);
663 		if (ret <= 0)
664 			goto out_err;
665 		transport->recv.offset += ret;
666 		read += ret;
667 		if (transport->recv.offset != transport->recv.len)
668 			return read;
669 	}
670 	if (xs_read_stream_request_done(transport)) {
671 		trace_xs_stream_read_request(transport);
672 		transport->recv.copied = 0;
673 	}
674 	transport->recv.offset = 0;
675 	transport->recv.len = 0;
676 	return read;
677 out_err:
678 	return ret != 0 ? ret : -ESHUTDOWN;
679 }
680 
681 static __poll_t xs_poll_socket(struct sock_xprt *transport)
682 {
683 	return transport->sock->ops->poll(transport->file, transport->sock,
684 			NULL);
685 }
686 
687 static bool xs_poll_socket_readable(struct sock_xprt *transport)
688 {
689 	__poll_t events = xs_poll_socket(transport);
690 
691 	return (events & (EPOLLIN | EPOLLRDNORM)) && !(events & EPOLLRDHUP);
692 }
693 
694 static void xs_poll_check_readable(struct sock_xprt *transport)
695 {
696 
697 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
698 	if (!xs_poll_socket_readable(transport))
699 		return;
700 	if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
701 		queue_work(xprtiod_workqueue, &transport->recv_worker);
702 }
703 
704 static void xs_stream_data_receive(struct sock_xprt *transport)
705 {
706 	size_t read = 0;
707 	ssize_t ret = 0;
708 
709 	mutex_lock(&transport->recv_mutex);
710 	if (transport->sock == NULL)
711 		goto out;
712 	for (;;) {
713 		ret = xs_read_stream(transport, MSG_DONTWAIT);
714 		if (ret < 0)
715 			break;
716 		read += ret;
717 		cond_resched();
718 	}
719 	if (ret == -ESHUTDOWN)
720 		kernel_sock_shutdown(transport->sock, SHUT_RDWR);
721 	else
722 		xs_poll_check_readable(transport);
723 out:
724 	mutex_unlock(&transport->recv_mutex);
725 	trace_xs_stream_read_data(&transport->xprt, ret, read);
726 }
727 
728 static void xs_stream_data_receive_workfn(struct work_struct *work)
729 {
730 	struct sock_xprt *transport =
731 		container_of(work, struct sock_xprt, recv_worker);
732 	unsigned int pflags = memalloc_nofs_save();
733 
734 	xs_stream_data_receive(transport);
735 	memalloc_nofs_restore(pflags);
736 }
737 
738 static void
739 xs_stream_reset_connect(struct sock_xprt *transport)
740 {
741 	transport->recv.offset = 0;
742 	transport->recv.len = 0;
743 	transport->recv.copied = 0;
744 	transport->xmit.offset = 0;
745 }
746 
747 static void
748 xs_stream_start_connect(struct sock_xprt *transport)
749 {
750 	transport->xprt.stat.connect_count++;
751 	transport->xprt.stat.connect_start = jiffies;
752 }
753 
754 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
755 
756 /**
757  * xs_nospace - handle transmit was incomplete
758  * @req: pointer to RPC request
759  * @transport: pointer to struct sock_xprt
760  *
761  */
762 static int xs_nospace(struct rpc_rqst *req, struct sock_xprt *transport)
763 {
764 	struct rpc_xprt *xprt = &transport->xprt;
765 	struct sock *sk = transport->inet;
766 	int ret = -EAGAIN;
767 
768 	trace_rpc_socket_nospace(req, transport);
769 
770 	/* Protect against races with write_space */
771 	spin_lock(&xprt->transport_lock);
772 
773 	/* Don't race with disconnect */
774 	if (xprt_connected(xprt)) {
775 		/* wait for more buffer space */
776 		set_bit(XPRT_SOCK_NOSPACE, &transport->sock_state);
777 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
778 		sk->sk_write_pending++;
779 		xprt_wait_for_buffer_space(xprt);
780 	} else
781 		ret = -ENOTCONN;
782 
783 	spin_unlock(&xprt->transport_lock);
784 	return ret;
785 }
786 
787 static int xs_sock_nospace(struct rpc_rqst *req)
788 {
789 	struct sock_xprt *transport =
790 		container_of(req->rq_xprt, struct sock_xprt, xprt);
791 	struct sock *sk = transport->inet;
792 	int ret = -EAGAIN;
793 
794 	lock_sock(sk);
795 	if (!sock_writeable(sk))
796 		ret = xs_nospace(req, transport);
797 	release_sock(sk);
798 	return ret;
799 }
800 
801 static int xs_stream_nospace(struct rpc_rqst *req, bool vm_wait)
802 {
803 	struct sock_xprt *transport =
804 		container_of(req->rq_xprt, struct sock_xprt, xprt);
805 	struct sock *sk = transport->inet;
806 	int ret = -EAGAIN;
807 
808 	if (vm_wait)
809 		return -ENOBUFS;
810 	lock_sock(sk);
811 	if (!sk_stream_memory_free(sk))
812 		ret = xs_nospace(req, transport);
813 	release_sock(sk);
814 	return ret;
815 }
816 
817 static int xs_stream_prepare_request(struct rpc_rqst *req, struct xdr_buf *buf)
818 {
819 	return xdr_alloc_bvec(buf, rpc_task_gfp_mask());
820 }
821 
822 /*
823  * Determine if the previous message in the stream was aborted before it
824  * could complete transmission.
825  */
826 static bool
827 xs_send_request_was_aborted(struct sock_xprt *transport, struct rpc_rqst *req)
828 {
829 	return transport->xmit.offset != 0 && req->rq_bytes_sent == 0;
830 }
831 
832 /*
833  * Return the stream record marker field for a record of length < 2^31-1
834  */
835 static rpc_fraghdr
836 xs_stream_record_marker(struct xdr_buf *xdr)
837 {
838 	if (!xdr->len)
839 		return 0;
840 	return cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | (u32)xdr->len);
841 }
842 
843 /**
844  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
845  * @req: pointer to RPC request
846  *
847  * Return values:
848  *        0:	The request has been sent
849  *   EAGAIN:	The socket was blocked, please call again later to
850  *		complete the request
851  * ENOTCONN:	Caller needs to invoke connect logic then call again
852  *    other:	Some other error occurred, the request was not sent
853  */
854 static int xs_local_send_request(struct rpc_rqst *req)
855 {
856 	struct rpc_xprt *xprt = req->rq_xprt;
857 	struct sock_xprt *transport =
858 				container_of(xprt, struct sock_xprt, xprt);
859 	struct xdr_buf *xdr = &req->rq_snd_buf;
860 	rpc_fraghdr rm = xs_stream_record_marker(xdr);
861 	unsigned int msglen = rm ? req->rq_slen + sizeof(rm) : req->rq_slen;
862 	struct msghdr msg = {
863 		.msg_flags	= XS_SENDMSG_FLAGS,
864 	};
865 	bool vm_wait;
866 	unsigned int sent;
867 	int status;
868 
869 	/* Close the stream if the previous transmission was incomplete */
870 	if (xs_send_request_was_aborted(transport, req)) {
871 		xprt_force_disconnect(xprt);
872 		return -ENOTCONN;
873 	}
874 
875 	xs_pktdump("packet data:",
876 			req->rq_svec->iov_base, req->rq_svec->iov_len);
877 
878 	vm_wait = sk_stream_is_writeable(transport->inet) ? true : false;
879 
880 	req->rq_xtime = ktime_get();
881 	status = xprt_sock_sendmsg(transport->sock, &msg, xdr,
882 				   transport->xmit.offset, rm, &sent);
883 	dprintk("RPC:       %s(%u) = %d\n",
884 			__func__, xdr->len - transport->xmit.offset, status);
885 
886 	if (likely(sent > 0) || status == 0) {
887 		transport->xmit.offset += sent;
888 		req->rq_bytes_sent = transport->xmit.offset;
889 		if (likely(req->rq_bytes_sent >= msglen)) {
890 			req->rq_xmit_bytes_sent += transport->xmit.offset;
891 			transport->xmit.offset = 0;
892 			return 0;
893 		}
894 		status = -EAGAIN;
895 		vm_wait = false;
896 	}
897 
898 	switch (status) {
899 	case -EAGAIN:
900 		status = xs_stream_nospace(req, vm_wait);
901 		break;
902 	default:
903 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
904 			-status);
905 		fallthrough;
906 	case -EPIPE:
907 		xprt_force_disconnect(xprt);
908 		status = -ENOTCONN;
909 	}
910 
911 	return status;
912 }
913 
914 /**
915  * xs_udp_send_request - write an RPC request to a UDP socket
916  * @req: pointer to RPC request
917  *
918  * Return values:
919  *        0:	The request has been sent
920  *   EAGAIN:	The socket was blocked, please call again later to
921  *		complete the request
922  * ENOTCONN:	Caller needs to invoke connect logic then call again
923  *    other:	Some other error occurred, the request was not sent
924  */
925 static int xs_udp_send_request(struct rpc_rqst *req)
926 {
927 	struct rpc_xprt *xprt = req->rq_xprt;
928 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
929 	struct xdr_buf *xdr = &req->rq_snd_buf;
930 	struct msghdr msg = {
931 		.msg_name	= xs_addr(xprt),
932 		.msg_namelen	= xprt->addrlen,
933 		.msg_flags	= XS_SENDMSG_FLAGS,
934 	};
935 	unsigned int sent;
936 	int status;
937 
938 	xs_pktdump("packet data:",
939 				req->rq_svec->iov_base,
940 				req->rq_svec->iov_len);
941 
942 	if (!xprt_bound(xprt))
943 		return -ENOTCONN;
944 
945 	if (!xprt_request_get_cong(xprt, req))
946 		return -EBADSLT;
947 
948 	status = xdr_alloc_bvec(xdr, rpc_task_gfp_mask());
949 	if (status < 0)
950 		return status;
951 	req->rq_xtime = ktime_get();
952 	status = xprt_sock_sendmsg(transport->sock, &msg, xdr, 0, 0, &sent);
953 
954 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
955 			xdr->len, status);
956 
957 	/* firewall is blocking us, don't return -EAGAIN or we end up looping */
958 	if (status == -EPERM)
959 		goto process_status;
960 
961 	if (status == -EAGAIN && sock_writeable(transport->inet))
962 		status = -ENOBUFS;
963 
964 	if (sent > 0 || status == 0) {
965 		req->rq_xmit_bytes_sent += sent;
966 		if (sent >= req->rq_slen)
967 			return 0;
968 		/* Still some bytes left; set up for a retry later. */
969 		status = -EAGAIN;
970 	}
971 
972 process_status:
973 	switch (status) {
974 	case -ENOTSOCK:
975 		status = -ENOTCONN;
976 		/* Should we call xs_close() here? */
977 		break;
978 	case -EAGAIN:
979 		status = xs_sock_nospace(req);
980 		break;
981 	case -ENETUNREACH:
982 	case -ENOBUFS:
983 	case -EPIPE:
984 	case -ECONNREFUSED:
985 	case -EPERM:
986 		/* When the server has died, an ICMP port unreachable message
987 		 * prompts ECONNREFUSED. */
988 		break;
989 	default:
990 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
991 			-status);
992 	}
993 
994 	return status;
995 }
996 
997 /**
998  * xs_tcp_send_request - write an RPC request to a TCP socket
999  * @req: pointer to RPC request
1000  *
1001  * Return values:
1002  *        0:	The request has been sent
1003  *   EAGAIN:	The socket was blocked, please call again later to
1004  *		complete the request
1005  * ENOTCONN:	Caller needs to invoke connect logic then call again
1006  *    other:	Some other error occurred, the request was not sent
1007  *
1008  * XXX: In the case of soft timeouts, should we eventually give up
1009  *	if sendmsg is not able to make progress?
