xref: /linux/net/sunrpc/xprtsock.c (revision 9d9659b6c0ebf7dde65ebada4c67980818245913)
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 				tcp_calldir;
215 
216 	u32			tcp_offset,
217 				tcp_reclen;
218 
219 	unsigned long		tcp_copied,
220 				tcp_flags;
221 
222 	/*
223 	 * Connection of transports
224 	 */
225 	struct delayed_work	connect_worker;
226 	struct sockaddr_storage	srcaddr;
227 	unsigned short		srcport;
228 
229 	/*
230 	 * UDP socket buffer size parameters
231 	 */
232 	size_t			rcvsize,
233 				sndsize;
234 
235 	/*
236 	 * Saved socket callback addresses
237 	 */
238 	void			(*old_data_ready)(struct sock *, int);
239 	void			(*old_state_change)(struct sock *);
240 	void			(*old_write_space)(struct sock *);
241 	void			(*old_error_report)(struct sock *);
242 };
243 
244 /*
245  * TCP receive state flags
246  */
247 #define TCP_RCV_LAST_FRAG	(1UL << 0)
248 #define TCP_RCV_COPY_FRAGHDR	(1UL << 1)
249 #define TCP_RCV_COPY_XID	(1UL << 2)
250 #define TCP_RCV_COPY_DATA	(1UL << 3)
251 #define TCP_RCV_READ_CALLDIR	(1UL << 4)
252 #define TCP_RCV_COPY_CALLDIR	(1UL << 5)
253 
254 /*
255  * TCP RPC flags
256  */
257 #define TCP_RPC_REPLY		(1UL << 6)
258 
259 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
260 {
261 	return (struct sockaddr *) &xprt->addr;
262 }
263 
264 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
265 {
266 	return (struct sockaddr_in *) &xprt->addr;
267 }
268 
269 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
270 {
271 	return (struct sockaddr_in6 *) &xprt->addr;
272 }
273 
274 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
275 {
276 	struct sockaddr *sap = xs_addr(xprt);
277 	struct sockaddr_in6 *sin6;
278 	struct sockaddr_in *sin;
279 	char buf[128];
280 
281 	(void)rpc_ntop(sap, buf, sizeof(buf));
282 	xprt->address_strings[RPC_DISPLAY_ADDR] = kstrdup(buf, GFP_KERNEL);
283 
284 	switch (sap->sa_family) {
285 	case AF_INET:
286 		sin = xs_addr_in(xprt);
287 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
288 		break;
289 	case AF_INET6:
290 		sin6 = xs_addr_in6(xprt);
291 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
292 		break;
293 	default:
294 		BUG();
295 	}
296 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
297 }
298 
299 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
300 {
301 	struct sockaddr *sap = xs_addr(xprt);
302 	char buf[128];
303 
304 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
305 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
306 
307 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
308 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
309 }
310 
311 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
312 				     const char *protocol,
313 				     const char *netid)
314 {
315 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
316 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
317 	xs_format_common_peer_addresses(xprt);
318 	xs_format_common_peer_ports(xprt);
319 }
320 
321 static void xs_update_peer_port(struct rpc_xprt *xprt)
322 {
323 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
324 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
325 
326 	xs_format_common_peer_ports(xprt);
327 }
328 
329 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
330 {
331 	unsigned int i;
332 
333 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
334 		switch (i) {
335 		case RPC_DISPLAY_PROTO:
336 		case RPC_DISPLAY_NETID:
337 			continue;
338 		default:
339 			kfree(xprt->address_strings[i]);
340 		}
341 }
342 
343 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
344 
345 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
346 {
347 	struct msghdr msg = {
348 		.msg_name	= addr,
349 		.msg_namelen	= addrlen,
350 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
351 	};
352 	struct kvec iov = {
353 		.iov_base	= vec->iov_base + base,
354 		.iov_len	= vec->iov_len - base,
355 	};
356 
357 	if (iov.iov_len != 0)
358 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
359 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
360 }
361 
362 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more)
363 {
364 	struct page **ppage;
365 	unsigned int remainder;
366 	int err, sent = 0;
367 
368 	remainder = xdr->page_len - base;
369 	base += xdr->page_base;
370 	ppage = xdr->pages + (base >> PAGE_SHIFT);
