xref: /linux/net/sunrpc/xprtsock.c (revision c145211d1f9e2ef19e7b4c2b943f68366daa97af)
1 /*
2  * linux/net/sunrpc/xprtsock.c
3  *
4  * Client-side transport implementation for sockets.
5  *
6  * TCP callback races fixes (C) 1998 Red Hat
7  * TCP send fixes (C) 1998 Red Hat
8  * TCP NFS related read + write fixes
9  *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
10  *
11  * Rewrite of larges part of the code in order to stabilize TCP stuff.
12  * Fix behaviour when socket buffer is full.
13  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
14  *
15  * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
16  *
17  * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
18  *   <gilles.quillard@bull.net>
19  */
20 
21 #include <linux/types.h>
22 #include <linux/slab.h>
23 #include <linux/module.h>
24 #include <linux/capability.h>
25 #include <linux/pagemap.h>
26 #include <linux/errno.h>
27 #include <linux/socket.h>
28 #include <linux/in.h>
29 #include <linux/net.h>
30 #include <linux/mm.h>
31 #include <linux/udp.h>
32 #include <linux/tcp.h>
33 #include <linux/sunrpc/clnt.h>
34 #include <linux/sunrpc/sched.h>
35 #include <linux/sunrpc/svcsock.h>
36 #include <linux/sunrpc/xprtsock.h>
37 #include <linux/file.h>
38 #ifdef CONFIG_NFS_V4_1
39 #include <linux/sunrpc/bc_xprt.h>
40 #endif
41 
42 #include <net/sock.h>
43 #include <net/checksum.h>
44 #include <net/udp.h>
45 #include <net/tcp.h>
46 
47 #include "sunrpc.h"
48 /*
49  * xprtsock tunables
50  */
51 unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
52 unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE;
53 
54 unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
55 unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
56 
57 #define XS_TCP_LINGER_TO	(15U * HZ)
58 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
59 
60 /*
61  * We can register our own files under /proc/sys/sunrpc by
62  * calling register_sysctl_table() again.  The files in that
63  * directory become the union of all files registered there.
64  *
65  * We simply need to make sure that we don't collide with
66  * someone else's file names!
67  */
68 
69 #ifdef RPC_DEBUG
70 
71 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
72 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
73 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
74 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
75 
76 static struct ctl_table_header *sunrpc_table_header;
77 
78 /*
79  * FIXME: changing the UDP slot table size should also resize the UDP
80  *        socket buffers for existing UDP transports
81  */
82 static ctl_table xs_tunables_table[] = {
83 	{
84 		.procname	= "udp_slot_table_entries",
85 		.data		= &xprt_udp_slot_table_entries,
86 		.maxlen		= sizeof(unsigned int),
87 		.mode		= 0644,
88 		.proc_handler	= proc_dointvec_minmax,
89 		.extra1		= &min_slot_table_size,
90 		.extra2		= &max_slot_table_size
91 	},
92 	{
93 		.procname	= "tcp_slot_table_entries",
94 		.data		= &xprt_tcp_slot_table_entries,
95 		.maxlen		= sizeof(unsigned int),
96 		.mode		= 0644,
97 		.proc_handler	= proc_dointvec_minmax,
98 		.extra1		= &min_slot_table_size,
99 		.extra2		= &max_slot_table_size
100 	},
101 	{
102 		.procname	= "min_resvport",
103 		.data		= &xprt_min_resvport,
104 		.maxlen		= sizeof(unsigned int),
105 		.mode		= 0644,
106 		.proc_handler	= proc_dointvec_minmax,
107 		.extra1		= &xprt_min_resvport_limit,
108 		.extra2		= &xprt_max_resvport_limit
109 	},
110 	{
111 		.procname	= "max_resvport",
112 		.data		= &xprt_max_resvport,
113 		.maxlen		= sizeof(unsigned int),
114 		.mode		= 0644,
115 		.proc_handler	= proc_dointvec_minmax,
116 		.extra1		= &xprt_min_resvport_limit,
117 		.extra2		= &xprt_max_resvport_limit
118 	},
119 	{
120 		.procname	= "tcp_fin_timeout",
121 		.data		= &xs_tcp_fin_timeout,
122 		.maxlen		= sizeof(xs_tcp_fin_timeout),
123 		.mode		= 0644,
124 		.proc_handler	= proc_dointvec_jiffies,
125 	},
126 	{ },
127 };
128 
129 static ctl_table sunrpc_table[] = {
130 	{
131 		.procname	= "sunrpc",
132 		.mode		= 0555,
133 		.child		= xs_tunables_table
134 	},
135 	{ },
136 };
137 
138 #endif
139 
140 /*
141  * Wait duration for a reply from the RPC portmapper.
142  */
143 #define XS_BIND_TO		(60U * HZ)
144 
145 /*
146  * Delay if a UDP socket connect error occurs.  This is most likely some
147  * kind of resource problem on the local host.
148  */
149 #define XS_UDP_REEST_TO		(2U * HZ)
150 
151 /*
152  * The reestablish timeout allows clients to delay for a bit before attempting
153  * to reconnect to a server that just dropped our connection.
154  *
155  * We implement an exponential backoff when trying to reestablish a TCP
156  * transport connection with the server.  Some servers like to drop a TCP
157  * connection when they are overworked, so we start with a short timeout and
158  * increase over time if the server is down or not responding.
159  */
160 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
161 #define XS_TCP_MAX_REEST_TO	(5U * 60 * HZ)
162 
163 /*
164  * TCP idle timeout; client drops the transport socket if it is idle
165  * for this long.  Note that we also timeout UDP sockets to prevent
166  * holding port numbers when there is no RPC traffic.
167  */
168 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
169 
170 #ifdef RPC_DEBUG
171 # undef  RPC_DEBUG_DATA
172 # define RPCDBG_FACILITY	RPCDBG_TRANS
173 #endif
174 
175 #ifdef RPC_DEBUG_DATA
176 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
177 {
178 	u8 *buf = (u8 *) packet;
179 	int j;
180 
181 	dprintk("RPC:       %s\n", msg);
182 	for (j = 0; j < count && j < 128; j += 4) {
183 		if (!(j & 31)) {
184 			if (j)
185 				dprintk("\n");
186 			dprintk("0x%04x ", j);
187 		}
188 		dprintk("%02x%02x%02x%02x ",
189 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
190 	}
191 	dprintk("\n");
192 }
193 #else
194 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
195 {
196 	/* NOP */
197 }
198 #endif
199 
200 struct sock_xprt {
201 	struct rpc_xprt		xprt;
202 
203 	/*
204 	 * Network layer
205 	 */
206 	struct socket *		sock;
207 	struct sock *		inet;
208 
209 	/*
210 	 * State of TCP reply receive
211 	 */
212 	__be32			tcp_fraghdr,
213 				tcp_xid;
214 
215 	u32			tcp_offset,
216 				tcp_reclen;
217 
218 	unsigned long		tcp_copied,
219 				tcp_flags;
220 
221 	/*
222 	 * Connection of transports
223 	 */
224 	struct delayed_work	connect_worker;
225 	struct sockaddr_storage	srcaddr;
226 	unsigned short		srcport;
227 
228 	/*
229 	 * UDP socket buffer size parameters
230 	 */
231 	size_t			rcvsize,
232 				sndsize;
233 
234 	/*
235 	 * Saved socket callback addresses
236 	 */
237 	void			(*old_data_ready)(struct sock *, int);
238 	void			(*old_state_change)(struct sock *);
239 	void			(*old_write_space)(struct sock *);
240 	void			(*old_error_report)(struct sock *);
241 };
242 
243 /*
244  * TCP receive state flags
245  */
246 #define TCP_RCV_LAST_FRAG	(1UL << 0)
247 #define TCP_RCV_COPY_FRAGHDR	(1UL << 1)
248 #define TCP_RCV_COPY_XID	(1UL << 2)
249 #define TCP_RCV_COPY_DATA	(1UL << 3)
250 #define TCP_RCV_READ_CALLDIR	(1UL << 4)
251 #define TCP_RCV_COPY_CALLDIR	(1UL << 5)
252 
253 /*
254  * TCP RPC flags
255  */
256 #define TCP_RPC_REPLY		(1UL << 6)
257 
258 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
259 {
260 	return (struct sockaddr *) &xprt->addr;
261 }
262 
263 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
264 {
265 	return (struct sockaddr_in *) &xprt->addr;
266 }
267 
268 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
269 {
270 	return (struct sockaddr_in6 *) &xprt->addr;
271 }
272 
273 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
274 {
275 	struct sockaddr *sap = xs_addr(xprt);
276 	struct sockaddr_in6 *sin6;
277 	struct sockaddr_in *sin;
278 	char buf[128];
279 
280 	(void)rpc_ntop(sap, buf, sizeof(buf));
281 	xprt->address_strings[RPC_DISPLAY_ADDR] = kstrdup(buf, GFP_KERNEL);
282 
283 	switch (sap->sa_family) {
284 	case AF_INET:
285 		sin = xs_addr_in(xprt);
286 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
287 		break;
288 	case AF_INET6:
289 		sin6 = xs_addr_in6(xprt);
290 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
291 		break;
292 	default:
293 		BUG();
294 	}
295 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
296 }
297 
298 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
299 {
300 	struct sockaddr *sap = xs_addr(xprt);
301 	char buf[128];
302 
303 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
304 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
305 
306 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
307 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
308 }
309 
310 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
311 				     const char *protocol,
312 				     const char *netid)
313 {
314 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
315 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
316 	xs_format_common_peer_addresses(xprt);
317 	xs_format_common_peer_ports(xprt);
318 }
319 
320 static void xs_update_peer_port(struct rpc_xprt *xprt)
321 {
322 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
323 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
324 
325 	xs_format_common_peer_ports(xprt);
326 }
327 
328 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
329 {
330 	unsigned int i;
331 
332 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
333 		switch (i) {
334 		case RPC_DISPLAY_PROTO:
335 		case RPC_DISPLAY_NETID:
336 			continue;
337 		default:
338 			kfree(xprt->address_strings[i]);
339 		}
340 }
341 
342 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
343 
344 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
345 {
346 	struct msghdr msg = {
347 		.msg_name	= addr,
348 		.msg_namelen	= addrlen,
349 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
350 	};
351 	struct kvec iov = {
352 		.iov_base	= vec->iov_base + base,
353 		.iov_len	= vec->iov_len - base,
354 	};
355 
356 	if (iov.iov_len != 0)
357 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
358 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
359 }
360 
361 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more)
362 {
363 	struct page **ppage;
364 	unsigned int remainder;
365 	int err, sent = 0;
366 
367 	remainder = xdr->page_len - base;
368 	base += xdr->page_base;
369 	ppage = xdr->pages + (base >> PAGE_SHIFT);
370 	base &= ~PAGE_MASK;
371 	for(;;) {
372 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