1010  */
1011 static int xs_tcp_send_request(struct rpc_rqst *req)
1012 {
1013 	struct rpc_xprt *xprt = req->rq_xprt;
1014 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1015 	struct xdr_buf *xdr = &req->rq_snd_buf;
1016 	rpc_fraghdr rm = xs_stream_record_marker(xdr);
1017 	unsigned int msglen = rm ? req->rq_slen + sizeof(rm) : req->rq_slen;
1018 	struct msghdr msg = {
1019 		.msg_flags	= XS_SENDMSG_FLAGS,
1020 	};
1021 	bool vm_wait;
1022 	unsigned int sent;
1023 	int status;
1024 
1025 	/* Close the stream if the previous transmission was incomplete */
1026 	if (xs_send_request_was_aborted(transport, req)) {
1027 		if (transport->sock != NULL)
1028 			kernel_sock_shutdown(transport->sock, SHUT_RDWR);
1029 		return -ENOTCONN;
1030 	}
1031 	if (!transport->inet)
1032 		return -ENOTCONN;
1033 
1034 	xs_pktdump("packet data:",
1035 				req->rq_svec->iov_base,
1036 				req->rq_svec->iov_len);
1037 
1038 	if (test_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state))
1039 		xs_tcp_set_socket_timeouts(xprt, transport->sock);
1040 
1041 	xs_set_srcport(transport, transport->sock);
1042 
1043 	/* Continue transmitting the packet/record. We must be careful
1044 	 * to cope with writespace callbacks arriving _after_ we have
1045 	 * called sendmsg(). */
1046 	req->rq_xtime = ktime_get();
1047 	tcp_sock_set_cork(transport->inet, true);
1048 
1049 	vm_wait = sk_stream_is_writeable(transport->inet) ? true : false;
1050 
1051 	do {
1052 		status = xprt_sock_sendmsg(transport->sock, &msg, xdr,
1053 					   transport->xmit.offset, rm, &sent);
1054 
1055 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
1056 				xdr->len - transport->xmit.offset, status);
1057 
1058 		/* If we've sent the entire packet, immediately
1059 		 * reset the count of bytes sent. */
1060 		transport->xmit.offset += sent;
1061 		req->rq_bytes_sent = transport->xmit.offset;
1062 		if (likely(req->rq_bytes_sent >= msglen)) {
1063 			req->rq_xmit_bytes_sent += transport->xmit.offset;
1064 			transport->xmit.offset = 0;
1065 			if (atomic_long_read(&xprt->xmit_queuelen) == 1)
1066 				tcp_sock_set_cork(transport->inet, false);
1067 			return 0;
1068 		}
1069 
1070 		WARN_ON_ONCE(sent == 0 && status == 0);
1071 
1072 		if (sent > 0)
1073 			vm_wait = false;
1074 
1075 	} while (status == 0);
1076 
1077 	switch (status) {
1078 	case -ENOTSOCK:
1079 		status = -ENOTCONN;
1080 		/* Should we call xs_close() here? */
1081 		break;
1082 	case -EAGAIN:
1083 		status = xs_stream_nospace(req, vm_wait);
1084 		break;
1085 	case -ECONNRESET:
1086 	case -ECONNREFUSED:
1087 	case -ENOTCONN:
1088 	case -EADDRINUSE:
1089 	case -ENOBUFS:
1090 	case -EPIPE:
1091 		break;
1092 	default:
1093 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
1094 			-status);
1095 	}
1096 
1097 	return status;
1098 }
1099 
1100 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
1101 {
1102 	transport->old_data_ready = sk->sk_data_ready;
1103 	transport->old_state_change = sk->sk_state_change;
1104 	transport->old_write_space = sk->sk_write_space;
1105 	transport->old_error_report = sk->sk_error_report;
1106 }
1107 
1108 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
1109 {
1110 	sk->sk_data_ready = transport->old_data_ready;
1111 	sk->sk_state_change = transport->old_state_change;
1112 	sk->sk_write_space = transport->old_write_space;
1113 	sk->sk_error_report = transport->old_error_report;
1114 }
1115 
1116 static void xs_sock_reset_state_flags(struct rpc_xprt *xprt)
1117 {
1118 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1119 
1120 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
1121 	clear_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state);
1122 	clear_bit(XPRT_SOCK_WAKE_WRITE, &transport->sock_state);
1123 	clear_bit(XPRT_SOCK_WAKE_DISCONNECT, &transport->sock_state);
1124 	clear_bit(XPRT_SOCK_NOSPACE, &transport->sock_state);
1125 }
1126 
1127 static void xs_run_error_worker(struct sock_xprt *transport, unsigned int nr)
1128 {
1129 	set_bit(nr, &transport->sock_state);
1130 	queue_work(xprtiod_workqueue, &transport->error_worker);
1131 }
1132 
1133 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
1134 {
1135 	xprt->connect_cookie++;
1136 	smp_mb__before_atomic();
1137 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1138 	clear_bit(XPRT_CLOSING, &xprt->state);
1139 	xs_sock_reset_state_flags(xprt);
1140 	smp_mb__after_atomic();
1141 }
1142 
1143 /**
1144  * xs_error_report - callback to handle TCP socket state errors
1145  * @sk: socket
1146  *
1147  * Note: we don't call sock_error() since there may be a rpc_task
1148  * using the socket, and so we don't want to clear sk->sk_err.
1149  */
1150 static void xs_error_report(struct sock *sk)
1151 {
1152 	struct sock_xprt *transport;
1153 	struct rpc_xprt *xprt;
1154 
1155 	if (!(xprt = xprt_from_sock(sk)))
1156 		return;
1157 
1158 	transport = container_of(xprt, struct sock_xprt, xprt);
1159 	transport->xprt_err = -sk->sk_err;
1160 	if (transport->xprt_err == 0)
1161 		return;
1162 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
1163 			xprt, -transport->xprt_err);
1164 	trace_rpc_socket_error(xprt, sk->sk_socket, transport->xprt_err);
1165 
1166 	/* barrier ensures xprt_err is set before XPRT_SOCK_WAKE_ERROR */
1167 	smp_mb__before_atomic();
1168 	xs_run_error_worker(transport, XPRT_SOCK_WAKE_ERROR);
1169 }
1170 
1171 static void xs_reset_transport(struct sock_xprt *transport)
1172 {
1173 	struct socket *sock = transport->sock;
1174 	struct sock *sk = transport->inet;
1175 	struct rpc_xprt *xprt = &transport->xprt;
1176 	struct file *filp = transport->file;
1177 
1178 	if (sk == NULL)
1179 		return;
1180 	/*
1181 	 * Make sure we're calling this in a context from which it is safe
1182 	 * to call __fput_sync(). In practice that means rpciod and the
1183 	 * system workqueue.
1184 	 */
1185 	if (!(current->flags & PF_WQ_WORKER)) {
1186 		WARN_ON_ONCE(1);
1187 		set_bit(XPRT_CLOSE_WAIT, &xprt->state);
1188 		return;
1189 	}
1190 
1191 	if (atomic_read(&transport->xprt.swapper))
1192 		sk_clear_memalloc(sk);
1193 
1194 	kernel_sock_shutdown(sock, SHUT_RDWR);
1195 
1196 	mutex_lock(&transport->recv_mutex);
1197 	lock_sock(sk);
1198 	transport->inet = NULL;
1199 	transport->sock = NULL;
1200 	transport->file = NULL;
1201 
1202 	sk->sk_user_data = NULL;
1203 
1204 	xs_restore_old_callbacks(transport, sk);
1205 	xprt_clear_connected(xprt);
1206 	xs_sock_reset_connection_flags(xprt);
1207 	/* Reset stream record info */
1208 	xs_stream_reset_connect(transport);
1209 	release_sock(sk);
1210 	mutex_unlock(&transport->recv_mutex);
1211 
1212 	trace_rpc_socket_close(xprt, sock);
1213 	__fput_sync(filp);
1214 
1215 	xprt_disconnect_done(xprt);
1216 }
1217 
1218 /**
1219  * xs_close - close a socket
1220  * @xprt: transport
1221  *
1222  * This is used when all requests are complete; ie, no DRC state remains
1223  * on the server we want to save.
1224  *
1225  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
1226  * xs_reset_transport() zeroing the socket from underneath a writer.