371 	base &= ~PAGE_MASK;
372 	for(;;) {
373 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
374 		int flags = XS_SENDMSG_FLAGS;
375 
376 		remainder -= len;
377 		if (remainder != 0 || more)
378 			flags |= MSG_MORE;
379 		err = sock->ops->sendpage(sock, *ppage, base, len, flags);
380 		if (remainder == 0 || err != len)
381 			break;
382 		sent += err;
383 		ppage++;
384 		base = 0;
385 	}
386 	if (sent == 0)
387 		return err;
388 	if (err > 0)
389 		sent += err;
390 	return sent;
391 }
392 
393 /**
394  * xs_sendpages - write pages directly to a socket
395  * @sock: socket to send on
396  * @addr: UDP only -- address of destination
397  * @addrlen: UDP only -- length of destination address
398  * @xdr: buffer containing this request
399  * @base: starting position in the buffer
400  *
401  */
402 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
403 {
404 	unsigned int remainder = xdr->len - base;
405 	int err, sent = 0;
406 
407 	if (unlikely(!sock))
408 		return -ENOTSOCK;
409 
410 	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
411 	if (base != 0) {
412 		addr = NULL;
413 		addrlen = 0;
414 	}
415 
416 	if (base < xdr->head[0].iov_len || addr != NULL) {
417 		unsigned int len = xdr->head[0].iov_len - base;
418 		remainder -= len;
419 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
420 		if (remainder == 0 || err != len)
421 			goto out;
422 		sent += err;
423 		base = 0;
424 	} else
425 		base -= xdr->head[0].iov_len;
426 
427 	if (base < xdr->page_len) {
428 		unsigned int len = xdr->page_len - base;
429 		remainder -= len;
430 		err = xs_send_pagedata(sock, xdr, base, remainder != 0);
431 		if (remainder == 0 || err != len)
432 			goto out;
433 		sent += err;
434 		base = 0;
435 	} else
436 		base -= xdr->page_len;
437 
438 	if (base >= xdr->tail[0].iov_len)
439 		return sent;
440 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
441 out:
442 	if (sent == 0)
443 		return err;
444 	if (err > 0)
445 		sent += err;
446 	return sent;
447 }
448 
449 static void xs_nospace_callback(struct rpc_task *task)
450 {
451 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
452 
453 	transport->inet->sk_write_pending--;
454 	clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
455 }
456 
457 /**
458  * xs_nospace - place task on wait queue if transmit was incomplete
459  * @task: task to put to sleep
460  *
461  */
462 static int xs_nospace(struct rpc_task *task)
463 {
464 	struct rpc_rqst *req = task->tk_rqstp;
465 	struct rpc_xprt *xprt = req->rq_xprt;
466 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
467 	int ret = 0;
468 
469 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
470 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
471 			req->rq_slen);
472 
473 	/* Protect against races with write_space */
474 	spin_lock_bh(&xprt->transport_lock);
475 
476 	/* Don't race with disconnect */
477 	if (xprt_connected(xprt)) {
478 		if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
479 			ret = -EAGAIN;
480 			/*
481 			 * Notify TCP that we're limited by the application
482 			 * window size
483 			 */
484 			set_bit(SOCK_NOSPACE, &transport->sock->flags);
485 			transport->inet->sk_write_pending++;
486 			/* ...and wait for more buffer space */
487 			xprt_wait_for_buffer_space(task, xs_nospace_callback);
488 		}
489 	} else {
490 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
491 		ret = -ENOTCONN;
492 	}
493 
494 	spin_unlock_bh(&xprt->transport_lock);
495 	return ret;
496 }
497 
498 /**
499  * xs_udp_send_request - write an RPC request to a UDP socket
500  * @task: address of RPC task that manages the state of an RPC request
501  *
502  * Return values:
503  *        0:	The request has been sent
504  *   EAGAIN:	The socket was blocked, please call again later to
505  *		complete the request
506  * ENOTCONN:	Caller needs to invoke connect logic then call again
507  *    other:	Some other error occured, the request was not sent
508  */
509 static int xs_udp_send_request(struct rpc_task *task)
510 {
511 	struct rpc_rqst *req = task->tk_rqstp;
512 	struct rpc_xprt *xprt = req->rq_xprt;
513 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
514 	struct xdr_buf *xdr = &req->rq_snd_buf;
515 	int status;
516 
517 	xs_pktdump("packet data:",
518 				req->rq_svec->iov_base,
519 				req->rq_svec->iov_len);
520 