373 		int flags = XS_SENDMSG_FLAGS;
374 
375 		remainder -= len;
376 		if (remainder != 0 || more)
377 			flags |= MSG_MORE;
378 		err = sock->ops->sendpage(sock, *ppage, base, len, flags);
379 		if (remainder == 0 || err != len)
380 			break;
381 		sent += err;
382 		ppage++;
383 		base = 0;
384 	}
385 	if (sent == 0)
386 		return err;
387 	if (err > 0)
388 		sent += err;
389 	return sent;
390 }
391 
392 /**
393  * xs_sendpages - write pages directly to a socket
394  * @sock: socket to send on
395  * @addr: UDP only -- address of destination
396  * @addrlen: UDP only -- length of destination address
397  * @xdr: buffer containing this request
398  * @base: starting position in the buffer
399  *
400  */
401 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
402 {
403 	unsigned int remainder = xdr->len - base;
404 	int err, sent = 0;
405 
406 	if (unlikely(!sock))
407 		return -ENOTSOCK;
408 
409 	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
410 	if (base != 0) {
411 		addr = NULL;
412 		addrlen = 0;
413 	}
414 
415 	if (base < xdr->head[0].iov_len || addr != NULL) {
416 		unsigned int len = xdr->head[0].iov_len - base;
417 		remainder -= len;
418 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
419 		if (remainder == 0 || err != len)
420 			goto out;
421 		sent += err;
422 		base = 0;
423 	} else
424 		base -= xdr->head[0].iov_len;
425 
426 	if (base < xdr->page_len) {
427 		unsigned int len = xdr->page_len - base;
428 		remainder -= len;
429 		err = xs_send_pagedata(sock, xdr, base, remainder != 0);
430 		if (remainder == 0 || err != len)
431 			goto out;
432 		sent += err;
433 		base = 0;
434 	} else
435 		base -= xdr->page_len;
436 
437 	if (base >= xdr->tail[0].iov_len)
438 		return sent;
439 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
440 out:
441 	if (sent == 0)
442 		return err;
443 	if (err > 0)
444 		sent += err;
445 	return sent;
446 }
447 
448 static void xs_nospace_callback(struct rpc_task *task)
449 {
450 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
451 
452 	transport->inet->sk_write_pending--;
453 	clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
454 }
455 
456 /**
457  * xs_nospace - place task on wait queue if transmit was incomplete
458  * @task: task to put to sleep
459  *
460  */
461 static int xs_nospace(struct rpc_task *task)
462 {
463 	struct rpc_rqst *req = task->tk_rqstp;
464 	struct rpc_xprt *xprt = req->rq_xprt;
465 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
466 	int ret = 0;
467 
468 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
469 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
470 			req->rq_slen);
471 
472 	/* Protect against races with write_space */
473 	spin_lock_bh(&xprt->transport_lock);
474 
475 	/* Don't race with disconnect */
476 	if (xprt_connected(xprt)) {
477 		if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
478 			ret = -EAGAIN;
479 			/*
480 			 * Notify TCP that we're limited by the application
481 			 * window size
482 			 */
483 			set_bit(SOCK_NOSPACE, &transport->sock->flags);
484 			transport->inet->sk_write_pending++;
485 			/* ...and wait for more buffer space */
486 			xprt_wait_for_buffer_space(task, xs_nospace_callback);
487 		}
488 	} else {
489 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
490 		ret = -ENOTCONN;
491 	}
492 
493 	spin_unlock_bh(&xprt->transport_lock);
494 	return ret;
495 }
496 
497 /**
498  * xs_udp_send_request - write an RPC request to a UDP socket
499  * @task: address of RPC task that manages the state of an RPC request
500  *
501  * Return values:
502  *        0:	The request has been sent
503  *   EAGAIN:	The socket was blocked, please call again later to
504  *		complete the request
505  * ENOTCONN:	Caller needs to invoke connect logic then call again
506  *    other:	Some other error occured, the request was not sent
507  */
508 static int xs_udp_send_request(struct rpc_task *task)
509 {
510 	struct rpc_rqst *req = task->tk_rqstp;
511 	struct rpc_xprt *xprt = req->rq_xprt;
512 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
513 	struct xdr_buf *xdr = &req->rq_snd_buf;
514 	int status;
515 
516 	xs_pktdump("packet data:",
517 				req->rq_svec->iov_base,
518 				req->rq_svec->iov_len);
519 
520 	if (!xprt_bound(xprt))
521 		return -ENOTCONN;
522 	status = xs_sendpages(transport->sock,
523 			      xs_addr(xprt),
524 			      xprt->addrlen, xdr,
525 			      req->rq_bytes_sent);
526 
527 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
528 			xdr->len - req->rq_bytes_sent, status);
529 
530 	if (status >= 0) {
531 		req->rq_xmit_bytes_sent += status;
532 		if (status >= req->rq_slen)
533 			return 0;
534 		/* Still some bytes left; set up for a retry later. */
535 		status = -EAGAIN;
536 	}
537 
538 	switch (status) {
539 	case -ENOTSOCK:
540 		status = -ENOTCONN;
541 		/* Should we call xs_close() here? */
542 		break;
543 	case -EAGAIN:
544 		status = xs_nospace(task);
545 		break;
546 	default:
547 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
548 			-status);
549 	case -ENETUNREACH:
550 	case -EPIPE:
551 	case -ECONNREFUSED:
552 		/* When the server has died, an ICMP port unreachable message
553 		 * prompts ECONNREFUSED. */
554 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
555 	}
556 
557 	return status;
558 }
559 
560 /**
561  * xs_tcp_shutdown - gracefully shut down a TCP socket
562  * @xprt: transport
563  *
564  * Initiates a graceful shutdown of the TCP socket by calling the
565  * equivalent of shutdown(SHUT_WR);
566  */
567 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
568 {
569 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
570 	struct socket *sock = transport->sock;
571 
572 	if (sock != NULL)
573 		kernel_sock_shutdown(sock, SHUT_WR);
574 }
575 
576 static inline void xs_encode_tcp_record_marker(struct xdr_buf *buf)
577 {
578 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
579 	rpc_fraghdr *base = buf->head[0].iov_base;
580 	*base = htonl(RPC_LAST_STREAM_FRAGMENT | reclen);
581 }
582 
583 /**
584  * xs_tcp_send_request - write an RPC request to a TCP socket
585  * @task: address of RPC task that manages the state of an RPC request
586  *
587  * Return values:
588  *        0:	The request has been sent
589  *   EAGAIN:	The socket was blocked, please call again later to
590  *		complete the request
591  * ENOTCONN:	Caller needs to invoke connect logic then call again
592  *    other:	Some other error occured, the request was not sent
593  *
594  * XXX: In the case of soft timeouts, should we eventually give up
595  *	if sendmsg is not able to make progress?
596  */
597 static int xs_tcp_send_request(struct rpc_task *task)
598 {
599 	struct rpc_rqst *req = task->tk_rqstp;
600 	struct rpc_xprt *xprt = req->rq_xprt;
601 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
602 	struct xdr_buf *xdr = &req->rq_snd_buf;
603 	int status;
604 
605 	xs_encode_tcp_record_marker(&req->rq_snd_buf);
606 
607 	xs_pktdump("packet data:",
608 				req->rq_svec->iov_base,
609 				req->rq_svec->iov_len);
610 
611 	/* Continue transmitting the packet/record. We must be careful
612 	 * to cope with writespace callbacks arriving _after_ we have
613 	 * called sendmsg(). */
614 	while (1) {
615 		status = xs_sendpages(transport->sock,
616 					NULL, 0, xdr, req->rq_bytes_sent);
617 
618 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
619 				xdr->len - req->rq_bytes_sent, status);
620 
621 		if (unlikely(status < 0))
622 			break;
623 
624 		/* If we've sent the entire packet, immediately
625 		 * reset the count of bytes sent. */
626 		req->rq_bytes_sent += status;
627 		req->rq_xmit_bytes_sent += status;
628 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
629 			req->rq_bytes_sent = 0;
630 			return 0;
631 		}
632 
633 		if (status != 0)
634 			continue;
635 		status = -EAGAIN;
636 		break;
637 	}
638 
639 	switch (status) {
640 	case -ENOTSOCK:
641 		status = -ENOTCONN;
642 		/* Should we call xs_close() here? */
643 		break;
644 	case -EAGAIN:
645 		status = xs_nospace(task);
646 		break;
647 	default:
648 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
649 			-status);
650 	case -ECONNRESET:
651 	case -EPIPE:
652 		xs_tcp_shutdown(xprt);
653 	case -ECONNREFUSED:
654 	case -ENOTCONN:
655 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
656 	}
657 
658 	return status;
659 }
660 
661 /**
662  * xs_tcp_release_xprt - clean up after a tcp transmission
663  * @xprt: transport
664  * @task: rpc task
665  *
666  * This cleans up if an error causes us to abort the transmission of a request.
667  * In this case, the socket may need to be reset in order to avoid confusing
668  * the server.
669  */
670 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
671 {
672 	struct rpc_rqst *req;
673 
674 	if (task != xprt->snd_task)
675 		return;
676 	if (task == NULL)
677 		goto out_release;
678 	req = task->tk_rqstp;
679 	if (req->rq_bytes_sent == 0)
680 		goto out_release;
681 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
682 		goto out_release;
683 	set_bit(XPRT_CLOSE_WAIT, &task->tk_xprt->state);
684 out_release:
685 	xprt_release_xprt(xprt, task);
686 }
687 
688 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
689 {
690 	transport->old_data_ready = sk->sk_data_ready;
691 	transport->old_state_change = sk->sk_state_change;
692 	transport->old_write_space = sk->sk_write_space;
693 	transport->old_error_report = sk->sk_error_report;
694 }
695 
696 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
697 {
698 	sk->sk_data_ready = transport->old_data_ready;
699 	sk->sk_state_change = transport->old_state_change;
700 	sk->sk_write_space = transport->old_write_space;
701 	sk->sk_error_report = transport->old_error_report;
702 }
703 
704 static void xs_reset_transport(struct sock_xprt *transport)
705 {
706 	struct socket *sock = transport->sock;
707 	struct sock *sk = transport->inet;
708 
709 	if (sk == NULL)
710 		return;
711 
712 	write_lock_bh(&sk->sk_callback_lock);
713 	transport->inet = NULL;
714 	transport->sock = NULL;
715 
716 	sk->sk_user_data = NULL;
717 
718 	xs_restore_old_callbacks(transport, sk);
719 	write_unlock_bh(&sk->sk_callback_lock);
720 
721 	sk->sk_no_check = 0;
722 
723 	sock_release(sock);
724 }
725 
726 /**
727  * xs_close - close a socket
728  * @xprt: transport
729  *
730  * This is used when all requests are complete; ie, no DRC state remains
731  * on the server we want to save.