1227  */
1228 static void xs_close(struct rpc_xprt *xprt)
1229 {
1230 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1231 
1232 	dprintk("RPC:       xs_close xprt %p\n", xprt);
1233 
1234 	xs_reset_transport(transport);
1235 	xprt->reestablish_timeout = 0;
1236 }
1237 
1238 static void xs_inject_disconnect(struct rpc_xprt *xprt)
1239 {
1240 	dprintk("RPC:       injecting transport disconnect on xprt=%p\n",
1241 		xprt);
1242 	xprt_disconnect_done(xprt);
1243 }
1244 
1245 static void xs_xprt_free(struct rpc_xprt *xprt)
1246 {
1247 	xs_free_peer_addresses(xprt);
1248 	xprt_free(xprt);
1249 }
1250 
1251 /**
1252  * xs_destroy - prepare to shutdown a transport
1253  * @xprt: doomed transport
1254  *
1255  */
1256 static void xs_destroy(struct rpc_xprt *xprt)
1257 {
1258 	struct sock_xprt *transport = container_of(xprt,
1259 			struct sock_xprt, xprt);
1260 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
1261 
1262 	cancel_delayed_work_sync(&transport->connect_worker);
1263 	xs_close(xprt);
1264 	cancel_work_sync(&transport->recv_worker);
1265 	cancel_work_sync(&transport->error_worker);
1266 	xs_xprt_free(xprt);
1267 	module_put(THIS_MODULE);
1268 }
1269 
1270 /**
1271  * xs_udp_data_read_skb - receive callback for UDP sockets
1272  * @xprt: transport
1273  * @sk: socket
1274  * @skb: skbuff
1275  *
1276  */
1277 static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
1278 		struct sock *sk,
1279 		struct sk_buff *skb)
1280 {
1281 	struct rpc_task *task;
1282 	struct rpc_rqst *rovr;
1283 	int repsize, copied;
1284 	u32 _xid;
1285 	__be32 *xp;
1286 
1287 	repsize = skb->len;
1288 	if (repsize < 4) {
1289 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
1290 		return;
1291 	}
1292 
1293 	/* Copy the XID from the skb... */
1294 	xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
1295 	if (xp == NULL)
1296 		return;
1297 
1298 	/* Look up and lock the request corresponding to the given XID */
1299 	spin_lock(&xprt->queue_lock);
1300 	rovr = xprt_lookup_rqst(xprt, *xp);
1301 	if (!rovr)
1302 		goto out_unlock;
1303 	xprt_pin_rqst(rovr);
1304 	xprt_update_rtt(rovr->rq_task);
1305 	spin_unlock(&xprt->queue_lock);
1306 	task = rovr->rq_task;
1307 
1308 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
1309 		copied = repsize;
1310 
1311 	/* Suck it into the iovec, verify checksum if not done by hw. */
1312 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1313 		spin_lock(&xprt->queue_lock);
1314 		__UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
1315 		goto out_unpin;
1316 	}
1317 
1318 
1319 	spin_lock(&xprt->transport_lock);
1320 	xprt_adjust_cwnd(xprt, task, copied);
1321 	spin_unlock(&xprt->transport_lock);
1322 	spin_lock(&xprt->queue_lock);
1323 	xprt_complete_rqst(task, copied);
1324 	__UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);
1325 out_unpin:
1326 	xprt_unpin_rqst(rovr);
1327  out_unlock:
1328 	spin_unlock(&xprt->queue_lock);
1329 }
1330 
1331 static void xs_udp_data_receive(struct sock_xprt *transport)
1332 {
1333 	struct sk_buff *skb;
1334 	struct sock *sk;
1335 	int err;
1336 
1337 	mutex_lock(&transport->recv_mutex);
1338 	sk = transport->inet;
1339 	if (sk == NULL)
1340 		goto out;
1341 	for (;;) {
1342 		skb = skb_recv_udp(sk, MSG_DONTWAIT, &err);
1343 		if (skb == NULL)
1344 			break;
1345 		xs_udp_data_read_skb(&transport->xprt, sk, skb);
1346 		consume_skb(skb);
1347 		cond_resched();
1348 	}
1349 	xs_poll_check_readable(transport);
1350 out:
1351 	mutex_unlock(&transport->recv_mutex);
1352 }
1353 
1354 static void xs_udp_data_receive_workfn(struct work_struct *work)
1355 {
1356 	struct sock_xprt *transport =
1357 		container_of(work, struct sock_xprt, recv_worker);
1358 	unsigned int pflags = memalloc_nofs_save();
1359 
1360 	xs_udp_data_receive(transport);
1361 	memalloc_nofs_restore(pflags);
1362 }
1363 
1364 /**
1365  * xs_data_ready - "data ready" callback for sockets
1366  * @sk: socket with data to read
1367  *
1368  */
1369 static void xs_data_ready(struct sock *sk)
1370 {
1371 	struct rpc_xprt *xprt;
1372 
1373 	trace_sk_data_ready(sk);
1374 
1375 	xprt = xprt_from_sock(sk);
1376 	if (xprt != NULL) {
1377 		struct sock_xprt *transport = container_of(xprt,
1378 				struct sock_xprt, xprt);
1379 
1380 		trace_xs_data_ready(xprt);
1381 
1382 		transport->old_data_ready(sk);
1383 		/* Any data means we had a useful conversation, so
1384 		 * then we don't need to delay the next reconnect
1385 		 */
1386 		if (xprt->reestablish_timeout)
1387 			xprt->reestablish_timeout = 0;
1388 		if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1389 			queue_work(xprtiod_workqueue, &transport->recv_worker);
1390 	}
1391 }
1392 
1393 /*
1394  * Helper function to force a TCP close if the server is sending
1395  * junk and/or it has put us in CLOSE_WAIT
1396  */
1397 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1398 {
1399 	xprt_force_disconnect(xprt);
1400 }
1401 
1402 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1403 static size_t xs_tcp_bc_maxpayload(struct rpc_xprt *xprt)
1404 {
1405 	return PAGE_SIZE;
1406 }
1407 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1408 
1409 /**
1410  * xs_local_state_change - callback to handle AF_LOCAL socket state changes
1411  * @sk: socket whose state has changed
1412  *
1413  */
1414 static void xs_local_state_change(struct sock *sk)
1415 {
1416 	struct rpc_xprt *xprt;
1417 	struct sock_xprt *transport;
1418 
1419 	if (!(xprt = xprt_from_sock(sk)))
1420 		return;
1421 	transport = container_of(xprt, struct sock_xprt, xprt);
1422 	if (sk->sk_shutdown & SHUTDOWN_MASK) {
1423 		clear_bit(XPRT_CONNECTED, &xprt->state);
1424 		/* Trigger the socket release */
1425 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1426 	}
1427 }
1428 
1429 /**
1430  * xs_tcp_state_change - callback to handle TCP socket state changes
1431  * @sk: socket whose state has changed
1432  *
1433  */
1434 static void xs_tcp_state_change(struct sock *sk)
1435 {
1436 	struct rpc_xprt *xprt;
1437 	struct sock_xprt *transport;
1438 
1439 	if (!(xprt = xprt_from_sock(sk)))
1440 		return;
1441 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1442 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1443 			sk->sk_state, xprt_connected(xprt),
1444 			sock_flag(sk, SOCK_DEAD),
1445 			sock_flag(sk, SOCK_ZAPPED),
1446 			sk->sk_shutdown);
1447 
1448 	transport = container_of(xprt, struct sock_xprt, xprt);
1449 	trace_rpc_socket_state_change(xprt, sk->sk_socket);
1450 	switch (sk->sk_state) {
1451 	case TCP_ESTABLISHED:
1452 		if (!xprt_test_and_set_connected(xprt)) {
1453 			xprt->connect_cookie++;
1454 			clear_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
1455 			xprt_clear_connecting(xprt);
1456 
1457 			xprt->stat.connect_count++;
1458 			xprt->stat.connect_time += (long)jiffies -
1459 						   xprt->stat.connect_start;
1460 			xs_run_error_worker(transport, XPRT_SOCK_WAKE_PENDING);
1461 		}
1462 		break;
1463 	case TCP_FIN_WAIT1:
1464 		/* The client initiated a shutdown of the socket */
1465 		xprt->connect_cookie++;
1466 		xprt->reestablish_timeout = 0;
1467 		set_bit(XPRT_CLOSING, &xprt->state);
1468 		smp_mb__before_atomic();
1469 		clear_bit(XPRT_CONNECTED, &xprt->state);
1470 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1471 		smp_mb__after_atomic();
1472 		break;
1473 	case TCP_CLOSE_WAIT:
1474 		/* The server initiated a shutdown of the socket */
1475 		xprt->connect_cookie++;
1476 		clear_bit(XPRT_CONNECTED, &xprt->state);
1477 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1478 		fallthrough;
1479 	case TCP_CLOSING:
1480 		/*
1481 		 * If the server closed down the connection, make sure that
1482 		 * we back off before reconnecting
1483 		 */
1484 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1485 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1486 		break;
1487 	case TCP_LAST_ACK:
1488 		set_bit(XPRT_CLOSING, &xprt->state);
1489 		smp_mb__before_atomic();
1490 		clear_bit(XPRT_CONNECTED, &xprt->state);
1491 		smp_mb__after_atomic();
1492 		break;
1493 	case TCP_CLOSE:
1494 		if (test_and_clear_bit(XPRT_SOCK_CONNECTING,
1495 					&transport->sock_state))
1496 			xprt_clear_connecting(xprt);
1497 		clear_bit(XPRT_CLOSING, &xprt->state);
1498 		/* Trigger the socket release */
1499 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1500 	}
1501 }
1502 
1503 static void xs_write_space(struct sock *sk)
1504 {
1505 	struct sock_xprt *transport;
1506 	struct rpc_xprt *xprt;
1507 
1508 	if (!sk->sk_socket)
1509 		return;
1510 	clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1511 
1512 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1513 		return;
1514 	transport = container_of(xprt, struct sock_xprt, xprt);
1515 	if (!test_and_clear_bit(XPRT_SOCK_NOSPACE, &transport->sock_state))
1516 		return;
1517 	xs_run_error_worker(transport, XPRT_SOCK_WAKE_WRITE);
1518 	sk->sk_write_pending--;
1519 }
1520 
1521 /**
1522  * xs_udp_write_space - callback invoked when socket buffer space
1523  *                             becomes available
1524  * @sk: socket whose state has changed
1525  *
1526  * Called when more output buffer space is available for this socket.
1527  * We try not to wake our writers until they can make "significant"
1528  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1529  * with a bunch of small requests.
1530  */
1531 static void xs_udp_write_space(struct sock *sk)
1532 {
1533 	/* from net/core/sock.c:sock_def_write_space */
1534 	if (sock_writeable(sk))
1535 		xs_write_space(sk);
1536 }
1537 
1538 /**
1539  * xs_tcp_write_space - callback invoked when socket buffer space
1540  *                             becomes available
1541  * @sk: socket whose state has changed
1542  *
1543  * Called when more output buffer space is available for this socket.
1544  * We try not to wake our writers until they can make "significant"
1545  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1546  * with a bunch of small requests.
1547  */
1548 static void xs_tcp_write_space(struct sock *sk)
1549 {
1550 	/* from net/core/stream.c:sk_stream_write_space */
1551 	if (sk_stream_is_writeable(sk))
1552 		xs_write_space(sk);
1553 }
1554 
1555 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1556 {
1557 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1558 	struct sock *sk = transport->inet;
1559 
1560 	if (transport->rcvsize) {
1561 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1562 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1563 	}
1564 	if (transport->sndsize) {
1565 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1566 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1567 		sk->sk_write_space(sk);
1568 	}
1569 }
1570 
1571 /**
1572  * xs_udp_set_buffer_size - set send and receive limits
1573  * @xprt: generic transport
1574  * @sndsize: requested size of send buffer, in bytes
1575  * @rcvsize: requested size of receive buffer, in bytes
1576  *
1577  * Set socket send and receive buffer size limits.
1578  */
1579 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1580 {
1581 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1582 
1583 	transport->sndsize = 0;
1584 	if (sndsize)
1585 		transport->sndsize = sndsize + 1024;
1586 	transport->rcvsize = 0;
1587 	if (rcvsize)
1588 		transport->rcvsize = rcvsize + 1024;
1589 
1590 	xs_udp_do_set_buffer_size(xprt);
1591 }
1592 
1593 /**
1594  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1595  * @xprt: controlling transport
1596  * @task: task that timed out
1597  *
1598  * Adjust the congestion window after a retransmit timeout has occurred.