521 	if (!xprt_bound(xprt))
522 		return -ENOTCONN;
523 	status = xs_sendpages(transport->sock,
524 			      xs_addr(xprt),
525 			      xprt->addrlen, xdr,
526 			      req->rq_bytes_sent);
527 
528 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
529 			xdr->len - req->rq_bytes_sent, status);
530 
531 	if (status >= 0) {
532 		req->rq_xmit_bytes_sent += status;
533 		if (status >= req->rq_slen)
534 			return 0;
535 		/* Still some bytes left; set up for a retry later. */
536 		status = -EAGAIN;
537 	}
538 
539 	switch (status) {
540 	case -ENOTSOCK:
541 		status = -ENOTCONN;
542 		/* Should we call xs_close() here? */
543 		break;
544 	case -EAGAIN:
545 		status = xs_nospace(task);
546 		break;
547 	default:
548 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
549 			-status);
550 	case -ENETUNREACH:
551 	case -EPIPE:
552 	case -ECONNREFUSED:
553 		/* When the server has died, an ICMP port unreachable message
554 		 * prompts ECONNREFUSED. */
555 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
556 	}
557 
558 	return status;
559 }
560 
561 /**
562  * xs_tcp_shutdown - gracefully shut down a TCP socket
563  * @xprt: transport
564  *
565  * Initiates a graceful shutdown of the TCP socket by calling the
566  * equivalent of shutdown(SHUT_WR);
567  */
568 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
569 {
570 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
571 	struct socket *sock = transport->sock;
572 
573 	if (sock != NULL)
574 		kernel_sock_shutdown(sock, SHUT_WR);
575 }
576 
577 static inline void xs_encode_tcp_record_marker(struct xdr_buf *buf)
578 {
579 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
580 	rpc_fraghdr *base = buf->head[0].iov_base;
581 	*base = htonl(RPC_LAST_STREAM_FRAGMENT | reclen);
582 }
583 
584 /**
585  * xs_tcp_send_request - write an RPC request to a TCP socket
586  * @task: address of RPC task that manages the state of an RPC request
587  *
588  * Return values:
589  *        0:	The request has been sent
590  *   EAGAIN:	The socket was blocked, please call again later to
591  *		complete the request
592  * ENOTCONN:	Caller needs to invoke connect logic then call again
593  *    other:	Some other error occured, the request was not sent
594  *
595  * XXX: In the case of soft timeouts, should we eventually give up
596  *	if sendmsg is not able to make progress?
597  */
598 static int xs_tcp_send_request(struct rpc_task *task)
599 {
600 	struct rpc_rqst *req = task->tk_rqstp;
601 	struct rpc_xprt *xprt = req->rq_xprt;
602 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
603 	struct xdr_buf *xdr = &req->rq_snd_buf;
604 	int status;
605 
606 	xs_encode_tcp_record_marker(&req->rq_snd_buf);
607 
608 	xs_pktdump("packet data:",
609 				req->rq_svec->iov_base,
610 				req->rq_svec->iov_len);
611 
612 	/* Continue transmitting the packet/record. We must be careful
613 	 * to cope with writespace callbacks arriving _after_ we have
614 	 * called sendmsg(). */
615 	while (1) {
616 		status = xs_sendpages(transport->sock,
617 					NULL, 0, xdr, req->rq_bytes_sent);
618 
619 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
620 				xdr->len - req->rq_bytes_sent, status);
621 
622 		if (unlikely(status < 0))
623 			break;
624 
625 		/* If we've sent the entire packet, immediately
626 		 * reset the count of bytes sent. */
627 		req->rq_bytes_sent += status;
628 		req->rq_xmit_bytes_sent += status;
629 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
630 			req->rq_bytes_sent = 0;
631 			return 0;
632 		}
633 
634 		if (status != 0)
635 			continue;
636 		status = -EAGAIN;
637 		break;
638 	}
639 
640 	switch (status) {
641 	case -ENOTSOCK:
642 		status = -ENOTCONN;
643 		/* Should we call xs_close() here? */
644 		break;
645 	case -EAGAIN:
646 		status = xs_nospace(task);
647 		break;
648 	default:
649 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
650 			-status);
651 	case -ECONNRESET:
652 	case -EPIPE:
653 		xs_tcp_shutdown(xprt);
654 	case -ECONNREFUSED:
655 	case -ENOTCONN:
656 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
657 	}
658 
659 	return status;
660 }
661 
662 /**
663  * xs_tcp_release_xprt - clean up after a tcp transmission
664  * @xprt: transport
665  * @task: rpc task
666  *
667  * This cleans up if an error causes us to abort the transmission of a request.