732  *
733  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
734  * xs_reset_transport() zeroing the socket from underneath a writer.
735  */
736 static void xs_close(struct rpc_xprt *xprt)
737 {
738 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
739 
740 	dprintk("RPC:       xs_close xprt %p\n", xprt);
741 
742 	xs_reset_transport(transport);
743 	xprt->reestablish_timeout = 0;
744 
745 	smp_mb__before_clear_bit();
746 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
747 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
748 	clear_bit(XPRT_CLOSING, &xprt->state);
749 	smp_mb__after_clear_bit();
750 	xprt_disconnect_done(xprt);
751 }
752 
753 static void xs_tcp_close(struct rpc_xprt *xprt)
754 {
755 	if (test_and_clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state))
756 		xs_close(xprt);
757 	else
758 		xs_tcp_shutdown(xprt);
759 }
760 
761 /**
762  * xs_destroy - prepare to shutdown a transport
763  * @xprt: doomed transport
764  *
765  */
766 static void xs_destroy(struct rpc_xprt *xprt)
767 {
768 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
769 
770 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
771 
772 	cancel_rearming_delayed_work(&transport->connect_worker);
773 
774 	xs_close(xprt);
775 	xs_free_peer_addresses(xprt);
776 	kfree(xprt->slot);
777 	kfree(xprt);
778 	module_put(THIS_MODULE);
779 }
780 
781 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
782 {
783 	return (struct rpc_xprt *) sk->sk_user_data;
784 }
785 
786 /**
787  * xs_udp_data_ready - "data ready" callback for UDP sockets
788  * @sk: socket with data to read
789  * @len: how much data to read
790  *
791  */
792 static void xs_udp_data_ready(struct sock *sk, int len)
793 {
794 	struct rpc_task *task;
795 	struct rpc_xprt *xprt;
796 	struct rpc_rqst *rovr;
797 	struct sk_buff *skb;
798 	int err, repsize, copied;
799 	u32 _xid;
800 	__be32 *xp;
801 
802 	read_lock(&sk->sk_callback_lock);
803 	dprintk("RPC:       xs_udp_data_ready...\n");
804 	if (!(xprt = xprt_from_sock(sk)))
805 		goto out;
806 
807 	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
808 		goto out;
809 
810 	if (xprt->shutdown)
811 		goto dropit;
812 
813 	repsize = skb->len - sizeof(struct udphdr);
814 	if (repsize < 4) {
815 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
816 		goto dropit;
817 	}
818 
819 	/* Copy the XID from the skb... */
820 	xp = skb_header_pointer(skb, sizeof(struct udphdr),
821 				sizeof(_xid), &_xid);
822 	if (xp == NULL)
823 		goto dropit;
824 
825 	/* Look up and lock the request corresponding to the given XID */
826 	spin_lock(&xprt->transport_lock);
827 	rovr = xprt_lookup_rqst(xprt, *xp);
828 	if (!rovr)
829 		goto out_unlock;
830 	task = rovr->rq_task;
831 
832 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
833 		copied = repsize;
834 
835 	/* Suck it into the iovec, verify checksum if not done by hw. */
836 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
837 		UDPX_INC_STATS_BH(sk, UDP_MIB_INERRORS);
838 		goto out_unlock;
839 	}
840 
841 	UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
842 
843 	/* Something worked... */
844 	dst_confirm(skb_dst(skb));
845 
846 	xprt_adjust_cwnd(task, copied);
847 	xprt_complete_rqst(task, copied);
848 
849  out_unlock:
850 	spin_unlock(&xprt->transport_lock);
851  dropit:
852 	skb_free_datagram(sk, skb);
853  out:
854 	read_unlock(&sk->sk_callback_lock);
855 }
856 
857 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
858 {
859 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
860 	size_t len, used;
861 	char *p;
862 
863 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
864 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
865 	used = xdr_skb_read_bits(desc, p, len);
866 	transport->tcp_offset += used;
867 	if (used != len)
868 		return;
869 
870 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
871 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
872 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
873 	else
874 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
875 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
876 
877 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
878 	transport->tcp_offset = 0;
879 
880 	/* Sanity check of the record length */
881 	if (unlikely(transport->tcp_reclen < 8)) {
882 		dprintk("RPC:       invalid TCP record fragment length\n");
883 		xprt_force_disconnect(xprt);
884 		return;
885 	}
886 	dprintk("RPC:       reading TCP record fragment of length %d\n",
887 			transport->tcp_reclen);
888 }
889 
890 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
891 {
892 	if (transport->tcp_offset == transport->tcp_reclen) {
893 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
894 		transport->tcp_offset = 0;
895 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
896 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
897 			transport->tcp_flags |= TCP_RCV_COPY_XID;
898 			transport->tcp_copied = 0;
899 		}
900 	}
901 }
902 
903 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
904 {
905 	size_t len, used;
906 	char *p;
907 
908 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
909 	dprintk("RPC:       reading XID (%Zu bytes)\n", len);
910 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
911 	used = xdr_skb_read_bits(desc, p, len);
912 	transport->tcp_offset += used;
913 	if (used != len)
914 		return;
915 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
916 	transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
917 	transport->tcp_copied = 4;
918 	dprintk("RPC:       reading %s XID %08x\n",
919 			(transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
920 							      : "request with",
921 			ntohl(transport->tcp_xid));
922 	xs_tcp_check_fraghdr(transport);
923 }
924 
925 static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
926 				       struct xdr_skb_reader *desc)
927 {
928 	size_t len, used;
929 	u32 offset;
930 	__be32	calldir;
931 
932 	/*
933 	 * We want transport->tcp_offset to be 8 at the end of this routine
934 	 * (4 bytes for the xid and 4 bytes for the call/reply flag).
935 	 * When this function is called for the first time,
936 	 * transport->tcp_offset is 4 (after having already read the xid).
937 	 */
938 	offset = transport->tcp_offset - sizeof(transport->tcp_xid);
939 	len = sizeof(calldir) - offset;
940 	dprintk("RPC:       reading CALL/REPLY flag (%Zu bytes)\n", len);
941 	used = xdr_skb_read_bits(desc, &calldir, len);
942 	transport->tcp_offset += used;
943 	if (used != len)
944 		return;
945 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
946 	transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
947 	transport->tcp_flags |= TCP_RCV_COPY_DATA;
948 	/*
949 	 * We don't yet have the XDR buffer, so we will write the calldir
950 	 * out after we get the buffer from the 'struct rpc_rqst'
951 	 */
952 	if (ntohl(calldir) == RPC_REPLY)
953 		transport->tcp_flags |= TCP_RPC_REPLY;
954 	else
955 		transport->tcp_flags &= ~TCP_RPC_REPLY;
956 	dprintk("RPC:       reading %s CALL/REPLY flag %08x\n",
957 			(transport->tcp_flags & TCP_RPC_REPLY) ?
958 				"reply for" : "request with", calldir);
959 	xs_tcp_check_fraghdr(transport);
960 }
961 
962 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
963 				     struct xdr_skb_reader *desc,
964 				     struct rpc_rqst *req)
965 {
966 	struct sock_xprt *transport =
967 				container_of(xprt, struct sock_xprt, xprt);
968 	struct xdr_buf *rcvbuf;
969 	size_t len;
970 	ssize_t r;
971 
972 	rcvbuf = &req->rq_private_buf;
973 
974 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
975 		/*
976 		 * Save the RPC direction in the XDR buffer
977 		 */
978 		__be32	calldir = transport->tcp_flags & TCP_RPC_REPLY ?
979 					htonl(RPC_REPLY) : 0;
980 
981 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
982 			&calldir, sizeof(calldir));
983 		transport->tcp_copied += sizeof(calldir);
984 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
985 	}
986 
987 	len = desc->count;
988 	if (len > transport->tcp_reclen - transport->tcp_offset) {
989 		struct xdr_skb_reader my_desc;
990 
991 		len = transport->tcp_reclen - transport->tcp_offset;
992 		memcpy(&my_desc, desc, sizeof(my_desc));
993 		my_desc.count = len;
994 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
995 					  &my_desc, xdr_skb_read_bits);
996 		desc->count -= r;
997 		desc->offset += r;
998 	} else
999 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1000 					  desc, xdr_skb_read_bits);
1001 
1002 	if (r > 0) {
1003 		transport->tcp_copied += r;
1004 		transport->tcp_offset += r;
1005 	}
1006 	if (r != len) {
1007 		/* Error when copying to the receive buffer,
1008 		 * usually because we weren't able to allocate
1009 		 * additional buffer pages. All we can do now
1010 		 * is turn off TCP_RCV_COPY_DATA, so the request
1011 		 * will not receive any additional updates,
1012 		 * and time out.
1013 		 * Any remaining data from this record will
1014 		 * be discarded.
1015 		 */
1016 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1017 		dprintk("RPC:       XID %08x truncated request\n",
1018 				ntohl(transport->tcp_xid));
1019 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1020 				"tcp_offset = %u, tcp_reclen = %u\n",
1021 				xprt, transport->tcp_copied,
1022 				transport->tcp_offset, transport->tcp_reclen);
1023 		return;
1024 	}
1025 
1026 	dprintk("RPC:       XID %08x read %Zd bytes\n",
1027 			ntohl(transport->tcp_xid), r);
1028 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1029 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1030 			transport->tcp_offset, transport->tcp_reclen);
1031 
1032 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1033 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1034 	else if (transport->tcp_offset == transport->tcp_reclen) {
1035 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1036 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1037 	}
1038 
1039 	return;
1040 }
1041 
1042 /*
1043  * Finds the request corresponding to the RPC xid and invokes the common
1044  * tcp read code to read the data.