1599  */
1600 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1601 {
1602 	spin_lock(&xprt->transport_lock);
1603 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1604 	spin_unlock(&xprt->transport_lock);
1605 }
1606 
1607 static int xs_get_random_port(void)
1608 {
1609 	unsigned short min = xprt_min_resvport, max = xprt_max_resvport;
1610 	unsigned short range;
1611 	unsigned short rand;
1612 
1613 	if (max < min)
1614 		return -EADDRINUSE;
1615 	range = max - min + 1;
1616 	rand = get_random_u32_below(range);
1617 	return rand + min;
1618 }
1619 
1620 static unsigned short xs_sock_getport(struct socket *sock)
1621 {
1622 	struct sockaddr_storage buf;
1623 	unsigned short port = 0;
1624 
1625 	if (kernel_getsockname(sock, (struct sockaddr *)&buf) < 0)
1626 		goto out;
1627 	switch (buf.ss_family) {
1628 	case AF_INET6:
1629 		port = ntohs(((struct sockaddr_in6 *)&buf)->sin6_port);
1630 		break;
1631 	case AF_INET:
1632 		port = ntohs(((struct sockaddr_in *)&buf)->sin_port);
1633 	}
1634 out:
1635 	return port;
1636 }
1637 
1638 /**
1639  * xs_set_port - reset the port number in the remote endpoint address
1640  * @xprt: generic transport
1641  * @port: new port number
1642  *
1643  */
1644 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1645 {
1646 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1647 
1648 	rpc_set_port(xs_addr(xprt), port);
1649 	xs_update_peer_port(xprt);
1650 }
1651 
1652 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock)
1653 {
1654 	if (transport->srcport == 0 && transport->xprt.reuseport)
1655 		transport->srcport = xs_sock_getport(sock);
1656 }
1657 
1658 static int xs_get_srcport(struct sock_xprt *transport)
1659 {
1660 	int port = transport->srcport;
1661 
1662 	if (port == 0 && transport->xprt.resvport)
1663 		port = xs_get_random_port();
1664 	return port;
1665 }
1666 
1667 static unsigned short xs_sock_srcport(struct rpc_xprt *xprt)
1668 {
1669 	struct sock_xprt *sock = container_of(xprt, struct sock_xprt, xprt);
1670 	unsigned short ret = 0;
1671 	mutex_lock(&sock->recv_mutex);
1672 	if (sock->sock)
1673 		ret = xs_sock_getport(sock->sock);
1674 	mutex_unlock(&sock->recv_mutex);
1675 	return ret;
1676 }
1677 
1678 static int xs_sock_srcaddr(struct rpc_xprt *xprt, char *buf, size_t buflen)
1679 {
1680 	struct sock_xprt *sock = container_of(xprt, struct sock_xprt, xprt);
1681 	union {
1682 		struct sockaddr sa;
1683 		struct sockaddr_storage st;
1684 	} saddr;
1685 	int ret = -ENOTCONN;
1686 
1687 	mutex_lock(&sock->recv_mutex);
1688 	if (sock->sock) {
1689 		ret = kernel_getsockname(sock->sock, &saddr.sa);
1690 		if (ret >= 0)
1691 			ret = snprintf(buf, buflen, "%pISc", &saddr.sa);
1692 	}
1693 	mutex_unlock(&sock->recv_mutex);
1694 	return ret;
1695 }
1696 
1697 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1698 {
1699 	if (transport->srcport != 0)
1700 		transport->srcport = 0;
1701 	if (!transport->xprt.resvport)
1702 		return 0;
1703 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1704 		return xprt_max_resvport;
1705 	return --port;
1706 }
1707 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1708 {
1709 	struct sockaddr_storage myaddr;
1710 	int err, nloop = 0;
1711 	int port = xs_get_srcport(transport);
1712 	unsigned short last;
1713 
1714 	/*
1715 	 * If we are asking for any ephemeral port (i.e. port == 0 &&
1716 	 * transport->xprt.resvport == 0), don't bind.  Let the local
1717 	 * port selection happen implicitly when the socket is used
1718 	 * (for example at connect time).
1719 	 *
1720 	 * This ensures that we can continue to establish TCP
1721 	 * connections even when all local ephemeral ports are already
1722 	 * a part of some TCP connection.  This makes no difference
1723 	 * for UDP sockets, but also doesn't harm them.
1724 	 *
1725 	 * If we're asking for any reserved port (i.e. port == 0 &&
1726 	 * transport->xprt.resvport == 1) xs_get_srcport above will
1727 	 * ensure that port is non-zero and we will bind as needed.
1728 	 */
1729 	if (port <= 0)
1730 		return port;
1731 
1732 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1733 	do {
1734 		rpc_set_port((struct sockaddr *)&myaddr, port);
1735 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1736 				transport->xprt.addrlen);
1737 		if (err == 0) {
1738 			if (transport->xprt.reuseport)
1739 				transport->srcport = port;
1740 			break;
1741 		}
1742 		last = port;
1743 		port = xs_next_srcport(transport, port);
1744 		if (port > last)
1745 			nloop++;
1746 	} while (err == -EADDRINUSE && nloop != 2);
1747 
1748 	if (myaddr.ss_family == AF_INET)
1749 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1750 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1751 				port, err ? "failed" : "ok", err);
1752 	else
1753 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1754 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1755 				port, err ? "failed" : "ok", err);
1756 	return err;
1757 }
1758 
1759 /*
1760  * We don't support autobind on AF_LOCAL sockets
1761  */
1762 static void xs_local_rpcbind(struct rpc_task *task)
1763 {
1764 	xprt_set_bound(task->tk_xprt);
1765 }
1766 
1767 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1768 {
1769 }
1770 
1771 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1772 static struct lock_class_key xs_key[3];
1773 static struct lock_class_key xs_slock_key[3];
1774 
1775 static inline void xs_reclassify_socketu(struct socket *sock)
1776 {
1777 	struct sock *sk = sock->sk;
1778 
1779 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1780 		&xs_slock_key[0], "sk_lock-AF_LOCAL-RPC", &xs_key[0]);
1781 }
1782 
1783 static inline void xs_reclassify_socket4(struct socket *sock)
1784 {
1785 	struct sock *sk = sock->sk;
1786 
1787 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1788 		&xs_slock_key[1], "sk_lock-AF_INET-RPC", &xs_key[1]);
1789 }
1790 
1791 static inline void xs_reclassify_socket6(struct socket *sock)
1792 {
1793 	struct sock *sk = sock->sk;
1794 
1795 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1796 		&xs_slock_key[2], "sk_lock-AF_INET6-RPC", &xs_key[2]);
1797 }
1798 
1799 static inline void xs_reclassify_socket(int family, struct socket *sock)
1800 {
1801 	if (WARN_ON_ONCE(!sock_allow_reclassification(sock->sk)))
1802 		return;
1803 
1804 	switch (family) {
1805 	case AF_LOCAL:
1806 		xs_reclassify_socketu(sock);
1807 		break;
1808 	case AF_INET:
1809 		xs_reclassify_socket4(sock);
1810 		break;
1811 	case AF_INET6:
1812 		xs_reclassify_socket6(sock);
1813 		break;
1814 	}
1815 }
1816 #else
1817 static inline void xs_reclassify_socket(int family, struct socket *sock)
1818 {
1819 }
1820 #endif
1821 
1822 static void xs_dummy_setup_socket(struct work_struct *work)
1823 {
1824 }
1825 
1826 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1827 		struct sock_xprt *transport, int family, int type,
1828 		int protocol, bool reuseport)
1829 {
1830 	struct file *filp;
1831 	struct socket *sock;
1832 	int err;
1833 
1834 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1835 	if (err < 0) {
1836 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1837 				protocol, -err);
1838 		goto out;
1839 	}
1840 	xs_reclassify_socket(family, sock);
1841 
1842 	if (reuseport)
1843 		sock_set_reuseport(sock->sk);
1844 
1845 	err = xs_bind(transport, sock);
1846 	if (err) {
1847 		sock_release(sock);
1848 		goto out;
1849 	}
1850 
1851 	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
1852 	if (IS_ERR(filp))
1853 		return ERR_CAST(filp);
1854 	transport->file = filp;
1855 
1856 	return sock;
1857 out:
1858 	return ERR_PTR(err);
1859 }
1860 
1861 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1862 				      struct socket *sock)
1863 {
1864 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1865 									xprt);
1866 
1867 	if (!transport->inet) {
1868 		struct sock *sk = sock->sk;
1869 
1870 		lock_sock(sk);
1871 
1872 		xs_save_old_callbacks(transport, sk);
1873 
1874 		sk->sk_user_data = xprt;
1875 		sk->sk_data_ready = xs_data_ready;
1876 		sk->sk_write_space = xs_udp_write_space;
1877 		sk->sk_state_change = xs_local_state_change;
1878 		sk->sk_error_report = xs_error_report;
1879 		sk->sk_use_task_frag = false;
1880 
1881 		xprt_clear_connected(xprt);
1882 
1883 		/* Reset to new socket */
1884 		transport->sock = sock;
1885 		transport->inet = sk;
1886 
1887 		release_sock(sk);
1888 	}
1889 
1890 	xs_stream_start_connect(transport);
1891 
1892 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
1893 }
1894 
1895 /**
1896  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
1897  * @transport: socket transport to connect
1898  */
1899 static int xs_local_setup_socket(struct sock_xprt *transport)
1900 {
1901 	struct rpc_xprt *xprt = &transport->xprt;
1902 	struct file *filp;
1903 	struct socket *sock;
1904 	int status;
1905 
1906 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
1907 					SOCK_STREAM, 0, &sock, 1);
1908 	if (status < 0) {
1909 		dprintk("RPC:       can't create AF_LOCAL "
1910 			"transport socket (%d).\n", -status);
1911 		goto out;
1912 	}
1913 	xs_reclassify_socket(AF_LOCAL, sock);
1914 
1915 	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
1916 	if (IS_ERR(filp)) {
1917 		status = PTR_ERR(filp);
1918 		goto out;
1919 	}
1920 	transport->file = filp;
1921 
1922 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
1923 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1924 
1925 	status = xs_local_finish_connecting(xprt, sock);
1926 	trace_rpc_socket_connect(xprt, sock, status);
1927 	switch (status) {
1928 	case 0:
1929 		dprintk("RPC:       xprt %p connected to %s\n",
1930 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1931 		xprt->stat.connect_count++;
1932 		xprt->stat.connect_time += (long)jiffies -
1933 					   xprt->stat.connect_start;
1934 		xprt_set_connected(xprt);
1935 		break;
1936 	case -ENOBUFS:
1937 		break;
1938 	case -ENOENT:
1939 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
1940 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1941 		break;
1942 	case -ECONNREFUSED:
1943 		dprintk("RPC:       xprt %p: connection refused for %s\n",
1944 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1945 		break;
1946 	default:
1947 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
1948 				__func__, -status,
1949 				xprt->address_strings[RPC_DISPLAY_ADDR]);
1950 	}
1951 
1952 out:
1953 	xprt_clear_connecting(xprt);
1954 	xprt_wake_pending_tasks(xprt, status);
1955 	return status;
1956 }
1957 
1958 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
1959 {
1960 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1961 	int ret;
1962 
1963 	if (transport->file)
1964 		goto force_disconnect;
1965 
1966 	if (RPC_IS_ASYNC(task)) {
1967 		/*
1968 		 * We want the AF_LOCAL connect to be resolved in the
1969 		 * filesystem namespace of the process making the rpc
1970 		 * call.  Thus we connect synchronously.
1971 		 *
1972 		 * If we want to support asynchronous AF_LOCAL calls,
1973 		 * we'll need to figure out how to pass a namespace to
1974 		 * connect.
1975 		 */
1976 		rpc_task_set_rpc_status(task, -ENOTCONN);
1977 		goto out_wake;
1978 	}
1979 	ret = xs_local_setup_socket(transport);
1980 	if (ret && !RPC_IS_SOFTCONN(task))
1981 		msleep_interruptible(15000);
1982 	return;
1983 force_disconnect:
1984 	xprt_force_disconnect(xprt);
1985 out_wake:
1986 	xprt_clear_connecting(xprt);
1987 	xprt_wake_pending_tasks(xprt, -ENOTCONN);
1988 }
1989 
1990 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
1991 /*
1992  * Note that this should be called with XPRT_LOCKED held, or recv_mutex
1993  * held, or when we otherwise know that we have exclusive access to the
1994  * socket, to guard against races with xs_reset_transport.