668  * In this case, the socket may need to be reset in order to avoid confusing
669  * the server.
670  */
671 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
672 {
673 	struct rpc_rqst *req;
674 
675 	if (task != xprt->snd_task)
676 		return;
677 	if (task == NULL)
678 		goto out_release;
679 	req = task->tk_rqstp;
680 	if (req->rq_bytes_sent == 0)
681 		goto out_release;
682 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
683 		goto out_release;
684 	set_bit(XPRT_CLOSE_WAIT, &task->tk_xprt->state);
685 out_release:
686 	xprt_release_xprt(xprt, task);
687 }
688 
689 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
690 {
691 	transport->old_data_ready = sk->sk_data_ready;
692 	transport->old_state_change = sk->sk_state_change;
693 	transport->old_write_space = sk->sk_write_space;
694 	transport->old_error_report = sk->sk_error_report;
695 }
696 
697 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
698 {
699 	sk->sk_data_ready = transport->old_data_ready;
700 	sk->sk_state_change = transport->old_state_change;
701 	sk->sk_write_space = transport->old_write_space;
702 	sk->sk_error_report = transport->old_error_report;
703 }
704 
705 static void xs_reset_transport(struct sock_xprt *transport)
706 {
707 	struct socket *sock = transport->sock;
708 	struct sock *sk = transport->inet;
709 
710 	if (sk == NULL)
711 		return;
712 
713 	write_lock_bh(&sk->sk_callback_lock);
714 	transport->inet = NULL;
715 	transport->sock = NULL;
716 
717 	sk->sk_user_data = NULL;
718 
719 	xs_restore_old_callbacks(transport, sk);
720 	write_unlock_bh(&sk->sk_callback_lock);
721 
722 	sk->sk_no_check = 0;
723 
724 	sock_release(sock);
725 }
726 
727 /**
728  * xs_close - close a socket
729  * @xprt: transport
730  *
731  * This is used when all requests are complete; ie, no DRC state remains
732  * on the server we want to save.
733  *
734  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
735  * xs_reset_transport() zeroing the socket from underneath a writer.