1045  */
1046 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1047 				    struct xdr_skb_reader *desc)
1048 {
1049 	struct sock_xprt *transport =
1050 				container_of(xprt, struct sock_xprt, xprt);
1051 	struct rpc_rqst *req;
1052 
1053 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1054 
1055 	/* Find and lock the request corresponding to this xid */
1056 	spin_lock(&xprt->transport_lock);
1057 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1058 	if (!req) {
1059 		dprintk("RPC:       XID %08x request not found!\n",
1060 				ntohl(transport->tcp_xid));
1061 		spin_unlock(&xprt->transport_lock);
1062 		return -1;
1063 	}
1064 
1065 	xs_tcp_read_common(xprt, desc, req);
1066 
1067 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1068 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1069 
1070 	spin_unlock(&xprt->transport_lock);
1071 	return 0;
1072 }
1073 
1074 #if defined(CONFIG_NFS_V4_1)
1075 /*
1076  * Obtains an rpc_rqst previously allocated and invokes the common
1077  * tcp read code to read the data.  The result is placed in the callback
1078  * queue.
1079  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1080  * connection and return -1.
1081  */
1082 static inline int xs_tcp_read_callback(struct rpc_xprt *xprt,
1083 				       struct xdr_skb_reader *desc)
1084 {
1085 	struct sock_xprt *transport =
1086 				container_of(xprt, struct sock_xprt, xprt);
1087 	struct rpc_rqst *req;
1088 
1089 	req = xprt_alloc_bc_request(xprt);
1090 	if (req == NULL) {
1091 		printk(KERN_WARNING "Callback slot table overflowed\n");
1092 		xprt_force_disconnect(xprt);
1093 		return -1;
1094 	}
1095 
1096 	req->rq_xid = transport->tcp_xid;
1097 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1098 	xs_tcp_read_common(xprt, desc, req);
1099 
1100 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) {
1101 		struct svc_serv *bc_serv = xprt->bc_serv;
1102 
1103 		/*
1104 		 * Add callback request to callback list.  The callback
1105 		 * service sleeps on the sv_cb_waitq waiting for new
1106 		 * requests.  Wake it up after adding enqueing the
1107 		 * request.
1108 		 */
1109 		dprintk("RPC:       add callback request to list\n");
1110 		spin_lock(&bc_serv->sv_cb_lock);
1111 		list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
1112 		spin_unlock(&bc_serv->sv_cb_lock);
1113 		wake_up(&bc_serv->sv_cb_waitq);
1114 	}
1115 
1116 	req->rq_private_buf.len = transport->tcp_copied;
1117 
1118 	return 0;
1119 }
1120 
1121 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1122 					struct xdr_skb_reader *desc)
1123 {
1124 	struct sock_xprt *transport =
1125 				container_of(xprt, struct sock_xprt, xprt);
1126 
1127 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1128 		xs_tcp_read_reply(xprt, desc) :
1129 		xs_tcp_read_callback(xprt, desc);
1130 }
1131 #else
1132 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1133 					struct xdr_skb_reader *desc)
1134 {
1135 	return xs_tcp_read_reply(xprt, desc);
1136 }
1137 #endif /* CONFIG_NFS_V4_1 */
1138 
1139 /*
1140  * Read data off the transport.  This can be either an RPC_CALL or an
1141  * RPC_REPLY.  Relay the processing to helper functions.
1142  */
1143 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1144 				    struct xdr_skb_reader *desc)
1145 {
1146 	struct sock_xprt *transport =
1147 				container_of(xprt, struct sock_xprt, xprt);
1148 
1149 	if (_xs_tcp_read_data(xprt, desc) == 0)
1150 		xs_tcp_check_fraghdr(transport);
1151 	else {
1152 		/*
1153 		 * The transport_lock protects the request handling.
1154 		 * There's no need to hold it to update the tcp_flags.
1155 		 */
1156 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1157 	}
1158 }
1159 
1160 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1161 {
1162 	size_t len;
1163 
1164 	len = transport->tcp_reclen - transport->tcp_offset;
1165 	if (len > desc->count)
1166 		len = desc->count;
1167 	desc->count -= len;
1168 	desc->offset += len;
1169 	transport->tcp_offset += len;
1170 	dprintk("RPC:       discarded %Zu bytes\n", len);
1171 	xs_tcp_check_fraghdr(transport);
1172 }
1173 
1174 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1175 {
1176 	struct rpc_xprt *xprt = rd_desc->arg.data;
1177 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1178 	struct xdr_skb_reader desc = {
1179 		.skb	= skb,
1180 		.offset	= offset,
1181 		.count	= len,
1182 	};
1183 
1184 	dprintk("RPC:       xs_tcp_data_recv started\n");
1185 	do {
1186 		/* Read in a new fragment marker if necessary */
1187 		/* Can we ever really expect to get completely empty fragments? */
1188 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1189 			xs_tcp_read_fraghdr(xprt, &desc);
1190 			continue;
1191 		}
1192 		/* Read in the xid if necessary */
1193 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1194 			xs_tcp_read_xid(transport, &desc);
1195 			continue;
1196 		}
1197 		/* Read in the call/reply flag */
1198 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1199 			xs_tcp_read_calldir(transport, &desc);
1200 			continue;
1201 		}
1202 		/* Read in the request data */
1203 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1204 			xs_tcp_read_data(xprt, &desc);
1205 			continue;
1206 		}
1207 		/* Skip over any trailing bytes on short reads */
1208 		xs_tcp_read_discard(transport, &desc);
1209 	} while (desc.count);
1210 	dprintk("RPC:       xs_tcp_data_recv done\n");
1211 	return len - desc.count;
1212 }
1213 
1214 /**
1215  * xs_tcp_data_ready - "data ready" callback for TCP sockets
1216  * @sk: socket with data to read
1217  * @bytes: how much data to read
1218  *
1219  */
1220 static void xs_tcp_data_ready(struct sock *sk, int bytes)
1221 {
1222 	struct rpc_xprt *xprt;
1223 	read_descriptor_t rd_desc;
1224 	int read;
1225 
1226 	dprintk("RPC:       xs_tcp_data_ready...\n");
1227 
1228 	read_lock(&sk->sk_callback_lock);
1229 	if (!(xprt = xprt_from_sock(sk)))
1230 		goto out;
1231 	if (xprt->shutdown)
1232 		goto out;
1233 
1234 	/* Any data means we had a useful conversation, so
1235 	 * the we don't need to delay the next reconnect
1236 	 */
1237 	if (xprt->reestablish_timeout)
1238 		xprt->reestablish_timeout = 0;
1239 
1240 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1241 	rd_desc.arg.data = xprt;
1242 	do {
1243 		rd_desc.count = 65536;
1244 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1245 	} while (read > 0);
1246 out:
1247 	read_unlock(&sk->sk_callback_lock);
1248 }
1249 
1250 /*
1251  * Do the equivalent of linger/linger2 handling for dealing with
1252  * broken servers that don't close the socket in a timely
1253  * fashion
1254  */
1255 static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt,
1256 		unsigned long timeout)
1257 {
1258 	struct sock_xprt *transport;
1259 
1260 	if (xprt_test_and_set_connecting(xprt))
1261 		return;
1262 	set_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1263 	transport = container_of(xprt, struct sock_xprt, xprt);
1264 	queue_delayed_work(rpciod_workqueue, &transport->connect_worker,
1265 			   timeout);
1266 }
1267 
1268 static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
1269 {
1270 	struct sock_xprt *transport;
1271 
1272 	transport = container_of(xprt, struct sock_xprt, xprt);
1273 
1274 	if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) ||
1275 	    !cancel_delayed_work(&transport->connect_worker))
1276 		return;
1277 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1278 	xprt_clear_connecting(xprt);
1279 }
1280 
1281 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
1282 {
1283 	smp_mb__before_clear_bit();
1284 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1285 	clear_bit(XPRT_CLOSING, &xprt->state);
1286 	smp_mb__after_clear_bit();
1287 	/* Mark transport as closed and wake up all pending tasks */
1288 	xprt_disconnect_done(xprt);
1289 }
1290 
1291 /**
1292  * xs_tcp_state_change - callback to handle TCP socket state changes
1293  * @sk: socket whose state has changed
1294  *
1295  */
1296 static void xs_tcp_state_change(struct sock *sk)
1297 {
1298 	struct rpc_xprt *xprt;
1299 
1300 	read_lock(&sk->sk_callback_lock);
1301 	if (!(xprt = xprt_from_sock(sk)))
1302 		goto out;
1303 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1304 	dprintk("RPC:       state %x conn %d dead %d zapped %d\n",
1305 			sk->sk_state, xprt_connected(xprt),
1306 			sock_flag(sk, SOCK_DEAD),
1307 			sock_flag(sk, SOCK_ZAPPED));
1308 
1309 	switch (sk->sk_state) {
1310 	case TCP_ESTABLISHED:
1311 		spin_lock_bh(&xprt->transport_lock);
1312 		if (!xprt_test_and_set_connected(xprt)) {
1313 			struct sock_xprt *transport = container_of(xprt,
1314 					struct sock_xprt, xprt);
1315 
1316 			/* Reset TCP record info */
1317 			transport->tcp_offset = 0;
1318 			transport->tcp_reclen = 0;
1319 			transport->tcp_copied = 0;
1320 			transport->tcp_flags =
1321 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1322 
1323 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1324 		}
1325 		spin_unlock_bh(&xprt->transport_lock);
1326 		break;
1327 	case TCP_FIN_WAIT1:
1328 		/* The client initiated a shutdown of the socket */
1329 		xprt->connect_cookie++;
1330 		xprt->reestablish_timeout = 0;
1331 		set_bit(XPRT_CLOSING, &xprt->state);
1332 		smp_mb__before_clear_bit();
1333 		clear_bit(XPRT_CONNECTED, &xprt->state);
1334 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1335 		smp_mb__after_clear_bit();
1336 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1337 		break;
1338 	case TCP_CLOSE_WAIT:
1339 		/* The server initiated a shutdown of the socket */
1340 		xprt_force_disconnect(xprt);
1341 	case TCP_SYN_SENT:
1342 		xprt->connect_cookie++;
1343 	case TCP_CLOSING:
1344 		/*
1345 		 * If the server closed down the connection, make sure that
1346 		 * we back off before reconnecting
1347 		 */
1348 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1349 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1350 		break;
1351 	case TCP_LAST_ACK:
1352 		set_bit(XPRT_CLOSING, &xprt->state);
1353 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1354 		smp_mb__before_clear_bit();
1355 		clear_bit(XPRT_CONNECTED, &xprt->state);
1356 		smp_mb__after_clear_bit();
1357 		break;
1358 	case TCP_CLOSE:
1359 		xs_tcp_cancel_linger_timeout(xprt);
1360 		xs_sock_mark_closed(xprt);
1361 	}
1362  out:
1363 	read_unlock(&sk->sk_callback_lock);
1364 }
1365 
1366 /**
1367  * xs_error_report - callback mainly for catching socket errors
1368  * @sk: socket
1369  */
1370 static void xs_error_report(struct sock *sk)
1371 {
1372 	struct rpc_xprt *xprt;
1373 
1374 	read_lock(&sk->sk_callback_lock);
1375 	if (!(xprt = xprt_from_sock(sk)))
1376 		goto out;
1377 	dprintk("RPC:       %s client %p...\n"
1378 			"RPC:       error %d\n",
1379 			__func__, xprt, sk->sk_err);
1380 	xprt_wake_pending_tasks(xprt, -EAGAIN);
1381 out:
1382 	read_unlock(&sk->sk_callback_lock);
1383 }
1384 
1385 static void xs_write_space(struct sock *sk)
1386 {
1387 	struct socket *sock;
1388 	struct rpc_xprt *xprt;
1389 
1390 	if (unlikely(!(sock = sk->sk_socket)))
1391 		return;
1392 	clear_bit(SOCK_NOSPACE, &sock->flags);
1393 
1394 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1395 		return;
1396 	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
1397 		return;
1398 
1399 	xprt_write_space(xprt);
1400 }
1401 
1402 /**
1403  * xs_udp_write_space - callback invoked when socket buffer space
1404  *                             becomes available
1405  * @sk: socket whose state has changed
1406  *
1407  * Called when more output buffer space is available for this socket.