1995  */
1996 static void xs_set_memalloc(struct rpc_xprt *xprt)
1997 {
1998 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1999 			xprt);
2000 
2001 	/*
2002 	 * If there's no sock, then we have nothing to set. The
2003 	 * reconnecting process will get it for us.
2004 	 */
2005 	if (!transport->inet)
2006 		return;
2007 	if (atomic_read(&xprt->swapper))
2008 		sk_set_memalloc(transport->inet);
2009 }
2010 
2011 /**
2012  * xs_enable_swap - Tag this transport as being used for swap.
2013  * @xprt: transport to tag
2014  *
2015  * Take a reference to this transport on behalf of the rpc_clnt, and
2016  * optionally mark it for swapping if it wasn't already.
2017  */
2018 static int
2019 xs_enable_swap(struct rpc_xprt *xprt)
2020 {
2021 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2022 
2023 	mutex_lock(&xs->recv_mutex);
2024 	if (atomic_inc_return(&xprt->swapper) == 1 &&
2025 	    xs->inet)
2026 		sk_set_memalloc(xs->inet);
2027 	mutex_unlock(&xs->recv_mutex);
2028 	return 0;
2029 }
2030 
2031 /**
2032  * xs_disable_swap - Untag this transport as being used for swap.
2033  * @xprt: transport to tag
2034  *
2035  * Drop a "swapper" reference to this xprt on behalf of the rpc_clnt. If the
2036  * swapper refcount goes to 0, untag the socket as a memalloc socket.
2037  */
2038 static void
2039 xs_disable_swap(struct rpc_xprt *xprt)
2040 {
2041 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2042 
2043 	mutex_lock(&xs->recv_mutex);
2044 	if (atomic_dec_and_test(&xprt->swapper) &&
2045 	    xs->inet)
2046 		sk_clear_memalloc(xs->inet);
2047 	mutex_unlock(&xs->recv_mutex);
2048 }
2049 #else
2050 static void xs_set_memalloc(struct rpc_xprt *xprt)
2051 {
2052 }
2053 
2054 static int
2055 xs_enable_swap(struct rpc_xprt *xprt)
2056 {
2057 	return -EINVAL;
2058 }
2059 
2060 static void
2061 xs_disable_swap(struct rpc_xprt *xprt)
2062 {
2063 }
2064 #endif
2065 
2066 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2067 {
2068 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2069 
2070 	if (!transport->inet) {
2071 		struct sock *sk = sock->sk;
2072 
2073 		lock_sock(sk);
2074 
2075 		xs_save_old_callbacks(transport, sk);
2076 
2077 		sk->sk_user_data = xprt;
2078 		sk->sk_data_ready = xs_data_ready;
2079 		sk->sk_write_space = xs_udp_write_space;
2080 		sk->sk_use_task_frag = false;
2081 
2082 		xprt_set_connected(xprt);
2083 
2084 		/* Reset to new socket */
2085 		transport->sock = sock;
2086 		transport->inet = sk;
2087 
2088 		xs_set_memalloc(xprt);
2089 
2090 		release_sock(sk);
2091 	}
2092 	xs_udp_do_set_buffer_size(xprt);
2093 
2094 	xprt->stat.connect_start = jiffies;
2095 }
2096 
2097 static void xs_udp_setup_socket(struct work_struct *work)
2098 {
2099 	struct sock_xprt *transport =
2100 		container_of(work, struct sock_xprt, connect_worker.work);
2101 	struct rpc_xprt *xprt = &transport->xprt;
2102 	struct socket *sock;
2103 	int status = -EIO;
2104 	unsigned int pflags = current->flags;
2105 
2106 	if (atomic_read(&xprt->swapper))
2107 		current->flags |= PF_MEMALLOC;
2108 	sock = xs_create_sock(xprt, transport,
2109 			xs_addr(xprt)->sa_family, SOCK_DGRAM,
2110 			IPPROTO_UDP, false);
2111 	if (IS_ERR(sock))
2112 		goto out;
2113 
2114 	dprintk("RPC:       worker connecting xprt %p via %s to "
2115 				"%s (port %s)\n", xprt,
2116 			xprt->address_strings[RPC_DISPLAY_PROTO],
2117 			xprt->address_strings[RPC_DISPLAY_ADDR],
2118 			xprt->address_strings[RPC_DISPLAY_PORT]);
2119 
2120 	xs_udp_finish_connecting(xprt, sock);
2121 	trace_rpc_socket_connect(xprt, sock, 0);
2122 	status = 0;
2123 out:
2124 	xprt_clear_connecting(xprt);
2125 	xprt_unlock_connect(xprt, transport);
2126 	xprt_wake_pending_tasks(xprt, status);
2127 	current_restore_flags(pflags, PF_MEMALLOC);
2128 }
2129 
2130 /**
2131  * xs_tcp_shutdown - gracefully shut down a TCP socket
2132  * @xprt: transport
2133  *
2134  * Initiates a graceful shutdown of the TCP socket by calling the
2135  * equivalent of shutdown(SHUT_RDWR);
2136  */
2137 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
2138 {
2139 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2140 	struct socket *sock = transport->sock;
2141 	int skst = transport->inet ? transport->inet->sk_state : TCP_CLOSE;
2142 
2143 	if (sock == NULL)
2144 		return;
2145 	if (!xprt->reuseport) {
2146 		xs_close(xprt);
2147 		return;
2148 	}
2149 	switch (skst) {
2150 	case TCP_FIN_WAIT1:
2151 	case TCP_FIN_WAIT2:
2152 	case TCP_LAST_ACK:
2153 		break;
2154 	case TCP_ESTABLISHED:
2155 	case TCP_CLOSE_WAIT:
2156 		kernel_sock_shutdown(sock, SHUT_RDWR);
2157 		trace_rpc_socket_shutdown(xprt, sock);
2158 		break;
2159 	default:
2160 		xs_reset_transport(transport);
2161 	}
2162 }
2163 
2164 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
2165 		struct socket *sock)
2166 {
2167 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2168 	unsigned int keepidle;
2169 	unsigned int keepcnt;
2170 	unsigned int timeo;
2171 
2172 	spin_lock(&xprt->transport_lock);
2173 	keepidle = DIV_ROUND_UP(xprt->timeout->to_initval, HZ);
2174 	keepcnt = xprt->timeout->to_retries + 1;
2175 	timeo = jiffies_to_msecs(xprt->timeout->to_initval) *
2176 		(xprt->timeout->to_retries + 1);
2177 	clear_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2178 	spin_unlock(&xprt->transport_lock);
2179 
2180 	/* TCP Keepalive options */
2181 	sock_set_keepalive(sock->sk);
2182 	tcp_sock_set_keepidle(sock->sk, keepidle);
2183 	tcp_sock_set_keepintvl(sock->sk, keepidle);
2184 	tcp_sock_set_keepcnt(sock->sk, keepcnt);
2185 
2186 	/* TCP user timeout (see RFC5482) */
2187 	tcp_sock_set_user_timeout(sock->sk, timeo);
2188 }
2189 
2190 static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
2191 		unsigned long connect_timeout,
2192 		unsigned long reconnect_timeout)
2193 {
2194 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2195 	struct rpc_timeout to;
2196 	unsigned long initval;
2197 
2198 	spin_lock(&xprt->transport_lock);
2199 	if (reconnect_timeout < xprt->max_reconnect_timeout)
2200 		xprt->max_reconnect_timeout = reconnect_timeout;
2201 	if (connect_timeout < xprt->connect_timeout) {
2202 		memcpy(&to, xprt->timeout, sizeof(to));
2203 		initval = DIV_ROUND_UP(connect_timeout, to.to_retries + 1);
2204 		/* Arbitrary lower limit */
2205 		if (initval <  XS_TCP_INIT_REEST_TO << 1)
2206 			initval = XS_TCP_INIT_REEST_TO << 1;
2207 		to.to_initval = initval;
2208 		to.to_maxval = initval;
2209 		memcpy(&transport->tcp_timeout, &to,
2210 				sizeof(transport->tcp_timeout));
2211 		xprt->timeout = &transport->tcp_timeout;
2212 		xprt->connect_timeout = connect_timeout;
2213 	}
2214 	set_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2215 	spin_unlock(&xprt->transport_lock);
2216 }
2217 
2218 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2219 {
2220 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2221 
2222 	if (!transport->inet) {
2223 		struct sock *sk = sock->sk;
2224 
2225 		/* Avoid temporary address, they are bad for long-lived
2226 		 * connections such as NFS mounts.
2227 		 * RFC4941, section 3.6 suggests that:
2228 		 *    Individual applications, which have specific
2229 		 *    knowledge about the normal duration of connections,
2230 		 *    MAY override this as appropriate.
2231 		 */
2232 		if (xs_addr(xprt)->sa_family == PF_INET6) {
2233 			ip6_sock_set_addr_preferences(sk,
2234 				IPV6_PREFER_SRC_PUBLIC);
2235 		}
2236 
2237 		xs_tcp_set_socket_timeouts(xprt, sock);
2238 		tcp_sock_set_nodelay(sk);
2239 
2240 		lock_sock(sk);
2241 
2242 		xs_save_old_callbacks(transport, sk);
2243 
2244 		sk->sk_user_data = xprt;
2245 		sk->sk_data_ready = xs_data_ready;
2246 		sk->sk_state_change = xs_tcp_state_change;
2247 		sk->sk_write_space = xs_tcp_write_space;
2248 		sk->sk_error_report = xs_error_report;
2249 		sk->sk_use_task_frag = false;
2250 
2251 		/* socket options */
2252 		sock_reset_flag(sk, SOCK_LINGER);
2253 
2254 		xprt_clear_connected(xprt);
2255 
2256 		/* Reset to new socket */
2257 		transport->sock = sock;
2258 		transport->inet = sk;
2259 
2260 		release_sock(sk);
2261 	}
2262 
2263 	if (!xprt_bound(xprt))
2264 		return -ENOTCONN;
2265 
2266 	xs_set_memalloc(xprt);
2267 
2268 	xs_stream_start_connect(transport);
2269 
2270 	/* Tell the socket layer to start connecting... */
2271 	set_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
2272 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2273 }
2274 
2275 /**
2276  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2277  * @work: queued work item
2278  *
2279  * Invoked by a work queue tasklet.