736  */
737 static void xs_close(struct rpc_xprt *xprt)
738 {
739 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
740 
741 	dprintk("RPC:       xs_close xprt %p\n", xprt);
742 
743 	xs_reset_transport(transport);
744 	xprt->reestablish_timeout = 0;
745 
746 	smp_mb__before_clear_bit();
747 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
748 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
749 	clear_bit(XPRT_CLOSING, &xprt->state);
750 	smp_mb__after_clear_bit();
751 	xprt_disconnect_done(xprt);
752 }
753 
754 static void xs_tcp_close(struct rpc_xprt *xprt)
755 {
756 	if (test_and_clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state))
757 		xs_close(xprt);
758 	else
759 		xs_tcp_shutdown(xprt);
760 }
761 
762 /**
763  * xs_destroy - prepare to shutdown a transport
764  * @xprt: doomed transport
765  *
766  */
767 static void xs_destroy(struct rpc_xprt *xprt)
768 {
769 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
770 
771 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
772 
773 	cancel_delayed_work_sync(&transport->connect_worker);
774 
775 	xs_close(xprt);
776 	xs_free_peer_addresses(xprt);
777 	xprt_free(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_bh(&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_bh(&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 	char *p;
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(transport->tcp_calldir) - offset;
940 	dprintk("RPC:       reading CALL/REPLY flag (%Zu bytes)\n", len);
941 	p = ((char *) &transport->tcp_calldir) + offset;
942 	used = xdr_skb_read_bits(desc, p, len);
943 	transport->tcp_offset += used;
944 	if (used != len)
945 		return;
946 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
947 	/*
948 	 * We don't yet have the XDR buffer, so we will write the calldir
949 	 * out after we get the buffer from the 'struct rpc_rqst'
950 	 */
951 	switch (ntohl(transport->tcp_calldir)) {
952 	case RPC_REPLY:
953 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
954 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
955 		transport->tcp_flags |= TCP_RPC_REPLY;
956 		break;
957 	case RPC_CALL:
958 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
959 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
960 		transport->tcp_flags &= ~TCP_RPC_REPLY;
961 		break;
962 	default:
963 		dprintk("RPC:       invalid request message type\n");
964 		xprt_force_disconnect(&transport->xprt);
965 	}
966 	xs_tcp_check_fraghdr(transport);
967 }
968 
969 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
970 				     struct xdr_skb_reader *desc,
971 				     struct rpc_rqst *req)
972 {
973 	struct sock_xprt *transport =
974 				container_of(xprt, struct sock_xprt, xprt);
975 	struct xdr_buf *rcvbuf;
976 	size_t len;
977 	ssize_t r;
978 
979 	rcvbuf = &req->rq_private_buf;
980 
981 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
982 		/*
983 		 * Save the RPC direction in the XDR buffer
984 		 */
985 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
986 			&transport->tcp_calldir,
987 			sizeof(transport->tcp_calldir));
988 		transport->tcp_copied += sizeof(transport->tcp_calldir);
989 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
990 	}
991 
992 	len = desc->count;
993 	if (len > transport->tcp_reclen - transport->tcp_offset) {
994 		struct xdr_skb_reader my_desc;
995 
996 		len = transport->tcp_reclen - transport->tcp_offset;
997 		memcpy(&my_desc, desc, sizeof(my_desc));
998 		my_desc.count = len;
999 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1000 					  &my_desc, xdr_skb_read_bits);
1001 		desc->count -= r;
1002 		desc->offset += r;
1003 	} else
1004 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1005 					  desc, xdr_skb_read_bits);
1006 
1007 	if (r > 0) {
1008 		transport->tcp_copied += r;
1009 		transport->tcp_offset += r;
1010 	}
1011 	if (r != len) {
1012 		/* Error when copying to the receive buffer,
1013 		 * usually because we weren't able to allocate
1014 		 * additional buffer pages. All we can do now
1015 		 * is turn off TCP_RCV_COPY_DATA, so the request
1016 		 * will not receive any additional updates,
1017 		 * and time out.
1018 		 * Any remaining data from this record will
1019 		 * be discarded.
1020 		 */
1021 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1022 		dprintk("RPC:       XID %08x truncated request\n",
1023 				ntohl(transport->tcp_xid));
1024 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1025 				"tcp_offset = %u, tcp_reclen = %u\n",
1026 				xprt, transport->tcp_copied,
1027 				transport->tcp_offset, transport->tcp_reclen);
1028 		return;
1029 	}
1030 
1031 	dprintk("RPC:       XID %08x read %Zd bytes\n",
1032 			ntohl(transport->tcp_xid), r);
1033 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1034 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1035 			transport->tcp_offset, transport->tcp_reclen);
1036 
1037 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1038 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1039 	else if (transport->tcp_offset == transport->tcp_reclen) {
1040 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1041 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1042 	}
1043 }
1044 
1045 /*
1046  * Finds the request corresponding to the RPC xid and invokes the common
1047  * tcp read code to read the data.