1408  * We try not to wake our writers until they can make "significant"
1409  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1410  * with a bunch of small requests.
1411  */
1412 static void xs_udp_write_space(struct sock *sk)
1413 {
1414 	read_lock(&sk->sk_callback_lock);
1415 
1416 	/* from net/core/sock.c:sock_def_write_space */
1417 	if (sock_writeable(sk))
1418 		xs_write_space(sk);
1419 
1420 	read_unlock(&sk->sk_callback_lock);
1421 }
1422 
1423 /**
1424  * xs_tcp_write_space - callback invoked when socket buffer space
1425  *                             becomes available
1426  * @sk: socket whose state has changed
1427  *
1428  * Called when more output buffer space is available for this socket.
1429  * We try not to wake our writers until they can make "significant"
1430  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1431  * with a bunch of small requests.
1432  */
1433 static void xs_tcp_write_space(struct sock *sk)
1434 {
1435 	read_lock(&sk->sk_callback_lock);
1436 
1437 	/* from net/core/stream.c:sk_stream_write_space */
1438 	if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
1439 		xs_write_space(sk);
1440 
1441 	read_unlock(&sk->sk_callback_lock);
1442 }
1443 
1444 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1445 {
1446 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1447 	struct sock *sk = transport->inet;
1448 
1449 	if (transport->rcvsize) {
1450 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1451 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1452 	}
1453 	if (transport->sndsize) {
1454 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1455 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1456 		sk->sk_write_space(sk);
1457 	}
1458 }
1459 
1460 /**
1461  * xs_udp_set_buffer_size - set send and receive limits
1462  * @xprt: generic transport
1463  * @sndsize: requested size of send buffer, in bytes
1464  * @rcvsize: requested size of receive buffer, in bytes
1465  *
1466  * Set socket send and receive buffer size limits.
1467  */
1468 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1469 {
1470 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1471 
1472 	transport->sndsize = 0;
1473 	if (sndsize)
1474 		transport->sndsize = sndsize + 1024;
1475 	transport->rcvsize = 0;
1476 	if (rcvsize)
1477 		transport->rcvsize = rcvsize + 1024;
1478 
1479 	xs_udp_do_set_buffer_size(xprt);
1480 }
1481 
1482 /**
1483  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1484  * @task: task that timed out
1485  *
1486  * Adjust the congestion window after a retransmit timeout has occurred.
1487  */
1488 static void xs_udp_timer(struct rpc_task *task)
1489 {
1490 	xprt_adjust_cwnd(task, -ETIMEDOUT);
1491 }
1492 
1493 static unsigned short xs_get_random_port(void)
1494 {
1495 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1496 	unsigned short rand = (unsigned short) net_random() % range;
1497 	return rand + xprt_min_resvport;
1498 }
1499 
1500 /**
1501  * xs_set_port - reset the port number in the remote endpoint address
1502  * @xprt: generic transport
1503  * @port: new port number
1504  *
1505  */
1506 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1507 {
1508 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1509 
1510 	rpc_set_port(xs_addr(xprt), port);
1511 	xs_update_peer_port(xprt);
1512 }
1513 
1514 static unsigned short xs_get_srcport(struct sock_xprt *transport, struct socket *sock)
1515 {
1516 	unsigned short port = transport->srcport;
1517 
1518 	if (port == 0 && transport->xprt.resvport)
1519 		port = xs_get_random_port();
1520 	return port;
1521 }
1522 
1523 static unsigned short xs_next_srcport(struct sock_xprt *transport, struct socket *sock, unsigned short port)
1524 {
1525 	if (transport->srcport != 0)
1526 		transport->srcport = 0;
1527 	if (!transport->xprt.resvport)
1528 		return 0;
1529 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1530 		return xprt_max_resvport;
1531 	return --port;
1532 }
1533 
1534 static int xs_bind4(struct sock_xprt *transport, struct socket *sock)
1535 {
1536 	struct sockaddr_in myaddr = {
1537 		.sin_family = AF_INET,
1538 	};
1539 	struct sockaddr_in *sa;
1540 	int err, nloop = 0;
1541 	unsigned short port = xs_get_srcport(transport, sock);
1542 	unsigned short last;
1543 
1544 	sa = (struct sockaddr_in *)&transport->srcaddr;
1545 	myaddr.sin_addr = sa->sin_addr;
1546 	do {
1547 		myaddr.sin_port = htons(port);
1548 		err = kernel_bind(sock, (struct sockaddr *) &myaddr,
1549 						sizeof(myaddr));
1550 		if (port == 0)
1551 			break;
1552 		if (err == 0) {
1553 			transport->srcport = port;
1554 			break;
1555 		}
1556 		last = port;
1557 		port = xs_next_srcport(transport, sock, port);
1558 		if (port > last)
1559 			nloop++;
1560 	} while (err == -EADDRINUSE && nloop != 2);
1561 	dprintk("RPC:       %s %pI4:%u: %s (%d)\n",
1562 			__func__, &myaddr.sin_addr,
1563 			port, err ? "failed" : "ok", err);
1564 	return err;
1565 }
1566 
1567 static int xs_bind6(struct sock_xprt *transport, struct socket *sock)
1568 {
1569 	struct sockaddr_in6 myaddr = {
1570 		.sin6_family = AF_INET6,
1571 	};
1572 	struct sockaddr_in6 *sa;
1573 	int err, nloop = 0;
1574 	unsigned short port = xs_get_srcport(transport, sock);
1575 	unsigned short last;
1576 
1577 	sa = (struct sockaddr_in6 *)&transport->srcaddr;
1578 	myaddr.sin6_addr = sa->sin6_addr;
1579 	do {
1580 		myaddr.sin6_port = htons(port);
1581 		err = kernel_bind(sock, (struct sockaddr *) &myaddr,
1582 						sizeof(myaddr));
1583 		if (port == 0)
1584 			break;
1585 		if (err == 0) {
1586 			transport->srcport = port;
1587 			break;
1588 		}
1589 		last = port;
1590 		port = xs_next_srcport(transport, sock, port);
1591 		if (port > last)
1592 			nloop++;
1593 	} while (err == -EADDRINUSE && nloop != 2);
1594 	dprintk("RPC:       xs_bind6 %pI6:%u: %s (%d)\n",
1595 		&myaddr.sin6_addr, port, err ? "failed" : "ok", err);
1596 	return err;
1597 }
1598 
1599 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1600 static struct lock_class_key xs_key[2];
1601 static struct lock_class_key xs_slock_key[2];
1602 
1603 static inline void xs_reclassify_socket4(struct socket *sock)
1604 {
1605 	struct sock *sk = sock->sk;
1606 
1607 	BUG_ON(sock_owned_by_user(sk));
1608 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1609 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1610 }
1611 
1612 static inline void xs_reclassify_socket6(struct socket *sock)
1613 {
1614 	struct sock *sk = sock->sk;
1615 
1616 	BUG_ON(sock_owned_by_user(sk));
1617 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1618 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1619 }
1620 #else
1621 static inline void xs_reclassify_socket4(struct socket *sock)
1622 {
1623 }
1624 
1625 static inline void xs_reclassify_socket6(struct socket *sock)
1626 {
1627 }
1628 #endif
1629 
1630 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1631 {
1632 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1633 
1634 	if (!transport->inet) {
1635 		struct sock *sk = sock->sk;
1636 
1637 		write_lock_bh(&sk->sk_callback_lock);
1638 
1639 		xs_save_old_callbacks(transport, sk);
1640 
1641 		sk->sk_user_data = xprt;
1642 		sk->sk_data_ready = xs_udp_data_ready;
1643 		sk->sk_write_space = xs_udp_write_space;
1644 		sk->sk_error_report = xs_error_report;
1645 		sk->sk_no_check = UDP_CSUM_NORCV;
1646 		sk->sk_allocation = GFP_ATOMIC;
1647 
1648 		xprt_set_connected(xprt);
1649 
1650 		/* Reset to new socket */
1651 		transport->sock = sock;
1652 		transport->inet = sk;
1653 
1654 		write_unlock_bh(&sk->sk_callback_lock);
1655 	}
1656 	xs_udp_do_set_buffer_size(xprt);
1657 }
1658 
1659 /**
1660  * xs_udp_connect_worker4 - set up a UDP socket
1661  * @work: RPC transport to connect
1662  *
1663  * Invoked by a work queue tasklet.