2280  */
2281 static void xs_tcp_setup_socket(struct work_struct *work)
2282 {
2283 	struct sock_xprt *transport =
2284 		container_of(work, struct sock_xprt, connect_worker.work);
2285 	struct socket *sock = transport->sock;
2286 	struct rpc_xprt *xprt = &transport->xprt;
2287 	int status;
2288 	unsigned int pflags = current->flags;
2289 
2290 	if (atomic_read(&xprt->swapper))
2291 		current->flags |= PF_MEMALLOC;
2292 
2293 	if (xprt_connected(xprt))
2294 		goto out;
2295 	if (test_and_clear_bit(XPRT_SOCK_CONNECT_SENT,
2296 			       &transport->sock_state) ||
2297 	    !sock) {
2298 		xs_reset_transport(transport);
2299 		sock = xs_create_sock(xprt, transport, xs_addr(xprt)->sa_family,
2300 				      SOCK_STREAM, IPPROTO_TCP, true);
2301 		if (IS_ERR(sock)) {
2302 			xprt_wake_pending_tasks(xprt, PTR_ERR(sock));
2303 			goto out;
2304 		}
2305 	}
2306 
2307 	dprintk("RPC:       worker connecting xprt %p via %s to "
2308 				"%s (port %s)\n", xprt,
2309 			xprt->address_strings[RPC_DISPLAY_PROTO],
2310 			xprt->address_strings[RPC_DISPLAY_ADDR],
2311 			xprt->address_strings[RPC_DISPLAY_PORT]);
2312 
2313 	status = xs_tcp_finish_connecting(xprt, sock);
2314 	trace_rpc_socket_connect(xprt, sock, status);
2315 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2316 			xprt, -status, xprt_connected(xprt),
2317 			sock->sk->sk_state);
2318 	switch (status) {
2319 	case 0:
2320 	case -EINPROGRESS:
2321 		/* SYN_SENT! */
2322 		set_bit(XPRT_SOCK_CONNECT_SENT, &transport->sock_state);
2323 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2324 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2325 		fallthrough;
2326 	case -EALREADY:
2327 		goto out_unlock;
2328 	case -EADDRNOTAVAIL:
2329 		/* Source port number is unavailable. Try a new one! */
2330 		transport->srcport = 0;
2331 		status = -EAGAIN;
2332 		break;
2333 	case -EINVAL:
2334 		/* Happens, for instance, if the user specified a link
2335 		 * local IPv6 address without a scope-id.
2336 		 */
2337 	case -ECONNREFUSED:
2338 	case -ECONNRESET:
2339 	case -ENETDOWN:
2340 	case -ENETUNREACH:
2341 	case -EHOSTUNREACH:
2342 	case -EADDRINUSE:
2343 	case -ENOBUFS:
2344 		break;
2345 	default:
2346 		printk("%s: connect returned unhandled error %d\n",
2347 			__func__, status);
2348 		status = -EAGAIN;
2349 	}
2350 
2351 	/* xs_tcp_force_close() wakes tasks with a fixed error code.
2352 	 * We need to wake them first to ensure the correct error code.
2353 	 */
2354 	xprt_wake_pending_tasks(xprt, status);
2355 	xs_tcp_force_close(xprt);
2356 out:
2357 	xprt_clear_connecting(xprt);
2358 out_unlock:
2359 	xprt_unlock_connect(xprt, transport);
2360 	current_restore_flags(pflags, PF_MEMALLOC);
2361 }
2362 
2363 /**
2364  * xs_connect - connect a socket to a remote endpoint
2365  * @xprt: pointer to transport structure
2366  * @task: address of RPC task that manages state of connect request
2367  *
2368  * TCP: If the remote end dropped the connection, delay reconnecting.
2369  *
2370  * UDP socket connects are synchronous, but we use a work queue anyway
2371  * to guarantee that even unprivileged user processes can set up a
2372  * socket on a privileged port.
2373  *
2374  * If a UDP socket connect fails, the delay behavior here prevents
2375  * retry floods (hard mounts).
2376  */
2377 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2378 {
2379 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2380 	unsigned long delay = 0;
2381 
2382 	WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));
2383 
2384 	if (transport->sock != NULL) {
2385 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2386 			"seconds\n", xprt, xprt->reestablish_timeout / HZ);
2387 
2388 		delay = xprt_reconnect_delay(xprt);
2389 		xprt_reconnect_backoff(xprt, XS_TCP_INIT_REEST_TO);
2390 
2391 	} else
2392 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2393 
2394 	queue_delayed_work(xprtiod_workqueue,
2395 			&transport->connect_worker,
2396 			delay);
2397 }
2398 
2399 static void xs_wake_disconnect(struct sock_xprt *transport)
2400 {
2401 	if (test_and_clear_bit(XPRT_SOCK_WAKE_DISCONNECT, &transport->sock_state))
2402 		xs_tcp_force_close(&transport->xprt);
2403 }
2404 
2405 static void xs_wake_write(struct sock_xprt *transport)
2406 {
2407 	if (test_and_clear_bit(XPRT_SOCK_WAKE_WRITE, &transport->sock_state))
2408 		xprt_write_space(&transport->xprt);
2409 }
2410 
2411 static void xs_wake_error(struct sock_xprt *transport)
2412 {
2413 	int sockerr;
2414 
2415 	if (!test_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state))
2416 		return;
2417 	mutex_lock(&transport->recv_mutex);
2418 	if (transport->sock == NULL)
2419 		goto out;
2420 	if (!test_and_clear_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state))
2421 		goto out;
2422 	sockerr = xchg(&transport->xprt_err, 0);
2423 	if (sockerr < 0)
2424 		xprt_wake_pending_tasks(&transport->xprt, sockerr);
2425 out:
2426 	mutex_unlock(&transport->recv_mutex);
2427 }
2428 
2429 static void xs_wake_pending(struct sock_xprt *transport)
2430 {
2431 	if (test_and_clear_bit(XPRT_SOCK_WAKE_PENDING, &transport->sock_state))
2432 		xprt_wake_pending_tasks(&transport->xprt, -EAGAIN);
2433 }
2434 
2435 static void xs_error_handle(struct work_struct *work)
2436 {
2437 	struct sock_xprt *transport = container_of(work,
2438 			struct sock_xprt, error_worker);
2439 
2440 	xs_wake_disconnect(transport);
2441 	xs_wake_write(transport);
2442 	xs_wake_error(transport);
2443 	xs_wake_pending(transport);
2444 }
2445 
2446 /**
2447  * xs_local_print_stats - display AF_LOCAL socket-specific stats
2448  * @xprt: rpc_xprt struct containing statistics
2449  * @seq: output file
2450  *
2451  */
2452 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2453 {
2454 	long idle_time = 0;
2455 
2456 	if (xprt_connected(xprt))
2457 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2458 
2459 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2460 			"%llu %llu %lu %llu %llu\n",
2461 			xprt->stat.bind_count,
2462 			xprt->stat.connect_count,
2463 			xprt->stat.connect_time / HZ,
2464 			idle_time,
2465 			xprt->stat.sends,
2466 			xprt->stat.recvs,
2467 			xprt->stat.bad_xids,
2468 			xprt->stat.req_u,
2469 			xprt->stat.bklog_u,
2470 			xprt->stat.max_slots,
2471 			xprt->stat.sending_u,
2472 			xprt->stat.pending_u);
2473 }
2474 
2475 /**
2476  * xs_udp_print_stats - display UDP socket-specific stats
2477  * @xprt: rpc_xprt struct containing statistics
2478  * @seq: output file
2479  *
2480  */
2481 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2482 {
2483 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2484 
2485 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2486 			"%lu %llu %llu\n",
2487 			transport->srcport,
2488 			xprt->stat.bind_count,
2489 			xprt->stat.sends,
2490 			xprt->stat.recvs,
2491 			xprt->stat.bad_xids,
2492 			xprt->stat.req_u,
2493 			xprt->stat.bklog_u,
2494 			xprt->stat.max_slots,
2495 			xprt->stat.sending_u,
2496 			xprt->stat.pending_u);
2497 }
2498 
2499 /**
2500  * xs_tcp_print_stats - display TCP socket-specific stats
2501  * @xprt: rpc_xprt struct containing statistics
2502  * @seq: output file
2503  *
2504  */
2505 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2506 {
2507 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2508 	long idle_time = 0;
2509 
2510 	if (xprt_connected(xprt))
2511 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2512 
2513 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2514 			"%llu %llu %lu %llu %llu\n",
2515 			transport->srcport,
2516 			xprt->stat.bind_count,
2517 			xprt->stat.connect_count,
2518 			xprt->stat.connect_time / HZ,
2519 			idle_time,
2520 			xprt->stat.sends,
2521 			xprt->stat.recvs,
2522 			xprt->stat.bad_xids,
2523 			xprt->stat.req_u,
2524 			xprt->stat.bklog_u,
2525 			xprt->stat.max_slots,
2526 			xprt->stat.sending_u,
2527 			xprt->stat.pending_u);
2528 }
2529 
2530 /*
2531  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2532  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2533  * to use the server side send routines.
2534  */
2535 static int bc_malloc(struct rpc_task *task)
2536 {
2537 	struct rpc_rqst *rqst = task->tk_rqstp;
2538 	size_t size = rqst->rq_callsize;
2539 	struct page *page;
2540 	struct rpc_buffer *buf;
2541 
2542 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer)) {
2543 		WARN_ONCE(1, "xprtsock: large bc buffer request (size %zu)\n",
2544 			  size);
2545 		return -EINVAL;
2546 	}
2547 
2548 	page = alloc_page(GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
2549 	if (!page)
2550 		return -ENOMEM;
2551 
2552 	buf = page_address(page);
2553 	buf->len = PAGE_SIZE;
2554 
2555 	rqst->rq_buffer = buf->data;
2556 	rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
2557 	return 0;
2558 }
2559 
2560 /*
2561  * Free the space allocated in the bc_alloc routine
2562  */
2563 static void bc_free(struct rpc_task *task)
2564 {
2565 	void *buffer = task->tk_rqstp->rq_buffer;
2566 	struct rpc_buffer *buf;
2567 
2568 	buf = container_of(buffer, struct rpc_buffer, data);
2569 	free_page((unsigned long)buf);
2570 }
2571 
2572 static int bc_sendto(struct rpc_rqst *req)
2573 {
2574 	struct xdr_buf *xdr = &req->rq_snd_buf;
2575 	struct sock_xprt *transport =
2576 			container_of(req->rq_xprt, struct sock_xprt, xprt);
2577 	struct msghdr msg = {
2578 		.msg_flags	= 0,
2579 	};
2580 	rpc_fraghdr marker = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT |
2581 					 (u32)xdr->len);
2582 	unsigned int sent = 0;
2583 	int err;
2584 
2585 	req->rq_xtime = ktime_get();
2586 	err = xdr_alloc_bvec(xdr, rpc_task_gfp_mask());
2587 	if (err < 0)
2588 		return err;
2589 	err = xprt_sock_sendmsg(transport->sock, &msg, xdr, 0, marker, &sent);
2590 	xdr_free_bvec(xdr);
2591 	if (err < 0 || sent != (xdr->len + sizeof(marker)))
2592 		return -EAGAIN;
2593 	return sent;
2594 }
2595 
2596 /**
2597  * bc_send_request - Send a backchannel Call on a TCP socket
2598  * @req: rpc_rqst containing Call message to be sent
2599  *
2600  * xpt_mutex ensures @rqstp's whole message is written to the socket
2601  * without interruption.