1048  */
1049 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1050 				    struct xdr_skb_reader *desc)
1051 {
1052 	struct sock_xprt *transport =
1053 				container_of(xprt, struct sock_xprt, xprt);
1054 	struct rpc_rqst *req;
1055 
1056 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1057 
1058 	/* Find and lock the request corresponding to this xid */
1059 	spin_lock(&xprt->transport_lock);
1060 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1061 	if (!req) {
1062 		dprintk("RPC:       XID %08x request not found!\n",
1063 				ntohl(transport->tcp_xid));
1064 		spin_unlock(&xprt->transport_lock);
1065 		return -1;
1066 	}
1067 
1068 	xs_tcp_read_common(xprt, desc, req);
1069 
1070 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1071 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1072 
1073 	spin_unlock(&xprt->transport_lock);
1074 	return 0;
1075 }
1076 
1077 #if defined(CONFIG_NFS_V4_1)
1078 /*
1079  * Obtains an rpc_rqst previously allocated and invokes the common
1080  * tcp read code to read the data.  The result is placed in the callback
1081  * queue.
1082  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1083  * connection and return -1.
1084  */
1085 static inline int xs_tcp_read_callback(struct rpc_xprt *xprt,
1086 				       struct xdr_skb_reader *desc)
1087 {
1088 	struct sock_xprt *transport =
1089 				container_of(xprt, struct sock_xprt, xprt);
1090 	struct rpc_rqst *req;
1091 
1092 	req = xprt_alloc_bc_request(xprt);
1093 	if (req == NULL) {
1094 		printk(KERN_WARNING "Callback slot table overflowed\n");
1095 		xprt_force_disconnect(xprt);
1096 		return -1;
1097 	}
1098 
1099 	req->rq_xid = transport->tcp_xid;
1100 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1101 	xs_tcp_read_common(xprt, desc, req);
1102 
1103 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) {
1104 		struct svc_serv *bc_serv = xprt->bc_serv;
1105 
1106 		/*
1107 		 * Add callback request to callback list.  The callback
1108 		 * service sleeps on the sv_cb_waitq waiting for new
1109 		 * requests.  Wake it up after adding enqueing the
1110 		 * request.
1111 		 */
1112 		dprintk("RPC:       add callback request to list\n");
1113 		spin_lock(&bc_serv->sv_cb_lock);
1114 		list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
1115 		spin_unlock(&bc_serv->sv_cb_lock);
1116 		wake_up(&bc_serv->sv_cb_waitq);
1117 	}
1118 
1119 	req->rq_private_buf.len = transport->tcp_copied;
1120 
1121 	return 0;
1122 }
1123 
1124 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1125 					struct xdr_skb_reader *desc)
1126 {
1127 	struct sock_xprt *transport =
1128 				container_of(xprt, struct sock_xprt, xprt);
1129 
1130 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1131 		xs_tcp_read_reply(xprt, desc) :
1132 		xs_tcp_read_callback(xprt, desc);
1133 }
1134 #else
1135 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1136 					struct xdr_skb_reader *desc)
1137 {
1138 	return xs_tcp_read_reply(xprt, desc);
1139 }
1140 #endif /* CONFIG_NFS_V4_1 */
1141 
1142 /*
1143  * Read data off the transport.  This can be either an RPC_CALL or an
1144  * RPC_REPLY.  Relay the processing to helper functions.
1145  */
1146 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1147 				    struct xdr_skb_reader *desc)
1148 {
1149 	struct sock_xprt *transport =
1150 				container_of(xprt, struct sock_xprt, xprt);
1151 
1152 	if (_xs_tcp_read_data(xprt, desc) == 0)
1153 		xs_tcp_check_fraghdr(transport);
1154 	else {
1155 		/*
1156 		 * The transport_lock protects the request handling.
1157 		 * There's no need to hold it to update the tcp_flags.