1664  */
1665 static void xs_udp_connect_worker4(struct work_struct *work)
1666 {
1667 	struct sock_xprt *transport =
1668 		container_of(work, struct sock_xprt, connect_worker.work);
1669 	struct rpc_xprt *xprt = &transport->xprt;
1670 	struct socket *sock = transport->sock;
1671 	int err, status = -EIO;
1672 
1673 	if (xprt->shutdown)
1674 		goto out;
1675 
1676 	/* Start by resetting any existing state */
1677 	xs_reset_transport(transport);
1678 
1679 	err = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
1680 	if (err < 0) {
1681 		dprintk("RPC:       can't create UDP transport socket (%d).\n", -err);
1682 		goto out;
1683 	}
1684 	xs_reclassify_socket4(sock);
1685 
1686 	if (xs_bind4(transport, sock)) {
1687 		sock_release(sock);
1688 		goto out;
1689 	}
1690 
1691 	dprintk("RPC:       worker connecting xprt %p via %s to "
1692 				"%s (port %s)\n", xprt,
1693 			xprt->address_strings[RPC_DISPLAY_PROTO],
1694 			xprt->address_strings[RPC_DISPLAY_ADDR],
1695 			xprt->address_strings[RPC_DISPLAY_PORT]);
1696 
1697 	xs_udp_finish_connecting(xprt, sock);
1698 	status = 0;
1699 out:
1700 	xprt_clear_connecting(xprt);
1701 	xprt_wake_pending_tasks(xprt, status);
1702 }
1703 
1704 /**
1705  * xs_udp_connect_worker6 - set up a UDP socket
1706  * @work: RPC transport to connect
1707  *
1708  * Invoked by a work queue tasklet.
1709  */
1710 static void xs_udp_connect_worker6(struct work_struct *work)
1711 {
1712 	struct sock_xprt *transport =
1713 		container_of(work, struct sock_xprt, connect_worker.work);
1714 	struct rpc_xprt *xprt = &transport->xprt;
1715 	struct socket *sock = transport->sock;
1716 	int err, status = -EIO;
1717 
1718 	if (xprt->shutdown)
1719 		goto out;
1720 
1721 	/* Start by resetting any existing state */
1722 	xs_reset_transport(transport);
1723 
1724 	err = sock_create_kern(PF_INET6, SOCK_DGRAM, IPPROTO_UDP, &sock);
1725 	if (err < 0) {
1726 		dprintk("RPC:       can't create UDP transport socket (%d).\n", -err);
1727 		goto out;
1728 	}
1729 	xs_reclassify_socket6(sock);
1730 
1731 	if (xs_bind6(transport, sock) < 0) {
1732 		sock_release(sock);
1733 		goto out;
1734 	}
1735 
1736 	dprintk("RPC:       worker connecting xprt %p via %s to "
1737 				"%s (port %s)\n", xprt,
1738 			xprt->address_strings[RPC_DISPLAY_PROTO],
1739 			xprt->address_strings[RPC_DISPLAY_ADDR],
1740 			xprt->address_strings[RPC_DISPLAY_PORT]);
1741 
1742 	xs_udp_finish_connecting(xprt, sock);
1743 	status = 0;
1744 out:
1745 	xprt_clear_connecting(xprt);
1746 	xprt_wake_pending_tasks(xprt, status);
1747 }
1748 
1749 /*
1750  * We need to preserve the port number so the reply cache on the server can
1751  * find our cached RPC replies when we get around to reconnecting.
1752  */
1753 static void xs_abort_connection(struct rpc_xprt *xprt, struct sock_xprt *transport)
1754 {
1755 	int result;
1756 	struct sockaddr any;
1757 
1758 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", xprt);
1759 
1760 	/*
1761 	 * Disconnect the transport socket by doing a connect operation
1762 	 * with AF_UNSPEC.  This should return immediately...
1763 	 */
1764 	memset(&any, 0, sizeof(any));
1765 	any.sa_family = AF_UNSPEC;
1766 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
1767 	if (!result)
1768 		xs_sock_mark_closed(xprt);
1769 	else
1770 		dprintk("RPC:       AF_UNSPEC connect return code %d\n",
1771 				result);
1772 }
1773 
1774 static void xs_tcp_reuse_connection(struct rpc_xprt *xprt, struct sock_xprt *transport)
1775 {
1776 	unsigned int state = transport->inet->sk_state;
1777 
1778 	if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED)
1779 		return;
1780 	if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT))
1781 		return;
1782 	xs_abort_connection(xprt, transport);
1783 }
1784 
1785 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1786 {
1787 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1788 
1789 	if (!transport->inet) {
1790 		struct sock *sk = sock->sk;
1791 
1792 		write_lock_bh(&sk->sk_callback_lock);
1793 
1794 		xs_save_old_callbacks(transport, sk);
1795 
1796 		sk->sk_user_data = xprt;
1797 		sk->sk_data_ready = xs_tcp_data_ready;
1798 		sk->sk_state_change = xs_tcp_state_change;
1799 		sk->sk_write_space = xs_tcp_write_space;
1800 		sk->sk_error_report = xs_error_report;
1801 		sk->sk_allocation = GFP_ATOMIC;
1802 
1803 		/* socket options */
1804 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
1805 		sock_reset_flag(sk, SOCK_LINGER);
1806 		tcp_sk(sk)->linger2 = 0;
1807 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
1808 
1809 		xprt_clear_connected(xprt);
1810 
1811 		/* Reset to new socket */
1812 		transport->sock = sock;
1813 		transport->inet = sk;
1814 
1815 		write_unlock_bh(&sk->sk_callback_lock);
1816 	}
1817 
1818 	if (!xprt_bound(xprt))
1819 		return -ENOTCONN;
1820 
1821 	/* Tell the socket layer to start connecting... */
1822 	xprt->stat.connect_count++;
1823 	xprt->stat.connect_start = jiffies;
1824 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
1825 }
1826 
1827 /**
1828  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
1829  * @xprt: RPC transport to connect
1830  * @transport: socket transport to connect
1831  * @create_sock: function to create a socket of the correct type
1832  *
1833  * Invoked by a work queue tasklet.
1834  */
1835 static void xs_tcp_setup_socket(struct rpc_xprt *xprt,
1836 		struct sock_xprt *transport,
1837 		struct socket *(*create_sock)(struct rpc_xprt *,
1838 			struct sock_xprt *))
1839 {
1840 	struct socket *sock = transport->sock;
1841 	int status = -EIO;
1842 
1843 	if (xprt->shutdown)
1844 		goto out;
1845 
1846 	if (!sock) {
1847 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1848 		sock = create_sock(xprt, transport);
1849 		if (IS_ERR(sock)) {
1850 			status = PTR_ERR(sock);
1851 			goto out;
1852 		}
1853 	} else {
1854 		int abort_and_exit;
1855 
1856 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
1857 				&xprt->state);
1858 		/* "close" the socket, preserving the local port */
1859 		xs_tcp_reuse_connection(xprt, transport);
1860 
1861 		if (abort_and_exit)
1862 			goto out_eagain;
1863 	}
1864 
1865 	dprintk("RPC:       worker connecting xprt %p via %s to "
1866 				"%s (port %s)\n", xprt,
1867 			xprt->address_strings[RPC_DISPLAY_PROTO],
1868 			xprt->address_strings[RPC_DISPLAY_ADDR],
1869 			xprt->address_strings[RPC_DISPLAY_PORT]);
1870 
1871 	status = xs_tcp_finish_connecting(xprt, sock);
1872 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
1873 			xprt, -status, xprt_connected(xprt),
1874 			sock->sk->sk_state);
1875 	switch (status) {
1876 	default:
1877 		printk("%s: connect returned unhandled error %d\n",
1878 			__func__, status);
1879 	case -EADDRNOTAVAIL:
1880 		/* We're probably in TIME_WAIT. Get rid of existing socket,
1881 		 * and retry
1882 		 */
1883 		set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1884 		xprt_force_disconnect(xprt);
1885 		break;
1886 	case -ECONNREFUSED:
1887 	case -ECONNRESET:
1888 	case -ENETUNREACH:
1889 		/* retry with existing socket, after a delay */
1890 	case 0:
1891 	case -EINPROGRESS:
1892 	case -EALREADY:
1893 		xprt_clear_connecting(xprt);
1894 		return;
1895 	case -EINVAL:
1896 		/* Happens, for instance, if the user specified a link
1897 		 * local IPv6 address without a scope-id.
1898 		 */
1899 		goto out;
1900 	}
1901 out_eagain:
1902 	status = -EAGAIN;
1903 out:
1904 	xprt_clear_connecting(xprt);
1905 	xprt_wake_pending_tasks(xprt, status);
1906 }
1907 
1908 static struct socket *xs_create_tcp_sock4(struct rpc_xprt *xprt,
1909 		struct sock_xprt *transport)
1910 {
1911 	struct socket *sock;
1912 	int err;
1913 
1914 	/* start from scratch */
1915 	err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1916 	if (err < 0) {
1917 		dprintk("RPC:       can't create TCP transport socket (%d).\n",
1918 				-err);
1919 		goto out_err;
1920 	}
1921 	xs_reclassify_socket4(sock);
1922 
1923 	if (xs_bind4(transport, sock) < 0) {
1924 		sock_release(sock);
1925 		goto out_err;
1926 	}
1927 	return sock;
1928 out_err:
1929 	return ERR_PTR(-EIO);
1930 }
1931 
1932 /**
1933  * xs_tcp_connect_worker4 - connect a TCP socket to a remote endpoint
1934  * @work: RPC transport to connect
1935  *
1936  * Invoked by a work queue tasklet.
1937  */
1938 static void xs_tcp_connect_worker4(struct work_struct *work)
1939 {
1940 	struct sock_xprt *transport =
1941 		container_of(work, struct sock_xprt, connect_worker.work);
1942 	struct rpc_xprt *xprt = &transport->xprt;
1943 
1944 	xs_tcp_setup_socket(xprt, transport, xs_create_tcp_sock4);
1945 }
1946 
1947 static struct socket *xs_create_tcp_sock6(struct rpc_xprt *xprt,
1948 		struct sock_xprt *transport)
1949 {
1950 	struct socket *sock;
1951 	int err;
1952 
1953 	/* start from scratch */
1954 	err = sock_create_kern(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &sock);
1955 	if (err < 0) {
1956 		dprintk("RPC:       can't create TCP transport socket (%d).\n",
1957 				-err);
1958 		goto out_err;
1959 	}
1960 	xs_reclassify_socket6(sock);
1961 
1962 	if (xs_bind6(transport, sock) < 0) {
1963 		sock_release(sock);
1964 		goto out_err;
1965 	}
1966 	return sock;
1967 out_err:
1968 	return ERR_PTR(-EIO);
1969 }
1970 
1971 /**
1972  * xs_tcp_connect_worker6 - connect a TCP socket to a remote endpoint
1973  * @work: RPC transport to connect
1974  *
1975  * Invoked by a work queue tasklet.