2602  *
2603  * Return values:
2604  *   %0 if the message was sent successfully
2605  *   %ENOTCONN if the message was not sent
2606  */
2607 static int bc_send_request(struct rpc_rqst *req)
2608 {
2609 	struct svc_xprt	*xprt;
2610 	int len;
2611 
2612 	/*
2613 	 * Get the server socket associated with this callback xprt
2614 	 */
2615 	xprt = req->rq_xprt->bc_xprt;
2616 
2617 	/*
2618 	 * Grab the mutex to serialize data as the connection is shared
2619 	 * with the fore channel
2620 	 */
2621 	mutex_lock(&xprt->xpt_mutex);
2622 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2623 		len = -ENOTCONN;
2624 	else
2625 		len = bc_sendto(req);
2626 	mutex_unlock(&xprt->xpt_mutex);
2627 
2628 	if (len > 0)
2629 		len = 0;
2630 
2631 	return len;
2632 }
2633 
2634 /*
2635  * The close routine. Since this is client initiated, we do nothing
2636  */
2637 
2638 static void bc_close(struct rpc_xprt *xprt)
2639 {
2640 	xprt_disconnect_done(xprt);
2641 }
2642 
2643 /*
2644  * The xprt destroy routine. Again, because this connection is client
2645  * initiated, we do nothing
2646  */
2647 
2648 static void bc_destroy(struct rpc_xprt *xprt)
2649 {
2650 	dprintk("RPC:       bc_destroy xprt %p\n", xprt);
2651 
2652 	xs_xprt_free(xprt);
2653 	module_put(THIS_MODULE);
2654 }
2655 
2656 static const struct rpc_xprt_ops xs_local_ops = {
2657 	.reserve_xprt		= xprt_reserve_xprt,
2658 	.release_xprt		= xprt_release_xprt,
2659 	.alloc_slot		= xprt_alloc_slot,
2660 	.free_slot		= xprt_free_slot,
2661 	.rpcbind		= xs_local_rpcbind,
2662 	.set_port		= xs_local_set_port,
2663 	.connect		= xs_local_connect,
2664 	.buf_alloc		= rpc_malloc,
2665 	.buf_free		= rpc_free,
2666 	.prepare_request	= xs_stream_prepare_request,
2667 	.send_request		= xs_local_send_request,
2668 	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
2669 	.close			= xs_close,
2670 	.destroy		= xs_destroy,
2671 	.print_stats		= xs_local_print_stats,
2672 	.enable_swap		= xs_enable_swap,
2673 	.disable_swap		= xs_disable_swap,
2674 };
2675 
2676 static const struct rpc_xprt_ops xs_udp_ops = {
2677 	.set_buffer_size	= xs_udp_set_buffer_size,
2678 	.reserve_xprt		= xprt_reserve_xprt_cong,
2679 	.release_xprt		= xprt_release_xprt_cong,
2680 	.alloc_slot		= xprt_alloc_slot,
2681 	.free_slot		= xprt_free_slot,
2682 	.rpcbind		= rpcb_getport_async,
2683 	.set_port		= xs_set_port,
2684 	.connect		= xs_connect,
2685 	.get_srcaddr		= xs_sock_srcaddr,
2686 	.get_srcport		= xs_sock_srcport,
2687 	.buf_alloc		= rpc_malloc,
2688 	.buf_free		= rpc_free,
2689 	.send_request		= xs_udp_send_request,
2690 	.wait_for_reply_request	= xprt_wait_for_reply_request_rtt,
2691 	.timer			= xs_udp_timer,
2692 	.release_request	= xprt_release_rqst_cong,
2693 	.close			= xs_close,
2694 	.destroy		= xs_destroy,
2695 	.print_stats		= xs_udp_print_stats,
2696 	.enable_swap		= xs_enable_swap,
2697 	.disable_swap		= xs_disable_swap,
2698 	.inject_disconnect	= xs_inject_disconnect,
2699 };
2700 
2701 static const struct rpc_xprt_ops xs_tcp_ops = {
2702 	.reserve_xprt		= xprt_reserve_xprt,
2703 	.release_xprt		= xprt_release_xprt,
2704 	.alloc_slot		= xprt_alloc_slot,
2705 	.free_slot		= xprt_free_slot,
2706 	.rpcbind		= rpcb_getport_async,
2707 	.set_port		= xs_set_port,
2708 	.connect		= xs_connect,
2709 	.get_srcaddr		= xs_sock_srcaddr,
2710 	.get_srcport		= xs_sock_srcport,
2711 	.buf_alloc		= rpc_malloc,
2712 	.buf_free		= rpc_free,
2713 	.prepare_request	= xs_stream_prepare_request,
2714 	.send_request		= xs_tcp_send_request,
2715 	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
2716 	.close			= xs_tcp_shutdown,
2717 	.destroy		= xs_destroy,
2718 	.set_connect_timeout	= xs_tcp_set_connect_timeout,
2719 	.print_stats		= xs_tcp_print_stats,
2720 	.enable_swap		= xs_enable_swap,
2721 	.disable_swap		= xs_disable_swap,
2722 	.inject_disconnect	= xs_inject_disconnect,
2723 #ifdef CONFIG_SUNRPC_BACKCHANNEL
2724 	.bc_setup		= xprt_setup_bc,
2725 	.bc_maxpayload		= xs_tcp_bc_maxpayload,
2726 	.bc_num_slots		= xprt_bc_max_slots,
2727 	.bc_free_rqst		= xprt_free_bc_rqst,
2728 	.bc_destroy		= xprt_destroy_bc,
2729 #endif
2730 };
2731 
2732 /*
2733  * The rpc_xprt_ops for the server backchannel
2734  */
2735 
2736 static const struct rpc_xprt_ops bc_tcp_ops = {
2737 	.reserve_xprt		= xprt_reserve_xprt,
2738 	.release_xprt		= xprt_release_xprt,
2739 	.alloc_slot		= xprt_alloc_slot,
2740 	.free_slot		= xprt_free_slot,
2741 	.buf_alloc		= bc_malloc,
2742 	.buf_free		= bc_free,
2743 	.send_request		= bc_send_request,
2744 	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
2745 	.close			= bc_close,
2746 	.destroy		= bc_destroy,
2747 	.print_stats		= xs_tcp_print_stats,
2748 	.enable_swap		= xs_enable_swap,
2749 	.disable_swap		= xs_disable_swap,
2750 	.inject_disconnect	= xs_inject_disconnect,
2751 };
2752 
2753 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2754 {
2755 	static const struct sockaddr_in sin = {
2756 		.sin_family		= AF_INET,
2757 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2758 	};
2759 	static const struct sockaddr_in6 sin6 = {
2760 		.sin6_family		= AF_INET6,
2761 		.sin6_addr		= IN6ADDR_ANY_INIT,
2762 	};
2763 
2764 	switch (family) {
2765 	case AF_LOCAL:
2766 		break;
2767 	case AF_INET:
2768 		memcpy(sap, &sin, sizeof(sin));
2769 		break;
2770 	case AF_INET6:
2771 		memcpy(sap, &sin6, sizeof(sin6));
2772 		break;
2773 	default:
2774 		dprintk("RPC:       %s: Bad address family\n", __func__);
2775 		return -EAFNOSUPPORT;
2776 	}
2777 	return 0;
2778 }
2779 
2780 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2781 				      unsigned int slot_table_size,
2782 				      unsigned int max_slot_table_size)
2783 {
2784 	struct rpc_xprt *xprt;
2785 	struct sock_xprt *new;
2786 
2787 	if (args->addrlen > sizeof(xprt->addr)) {
2788 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2789 		return ERR_PTR(-EBADF);
2790 	}
2791 
2792 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2793 			max_slot_table_size);
2794 	if (xprt == NULL) {
2795 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2796 				"rpc_xprt\n");
2797 		return ERR_PTR(-ENOMEM);
2798 	}
2799 
2800 	new = container_of(xprt, struct sock_xprt, xprt);
2801 	mutex_init(&new->recv_mutex);
2802 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2803 	xprt->addrlen = args->addrlen;
2804 	if (args->srcaddr)
2805 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2806 	else {
2807 		int err;
2808 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2809 					(struct sockaddr *)&new->srcaddr);
2810 		if (err != 0) {
2811 			xprt_free(xprt);
2812 			return ERR_PTR(err);
2813 		}
2814 	}
2815 
2816 	return xprt;
2817 }
2818 
2819 static const struct rpc_timeout xs_local_default_timeout = {
2820 	.to_initval = 10 * HZ,
2821 	.to_maxval = 10 * HZ,
2822 	.to_retries = 2,
2823 };
2824 
2825 /**
2826  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2827  * @args: rpc transport creation arguments
2828  *
2829  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2830  */
2831 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2832 {
2833 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2834 	struct sock_xprt *transport;
2835 	struct rpc_xprt *xprt;
2836 	struct rpc_xprt *ret;
2837 
2838 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2839 			xprt_max_tcp_slot_table_entries);
2840 	if (IS_ERR(xprt))
2841 		return xprt;
2842 	transport = container_of(xprt, struct sock_xprt, xprt);
2843 
2844 	xprt->prot = 0;
2845 	xprt->xprt_class = &xs_local_transport;
2846 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2847 
2848 	xprt->bind_timeout = XS_BIND_TO;
2849 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2850 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2851 
2852 	xprt->ops = &xs_local_ops;
2853 	xprt->timeout = &xs_local_default_timeout;
2854 
2855 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
2856 	INIT_WORK(&transport->error_worker, xs_error_handle);
2857 	INIT_DELAYED_WORK(&transport->connect_worker, xs_dummy_setup_socket);
2858 
2859 	switch (sun->sun_family) {
2860 	case AF_LOCAL:
2861 		if (sun->sun_path[0] != '/') {
2862 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2863 					sun->sun_path);
2864 			ret = ERR_PTR(-EINVAL);
2865 			goto out_err;
2866 		}
2867 		xprt_set_bound(xprt);
2868 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2869 		break;
2870 	default:
2871 		ret = ERR_PTR(-EAFNOSUPPORT);
2872 		goto out_err;
2873 	}
2874 
2875 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2876 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2877 
2878 	if (try_module_get(THIS_MODULE))
2879 		return xprt;
2880 	ret = ERR_PTR(-EINVAL);
2881 out_err:
2882 	xs_xprt_free(xprt);
2883 	return ret;
2884 }
2885 
2886 static const struct rpc_timeout xs_udp_default_timeout = {
2887 	.to_initval = 5 * HZ,
2888 	.to_maxval = 30 * HZ,
2889 	.to_increment = 5 * HZ,
2890 	.to_retries = 5,
2891 };
2892 
2893 /**
2894  * xs_setup_udp - Set up transport to use a UDP socket
2895  * @args: rpc transport creation arguments
2896  *
2897  */
2898 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2899 {
2900 	struct sockaddr *addr = args->dstaddr;
2901 	struct rpc_xprt *xprt;
2902 	struct sock_xprt *transport;
2903 	struct rpc_xprt *ret;
2904 
2905 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2906 			xprt_udp_slot_table_entries);
2907 	if (IS_ERR(xprt))
2908 		return xprt;
2909 	transport = container_of(xprt, struct sock_xprt, xprt);
2910 
2911 	xprt->prot = IPPROTO_UDP;
2912 	xprt->xprt_class = &xs_udp_transport;
2913 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2914 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2915 
2916 	xprt->bind_timeout = XS_BIND_TO;
2917 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2918 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2919 
2920 	xprt->ops = &xs_udp_ops;
2921 
2922 	xprt->timeout = &xs_udp_default_timeout;
2923 
2924 	INIT_WORK(&transport->recv_worker, xs_udp_data_receive_workfn);
2925 	INIT_WORK(&transport->error_worker, xs_error_handle);
2926 	INIT_DELAYED_WORK(&transport->connect_worker, xs_udp_setup_socket);
2927 
2928 	switch (addr->sa_family) {
2929 	case AF_INET:
2930 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2931 			xprt_set_bound(xprt);
2932 
2933 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2934 		break;
2935 	case AF_INET6:
2936 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2937 			xprt_set_bound(xprt);
2938 
2939 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2940 		break;
2941 	default:
2942 		ret = ERR_PTR(-EAFNOSUPPORT);
2943 		goto out_err;
2944 	}
2945 
2946 	if (xprt_bound(xprt))
2947 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2948 				xprt->address_strings[RPC_DISPLAY_ADDR],
2949 				xprt->address_strings[RPC_DISPLAY_PORT],
2950 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2951 	else
2952 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2953 				xprt->address_strings[RPC_DISPLAY_ADDR],
2954 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2955 
2956 	if (try_module_get(THIS_MODULE))
2957 		return xprt;
2958 	ret = ERR_PTR(-EINVAL);
2959 out_err:
2960 	xs_xprt_free(xprt);
2961 	return ret;
2962 }
2963 
2964 static const struct rpc_timeout xs_tcp_default_timeout = {
2965 	.to_initval = 60 * HZ,
2966 	.to_maxval = 60 * HZ,
2967 	.to_retries = 2,
2968 };
2969 
2970 /**
2971  * xs_setup_tcp - Set up transport to use a TCP socket
2972  * @args: rpc transport creation arguments
2973  *
2974  */
2975 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2976 {
2977 	struct sockaddr *addr = args->dstaddr;
2978 	struct rpc_xprt *xprt;
2979 	struct sock_xprt *transport;
2980 	struct rpc_xprt *ret;
2981 	unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
2982 
2983 	if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
2984 		max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;
2985 
2986 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2987 			max_slot_table_size);
2988 	if (IS_ERR(xprt))
2989 		return xprt;
2990 	transport = container_of(xprt, struct sock_xprt, xprt);
2991 
2992 	xprt->prot = IPPROTO_TCP;
2993 	xprt->xprt_class = &xs_tcp_transport;
2994 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2995 
2996 	xprt->bind_timeout = XS_BIND_TO;
2997 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2998 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2999 
3000 	xprt->ops = &xs_tcp_ops;
3001 	xprt->timeout = &xs_tcp_default_timeout;
3002 
3003 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
3004 	xprt->connect_timeout = xprt->timeout->to_initval *
3005 		(xprt->timeout->to_retries + 1);
3006 
3007 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
3008 	INIT_WORK(&transport->error_worker, xs_error_handle);
3009 	INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_setup_socket);
3010 
3011 	switch (addr->sa_family) {
3012 	case AF_INET:
3013 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
3014 			xprt_set_bound(xprt);
3015 
3016 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
3017 		break;
3018 	case AF_INET6:
3019 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
3020 			xprt_set_bound(xprt);
3021 
3022 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
3023 		break;
3024 	default:
3025 		ret = ERR_PTR(-EAFNOSUPPORT);
3026 		goto out_err;
3027 	}
3028 
3029 	if (xprt_bound(xprt))
3030 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3031 				xprt->address_strings[RPC_DISPLAY_ADDR],
3032 				xprt->address_strings[RPC_DISPLAY_PORT],
3033 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3034 	else
3035 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3036 				xprt->address_strings[RPC_DISPLAY_ADDR],
3037 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3038 
3039 	if (try_module_get(THIS_MODULE))
3040 		return xprt;
3041 	ret = ERR_PTR(-EINVAL);
3042 out_err:
3043 	xs_xprt_free(xprt);
3044 	return ret;
3045 }
3046 
3047 /**
3048  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
3049  * @args: rpc transport creation arguments
3050  *
3051  */
3052 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
3053 {
3054 	struct sockaddr *addr = args->dstaddr;
3055 	struct rpc_xprt *xprt;
3056 	struct sock_xprt *transport;
3057 	struct svc_sock *bc_sock;
3058 	struct rpc_xprt *ret;
3059 
3060 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3061 			xprt_tcp_slot_table_entries);
3062 	if (IS_ERR(xprt))
3063 		return xprt;
3064 	transport = container_of(xprt, struct sock_xprt, xprt);
3065 
3066 	xprt->prot = IPPROTO_TCP;
3067 	xprt->xprt_class = &xs_bc_tcp_transport;
3068 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3069 	xprt->timeout = &xs_tcp_default_timeout;
3070 
3071 	/* backchannel */
3072 	xprt_set_bound(xprt);
3073 	xprt->bind_timeout = 0;
3074 	xprt->reestablish_timeout = 0;
3075 	xprt->idle_timeout = 0;
3076 
3077 	xprt->ops = &bc_tcp_ops;
3078 
3079 	switch (addr->sa_family) {
3080 	case AF_INET:
3081 		xs_format_peer_addresses(xprt, "tcp",
3082 					 RPCBIND_NETID_TCP);
3083 		break;
3084 	case AF_INET6:
3085 		xs_format_peer_addresses(xprt, "tcp",
3086 				   RPCBIND_NETID_TCP6);
3087 		break;
3088 	default:
3089 		ret = ERR_PTR(-EAFNOSUPPORT);
3090 		goto out_err;
3091 	}
3092 
3093 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3094 			xprt->address_strings[RPC_DISPLAY_ADDR],
3095 			xprt->address_strings[RPC_DISPLAY_PORT],
3096 			xprt->address_strings[RPC_DISPLAY_PROTO]);
3097 
3098 	/*
3099 	 * Once we've associated a backchannel xprt with a connection,
3100 	 * we want to keep it around as long as the connection lasts,
3101 	 * in case we need to start using it for a backchannel again;
3102 	 * this reference won't be dropped until bc_xprt is destroyed.
3103 	 */
3104 	xprt_get(xprt);
3105 	args->bc_xprt->xpt_bc_xprt = xprt;
3106 	xprt->bc_xprt = args->bc_xprt;
3107 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
3108 	transport->sock = bc_sock->sk_sock;
3109 	transport->inet = bc_sock->sk_sk;
3110 
3111 	/*
3112 	 * Since we don't want connections for the backchannel, we set
3113 	 * the xprt status to connected
3114 	 */
3115 	xprt_set_connected(xprt);
3116 
3117 	if (try_module_get(THIS_MODULE))
3118 		return xprt;
3119 
3120 	args->bc_xprt->xpt_bc_xprt = NULL;
3121 	args->bc_xprt->xpt_bc_xps = NULL;
3122 	xprt_put(xprt);
3123 	ret = ERR_PTR(-EINVAL);
3124 out_err:
3125 	xs_xprt_free(xprt);
3126 	return ret;
3127 }
3128 
3129 static struct xprt_class	xs_local_transport = {
3130 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
3131 	.name		= "named UNIX socket",
3132 	.owner		= THIS_MODULE,
3133 	.ident		= XPRT_TRANSPORT_LOCAL,
3134 	.setup		= xs_setup_local,
3135 	.netid		= { "" },
3136 };
3137 
3138 static struct xprt_class	xs_udp_transport = {
3139 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
3140 	.name		= "udp",
3141 	.owner		= THIS_MODULE,
3142 	.ident		= XPRT_TRANSPORT_UDP,
3143 	.setup		= xs_setup_udp,
3144 	.netid		= { "udp", "udp6", "" },
3145 };
3146 
3147 static struct xprt_class	xs_tcp_transport = {
3148 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
3149 	.name		= "tcp",
3150 	.owner		= THIS_MODULE,
3151 	.ident		= XPRT_TRANSPORT_TCP,
3152 	.setup		= xs_setup_tcp,
3153 	.netid		= { "tcp", "tcp6", "" },
3154 };
3155 
3156 static struct xprt_class	xs_bc_tcp_transport = {
3157 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
3158 	.name		= "tcp NFSv4.1 backchannel",
3159 	.owner		= THIS_MODULE,
3160 	.ident		= XPRT_TRANSPORT_BC_TCP,
3161 	.setup		= xs_setup_bc_tcp,
3162 	.netid		= { "" },
3163 };
3164 
3165 /**
3166  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
3167  *
3168  */
3169 int init_socket_xprt(void)
3170 {
3171 	if (!sunrpc_table_header)
3172 		sunrpc_table_header = register_sysctl("sunrpc", xs_tunables_table);
3173 
3174 	xprt_register_transport(&xs_local_transport);
3175 	xprt_register_transport(&xs_udp_transport);
3176 	xprt_register_transport(&xs_tcp_transport);
3177 	xprt_register_transport(&xs_bc_tcp_transport);
3178 
3179 	return 0;
3180 }
3181 
3182 /**
3183  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
3184  *
3185  */
3186 void cleanup_socket_xprt(void)
3187 {
3188 	if (sunrpc_table_header) {
3189 		unregister_sysctl_table(sunrpc_table_header);
3190 		sunrpc_table_header = NULL;
3191 	}
3192 
3193 	xprt_unregister_transport(&xs_local_transport);
3194 	xprt_unregister_transport(&xs_udp_transport);
3195 	xprt_unregister_transport(&xs_tcp_transport);
3196 	xprt_unregister_transport(&xs_bc_tcp_transport);
3197 }
3198 
3199 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3200 {
3201 	return param_set_uint_minmax(val, kp,
3202 			RPC_MIN_RESVPORT,
3203 			RPC_MAX_RESVPORT);
3204 }
3205 
3206 static const struct kernel_param_ops param_ops_portnr = {
3207 	.set = param_set_portnr,
3208 	.get = param_get_uint,
3209 };
3210 
3211 #define param_check_portnr(name, p) \
3212 	__param_check(name, p, unsigned int);
3213 
3214 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3215 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3216 
3217 static int param_set_slot_table_size(const char *val,
3218 				     const struct kernel_param *kp)
3219 {
3220 	return param_set_uint_minmax(val, kp,
3221 			RPC_MIN_SLOT_TABLE,
3222 			RPC_MAX_SLOT_TABLE);
3223 }
3224 
3225 static const struct kernel_param_ops param_ops_slot_table_size = {
3226 	.set = param_set_slot_table_size,
3227 	.get = param_get_uint,
3228 };
3229 
3230 #define param_check_slot_table_size(name, p) \
3231 	__param_check(name, p, unsigned int);
3232 
3233 static int param_set_max_slot_table_size(const char *val,
3234 				     const struct kernel_param *kp)
3235 {
3236 	return param_set_uint_minmax(val, kp,
3237 			RPC_MIN_SLOT_TABLE,
3238 			RPC_MAX_SLOT_TABLE_LIMIT);
3239 }
3240 
3241 static const struct kernel_param_ops param_ops_max_slot_table_size = {
3242 	.set = param_set_max_slot_table_size,
3243 	.get = param_get_uint,
3244 };
3245 
3246 #define param_check_max_slot_table_size(name, p) \
3247 	__param_check(name, p, unsigned int);
3248 
3249 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3250 		   slot_table_size, 0644);
3251 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3252 		   max_slot_table_size, 0644);
3253 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3254 		   slot_table_size, 0644);
3255