1976  */
1977 static void xs_tcp_connect_worker6(struct work_struct *work)
1978 {
1979 	struct sock_xprt *transport =
1980 		container_of(work, struct sock_xprt, connect_worker.work);
1981 	struct rpc_xprt *xprt = &transport->xprt;
1982 
1983 	xs_tcp_setup_socket(xprt, transport, xs_create_tcp_sock6);
1984 }
1985 
1986 /**
1987  * xs_connect - connect a socket to a remote endpoint
1988  * @task: address of RPC task that manages state of connect request
1989  *
1990  * TCP: If the remote end dropped the connection, delay reconnecting.
1991  *
1992  * UDP socket connects are synchronous, but we use a work queue anyway
1993  * to guarantee that even unprivileged user processes can set up a
1994  * socket on a privileged port.
1995  *
1996  * If a UDP socket connect fails, the delay behavior here prevents
1997  * retry floods (hard mounts).
1998  */
1999 static void xs_connect(struct rpc_task *task)
2000 {
2001 	struct rpc_xprt *xprt = task->tk_xprt;
2002 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2003 
2004 	if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) {
2005 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2006 				"seconds\n",
2007 				xprt, xprt->reestablish_timeout / HZ);
2008 		queue_delayed_work(rpciod_workqueue,
2009 				   &transport->connect_worker,
2010 				   xprt->reestablish_timeout);
2011 		xprt->reestablish_timeout <<= 1;
2012 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2013 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2014 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
2015 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
2016 	} else {
2017 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2018 		queue_delayed_work(rpciod_workqueue,
2019 				   &transport->connect_worker, 0);
2020 	}
2021 }
2022 
2023 /**
2024  * xs_udp_print_stats - display UDP socket-specifc stats
2025  * @xprt: rpc_xprt struct containing statistics
2026  * @seq: output file
2027  *
2028  */
2029 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2030 {
2031 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2032 
2033 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %Lu %Lu\n",
2034 			transport->srcport,
2035 			xprt->stat.bind_count,
2036 			xprt->stat.sends,
2037 			xprt->stat.recvs,
2038 			xprt->stat.bad_xids,
2039 			xprt->stat.req_u,
2040 			xprt->stat.bklog_u);
2041 }
2042 
2043 /**
2044  * xs_tcp_print_stats - display TCP socket-specifc stats
2045  * @xprt: rpc_xprt struct containing statistics
2046  * @seq: output file
2047  *
2048  */
2049 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2050 {
2051 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2052 	long idle_time = 0;
2053 
2054 	if (xprt_connected(xprt))
2055 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2056 
2057 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu %Lu %Lu\n",
2058 			transport->srcport,
2059 			xprt->stat.bind_count,
2060 			xprt->stat.connect_count,
2061 			xprt->stat.connect_time,
2062 			idle_time,
2063 			xprt->stat.sends,
2064 			xprt->stat.recvs,
2065 			xprt->stat.bad_xids,
2066 			xprt->stat.req_u,
2067 			xprt->stat.bklog_u);
2068 }
2069 
2070 /*
2071  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2072  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2073  * to use the server side send routines.
2074  */
2075 static void *bc_malloc(struct rpc_task *task, size_t size)
2076 {
2077 	struct page *page;
2078 	struct rpc_buffer *buf;
2079 
2080 	BUG_ON(size > PAGE_SIZE - sizeof(struct rpc_buffer));
2081 	page = alloc_page(GFP_KERNEL);
2082 
2083 	if (!page)
2084 		return NULL;
2085 
2086 	buf = page_address(page);
2087 	buf->len = PAGE_SIZE;
2088 
2089 	return buf->data;
2090 }
2091 
2092 /*
2093  * Free the space allocated in the bc_alloc routine
2094  */
2095 static void bc_free(void *buffer)
2096 {
2097 	struct rpc_buffer *buf;
2098 
2099 	if (!buffer)
2100 		return;
2101 
2102 	buf = container_of(buffer, struct rpc_buffer, data);
2103 	free_page((unsigned long)buf);
2104 }
2105 
2106 /*
2107  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2108  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2109  */
2110 static int bc_sendto(struct rpc_rqst *req)
2111 {
2112 	int len;
2113 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2114 	struct rpc_xprt *xprt = req->rq_xprt;
2115 	struct sock_xprt *transport =
2116 				container_of(xprt, struct sock_xprt, xprt);
2117 	struct socket *sock = transport->sock;
2118 	unsigned long headoff;
2119 	unsigned long tailoff;
2120 
2121 	/*
2122 	 * Set up the rpc header and record marker stuff
2123 	 */
2124 	xs_encode_tcp_record_marker(xbufp);
2125 
2126 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2127 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2128 	len = svc_send_common(sock, xbufp,
2129 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2130 			      xbufp->tail[0].iov_base, tailoff);
2131 
2132 	if (len != xbufp->len) {
2133 		printk(KERN_NOTICE "Error sending entire callback!\n");
2134 		len = -EAGAIN;
2135 	}
2136 
2137 	return len;
2138 }
2139 
2140 /*
2141  * The send routine. Borrows from svc_send
2142  */
2143 static int bc_send_request(struct rpc_task *task)
2144 {
2145 	struct rpc_rqst *req = task->tk_rqstp;
2146 	struct svc_xprt	*xprt;
2147 	struct svc_sock         *svsk;
2148 	u32                     len;
2149 
2150 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2151 	/*
2152 	 * Get the server socket associated with this callback xprt
2153 	 */
2154 	xprt = req->rq_xprt->bc_xprt;
2155 	svsk = container_of(xprt, struct svc_sock, sk_xprt);
2156 
2157 	/*
2158 	 * Grab the mutex to serialize data as the connection is shared
2159 	 * with the fore channel
2160 	 */
2161 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2162 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2163 		if (!mutex_trylock(&xprt->xpt_mutex))
2164 			return -EAGAIN;
2165 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2166 	}
2167 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2168 		len = -ENOTCONN;
2169 	else
2170 		len = bc_sendto(req);
2171 	mutex_unlock(&xprt->xpt_mutex);
2172 
2173 	if (len > 0)
2174 		len = 0;
2175 
2176 	return len;
2177 }
2178 
2179 /*
2180  * The close routine. Since this is client initiated, we do nothing
2181  */
2182 
2183 static void bc_close(struct rpc_xprt *xprt)
2184 {
2185 	return;
2186 }
2187 
2188 /*
2189  * The xprt destroy routine. Again, because this connection is client
2190  * initiated, we do nothing
2191  */
2192 
2193 static void bc_destroy(struct rpc_xprt *xprt)
2194 {
2195 	return;
2196 }
2197 
2198 static struct rpc_xprt_ops xs_udp_ops = {
2199 	.set_buffer_size	= xs_udp_set_buffer_size,
2200 	.reserve_xprt		= xprt_reserve_xprt_cong,
2201 	.release_xprt		= xprt_release_xprt_cong,
2202 	.rpcbind		= rpcb_getport_async,
2203 	.set_port		= xs_set_port,
2204 	.connect		= xs_connect,
2205 	.buf_alloc		= rpc_malloc,
2206 	.buf_free		= rpc_free,
2207 	.send_request		= xs_udp_send_request,
2208 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2209 	.timer			= xs_udp_timer,
2210 	.release_request	= xprt_release_rqst_cong,
2211 	.close			= xs_close,
2212 	.destroy		= xs_destroy,
2213 	.print_stats		= xs_udp_print_stats,
2214 };
2215 
2216 static struct rpc_xprt_ops xs_tcp_ops = {
2217 	.reserve_xprt		= xprt_reserve_xprt,
2218 	.release_xprt		= xs_tcp_release_xprt,
2219 	.rpcbind		= rpcb_getport_async,
2220 	.set_port		= xs_set_port,
2221 	.connect		= xs_connect,
2222 	.buf_alloc		= rpc_malloc,
2223 	.buf_free		= rpc_free,
2224 	.send_request		= xs_tcp_send_request,
2225 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2226 	.close			= xs_tcp_close,
2227 	.destroy		= xs_destroy,
2228 	.print_stats		= xs_tcp_print_stats,
2229 };
2230 
2231 /*
2232  * The rpc_xprt_ops for the server backchannel
2233  */
2234 
2235 static struct rpc_xprt_ops bc_tcp_ops = {
2236 	.reserve_xprt		= xprt_reserve_xprt,
2237 	.release_xprt		= xprt_release_xprt,
2238 	.buf_alloc		= bc_malloc,
2239 	.buf_free		= bc_free,
2240 	.send_request		= bc_send_request,
2241 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2242 	.close			= bc_close,
2243 	.destroy		= bc_destroy,
2244 	.print_stats		= xs_tcp_print_stats,
2245 };
2246 
2247 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2248 				      unsigned int slot_table_size)
2249 {
2250 	struct rpc_xprt *xprt;
2251 	struct sock_xprt *new;
2252 
2253 	if (args->addrlen > sizeof(xprt->addr)) {
2254 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2255 		return ERR_PTR(-EBADF);
2256 	}
2257 
2258 	new = kzalloc(sizeof(*new), GFP_KERNEL);
2259 	if (new == NULL) {
2260 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2261 				"rpc_xprt\n");
2262 		return ERR_PTR(-ENOMEM);
2263 	}
2264 	xprt = &new->xprt;
2265 
2266 	xprt->max_reqs = slot_table_size;
2267 	xprt->slot = kcalloc(xprt->max_reqs, sizeof(struct rpc_rqst), GFP_KERNEL);
2268 	if (xprt->slot == NULL) {
2269 		kfree(xprt);
2270 		dprintk("RPC:       xs_setup_xprt: couldn't allocate slot "
2271 				"table\n");
2272 		return ERR_PTR(-ENOMEM);
2273 	}
2274 
2275 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2276 	xprt->addrlen = args->addrlen;
2277 	if (args->srcaddr)
2278 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2279 
2280 	return xprt;
2281 }
2282 
2283 static const struct rpc_timeout xs_udp_default_timeout = {
2284 	.to_initval = 5 * HZ,
2285 	.to_maxval = 30 * HZ,
2286 	.to_increment = 5 * HZ,
2287 	.to_retries = 5,
2288 };
2289 
2290 /**
2291  * xs_setup_udp - Set up transport to use a UDP socket
2292  * @args: rpc transport creation arguments
2293  *
2294  */
2295 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2296 {
2297 	struct sockaddr *addr = args->dstaddr;
2298 	struct rpc_xprt *xprt;
2299 	struct sock_xprt *transport;
2300 
2301 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries);
2302 	if (IS_ERR(xprt))
2303 		return xprt;
2304 	transport = container_of(xprt, struct sock_xprt, xprt);
2305 
2306 	xprt->prot = IPPROTO_UDP;
2307 	xprt->tsh_size = 0;
2308 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2309 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2310 
2311 	xprt->bind_timeout = XS_BIND_TO;
2312 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2313 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2314 
2315 	xprt->ops = &xs_udp_ops;
2316 
2317 	xprt->timeout = &xs_udp_default_timeout;
2318 
2319 	switch (addr->sa_family) {
2320 	case AF_INET:
2321 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2322 			xprt_set_bound(xprt);
2323 
2324 		INIT_DELAYED_WORK(&transport->connect_worker,
2325 					xs_udp_connect_worker4);
2326 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2327 		break;
2328 	case AF_INET6:
2329 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2330 			xprt_set_bound(xprt);
2331 
2332 		INIT_DELAYED_WORK(&transport->connect_worker,
2333 					xs_udp_connect_worker6);
2334 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2335 		break;
2336 	default:
2337 		kfree(xprt);
2338 		return ERR_PTR(-EAFNOSUPPORT);
2339 	}
2340 
2341 	if (xprt_bound(xprt))
2342 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2343 				xprt->address_strings[RPC_DISPLAY_ADDR],
2344 				xprt->address_strings[RPC_DISPLAY_PORT],
2345 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2346 	else
2347 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2348 				xprt->address_strings[RPC_DISPLAY_ADDR],
2349 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2350 
2351 	if (try_module_get(THIS_MODULE))
2352 		return xprt;
2353 
2354 	kfree(xprt->slot);
2355 	kfree(xprt);
2356 	return ERR_PTR(-EINVAL);
2357 }
2358 
2359 static const struct rpc_timeout xs_tcp_default_timeout = {
2360 	.to_initval = 60 * HZ,
2361 	.to_maxval = 60 * HZ,
2362 	.to_retries = 2,
2363 };
2364 
2365 /**
2366  * xs_setup_tcp - Set up transport to use a TCP socket
2367  * @args: rpc transport creation arguments
2368  *
2369  */
2370 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2371 {
2372 	struct sockaddr *addr = args->dstaddr;
2373 	struct rpc_xprt *xprt;
2374 	struct sock_xprt *transport;
2375 
2376 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
2377 	if (IS_ERR(xprt))
2378 		return xprt;
2379 	transport = container_of(xprt, struct sock_xprt, xprt);
2380 
2381 	xprt->prot = IPPROTO_TCP;
2382 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2383 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2384 
2385 	xprt->bind_timeout = XS_BIND_TO;
2386 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2387 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2388 
2389 	xprt->ops = &xs_tcp_ops;
2390 	xprt->timeout = &xs_tcp_default_timeout;
2391 
2392 	switch (addr->sa_family) {
2393 	case AF_INET:
2394 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2395 			xprt_set_bound(xprt);
2396 
2397 		INIT_DELAYED_WORK(&transport->connect_worker,
2398 					xs_tcp_connect_worker4);
2399 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
2400 		break;
2401 	case AF_INET6:
2402 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2403 			xprt_set_bound(xprt);
2404 
2405 		INIT_DELAYED_WORK(&transport->connect_worker,
2406 					xs_tcp_connect_worker6);
2407 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
2408 		break;
2409 	default:
2410 		kfree(xprt);
2411 		return ERR_PTR(-EAFNOSUPPORT);
2412 	}
2413 
2414 	if (xprt_bound(xprt))
2415 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2416 				xprt->address_strings[RPC_DISPLAY_ADDR],
2417 				xprt->address_strings[RPC_DISPLAY_PORT],
2418 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2419 	else
2420 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2421 				xprt->address_strings[RPC_DISPLAY_ADDR],
2422 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2423 
2424 
2425 	if (try_module_get(THIS_MODULE))
2426 		return xprt;
2427 
2428 	kfree(xprt->slot);
2429 	kfree(xprt);
2430 	return ERR_PTR(-EINVAL);
2431 }
2432 
2433 /**
2434  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
2435  * @args: rpc transport creation arguments
2436  *
2437  */
2438 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
2439 {
2440 	struct sockaddr *addr = args->dstaddr;
2441 	struct rpc_xprt *xprt;
2442 	struct sock_xprt *transport;
2443 	struct svc_sock *bc_sock;
2444 
2445 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
2446 	if (IS_ERR(xprt))
2447 		return xprt;
2448 	transport = container_of(xprt, struct sock_xprt, xprt);
2449 
2450 	xprt->prot = IPPROTO_TCP;
2451 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2452 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2453 	xprt->timeout = &xs_tcp_default_timeout;
2454 
2455 	/* backchannel */
2456 	xprt_set_bound(xprt);
2457 	xprt->bind_timeout = 0;
2458 	xprt->reestablish_timeout = 0;
2459 	xprt->idle_timeout = 0;
2460 
2461 	/*
2462 	 * The backchannel uses the same socket connection as the
2463 	 * forechannel
2464 	 */
2465 	xprt->bc_xprt = args->bc_xprt;
2466 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
2467 	bc_sock->sk_bc_xprt = xprt;
2468 	transport->sock = bc_sock->sk_sock;
2469 	transport->inet = bc_sock->sk_sk;
2470 
2471 	xprt->ops = &bc_tcp_ops;
2472 
2473 	switch (addr->sa_family) {
2474 	case AF_INET:
2475 		xs_format_peer_addresses(xprt, "tcp",
2476 					 RPCBIND_NETID_TCP);
2477 		break;
2478 	case AF_INET6:
2479 		xs_format_peer_addresses(xprt, "tcp",
2480 				   RPCBIND_NETID_TCP6);
2481 		break;
2482 	default:
2483 		kfree(xprt);
2484 		return ERR_PTR(-EAFNOSUPPORT);
2485 	}
2486 
2487 	if (xprt_bound(xprt))
2488 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2489 				xprt->address_strings[RPC_DISPLAY_ADDR],
2490 				xprt->address_strings[RPC_DISPLAY_PORT],
2491 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2492 	else
2493 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2494 				xprt->address_strings[RPC_DISPLAY_ADDR],
2495 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2496 
2497 	/*
2498 	 * Since we don't want connections for the backchannel, we set
2499 	 * the xprt status to connected
2500 	 */
2501 	xprt_set_connected(xprt);
2502 
2503 
2504 	if (try_module_get(THIS_MODULE))
2505 		return xprt;
2506 	kfree(xprt->slot);
2507 	kfree(xprt);
2508 	return ERR_PTR(-EINVAL);
2509 }
2510 
2511 static struct xprt_class	xs_udp_transport = {
2512 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
2513 	.name		= "udp",
2514 	.owner		= THIS_MODULE,
2515 	.ident		= XPRT_TRANSPORT_UDP,
2516 	.setup		= xs_setup_udp,
2517 };
2518 
2519 static struct xprt_class	xs_tcp_transport = {
2520 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
2521 	.name		= "tcp",
2522 	.owner		= THIS_MODULE,
2523 	.ident		= XPRT_TRANSPORT_TCP,
2524 	.setup		= xs_setup_tcp,
2525 };
2526 
2527 static struct xprt_class	xs_bc_tcp_transport = {
2528 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
2529 	.name		= "tcp NFSv4.1 backchannel",
2530 	.owner		= THIS_MODULE,
2531 	.ident		= XPRT_TRANSPORT_BC_TCP,
2532 	.setup		= xs_setup_bc_tcp,
2533 };
2534 
2535 /**
2536  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
2537  *
2538  */
2539 int init_socket_xprt(void)
2540 {
2541 #ifdef RPC_DEBUG
2542 	if (!sunrpc_table_header)
2543 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
2544 #endif
2545 
2546 	xprt_register_transport(&xs_udp_transport);
2547 	xprt_register_transport(&xs_tcp_transport);
2548 	xprt_register_transport(&xs_bc_tcp_transport);
2549 
2550 	return 0;
2551 }
2552 
2553 /**
2554  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
2555  *
2556  */
2557 void cleanup_socket_xprt(void)
2558 {
2559 #ifdef RPC_DEBUG
2560 	if (sunrpc_table_header) {
2561 		unregister_sysctl_table(sunrpc_table_header);
2562 		sunrpc_table_header = NULL;
2563 	}
2564 #endif
2565 
2566 	xprt_unregister_transport(&xs_udp_transport);
2567 	xprt_unregister_transport(&xs_tcp_transport);
2568 	xprt_unregister_transport(&xs_bc_tcp_transport);
2569 }
2570 
2571 static int param_set_uint_minmax(const char *val, struct kernel_param *kp,
2572 		unsigned int min, unsigned int max)
2573 {
2574 	unsigned long num;
2575 	int ret;
2576 
2577 	if (!val)
2578 		return -EINVAL;
2579 	ret = strict_strtoul(val, 0, &num);
2580 	if (ret == -EINVAL || num < min || num > max)
2581 		return -EINVAL;
2582 	*((unsigned int *)kp->arg) = num;
2583 	return 0;
2584 }
2585 
2586 static int param_set_portnr(const char *val, struct kernel_param *kp)
2587 {
2588 	return param_set_uint_minmax(val, kp,
2589 			RPC_MIN_RESVPORT,
2590 			RPC_MAX_RESVPORT);
2591 }
2592 
2593 static int param_get_portnr(char *buffer, struct kernel_param *kp)
2594 {
2595 	return param_get_uint(buffer, kp);
2596 }
2597 #define param_check_portnr(name, p) \
2598 	__param_check(name, p, unsigned int);
2599 
2600 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
2601 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
2602 
2603 static int param_set_slot_table_size(const char *val, struct kernel_param *kp)
2604 {
2605 	return param_set_uint_minmax(val, kp,
2606 			RPC_MIN_SLOT_TABLE,
2607 			RPC_MAX_SLOT_TABLE);
2608 }
2609 
2610 static int param_get_slot_table_size(char *buffer, struct kernel_param *kp)
2611 {
2612 	return param_get_uint(buffer, kp);
2613 }
2614 #define param_check_slot_table_size(name, p) \
2615 	__param_check(name, p, unsigned int);
2616 
2617 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
2618 		   slot_table_size, 0644);
2619 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
2620 		   slot_table_size, 0644);
2621 
2622