1158 		 */
1159 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1160 	}
1161 }
1162 
1163 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1164 {
1165 	size_t len;
1166 
1167 	len = transport->tcp_reclen - transport->tcp_offset;
1168 	if (len > desc->count)
1169 		len = desc->count;
1170 	desc->count -= len;
1171 	desc->offset += len;
1172 	transport->tcp_offset += len;
1173 	dprintk("RPC:       discarded %Zu bytes\n", len);
1174 	xs_tcp_check_fraghdr(transport);
1175 }
1176 
1177 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1178 {
1179 	struct rpc_xprt *xprt = rd_desc->arg.data;
1180 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1181 	struct xdr_skb_reader desc = {
1182 		.skb	= skb,
1183 		.offset	= offset,
1184 		.count	= len,
1185 	};
1186 
1187 	dprintk("RPC:       xs_tcp_data_recv started\n");
1188 	do {
1189 		/* Read in a new fragment marker if necessary */
1190 		/* Can we ever really expect to get completely empty fragments? */
1191 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1192 			xs_tcp_read_fraghdr(xprt, &desc);
1193 			continue;
1194 		}
1195 		/* Read in the xid if necessary */
1196 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1197 			xs_tcp_read_xid(transport, &desc);
1198 			continue;
1199 		}
1200 		/* Read in the call/reply flag */
1201 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1202 			xs_tcp_read_calldir(transport, &desc);
1203 			continue;
1204 		}
1205 		/* Read in the request data */
1206 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1207 			xs_tcp_read_data(xprt, &desc);
1208 			continue;
1209 		}
1210 		/* Skip over any trailing bytes on short reads */
1211 		xs_tcp_read_discard(transport, &desc);
1212 	} while (desc.count);
1213 	dprintk("RPC:       xs_tcp_data_recv done\n");
1214 	return len - desc.count;
1215 }
1216 
1217 /**
1218  * xs_tcp_data_ready - "data ready" callback for TCP sockets
1219  * @sk: socket with data to read
1220  * @bytes: how much data to read
1221  *
1222  */
1223 static void xs_tcp_data_ready(struct sock *sk, int bytes)
1224 {
1225 	struct rpc_xprt *xprt;
1226 	read_descriptor_t rd_desc;
1227 	int read;
1228 
1229 	dprintk("RPC:       xs_tcp_data_ready...\n");
1230 
1231 	read_lock_bh(&sk->sk_callback_lock);
1232 	if (!(xprt = xprt_from_sock(sk)))
1233 		goto out;
1234 	if (xprt->shutdown)
1235 		goto out;
1236 
1237 	/* Any data means we had a useful conversation, so
1238 	 * the we don't need to delay the next reconnect
1239 	 */
1240 	if (xprt->reestablish_timeout)
1241 		xprt->reestablish_timeout = 0;
1242 
1243 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1244 	rd_desc.arg.data = xprt;
1245 	do {
1246 		rd_desc.count = 65536;
1247 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1248 	} while (read > 0);
1249 out:
1250 	read_unlock_bh(&sk->sk_callback_lock);
1251 }
1252 
1253 /*
1254  * Do the equivalent of linger/linger2 handling for dealing with
1255  * broken servers that don't close the socket in a timely
1256  * fashion
1257  */
1258 static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt,
1259 		unsigned long timeout)
1260 {
1261 	struct sock_xprt *transport;
1262 
1263 	if (xprt_test_and_set_connecting(xprt))
1264 		return;
1265 	set_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1266 	transport = container_of(xprt, struct sock_xprt, xprt);
1267 	queue_delayed_work(rpciod_workqueue, &transport->connect_worker,
1268 			   timeout);
1269 }
1270 
1271 static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
1272 {
1273 	struct sock_xprt *transport;
1274 
1275 	transport = container_of(xprt, struct sock_xprt, xprt);
1276 
1277 	if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) ||
1278 	    !cancel_delayed_work(&transport->connect_worker))
1279 		return;
1280 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1281 	xprt_clear_connecting(xprt);
1282 }
1283 
1284 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
1285 {
1286 	smp_mb__before_clear_bit();
1287 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1288 	clear_bit(XPRT_CLOSING, &xprt->state);
1289 	smp_mb__after_clear_bit();
1290 	/* Mark transport as closed and wake up all pending tasks */
1291 	xprt_disconnect_done(xprt);
1292 }
1293 
1294 /**
1295  * xs_tcp_state_change - callback to handle TCP socket state changes
1296  * @sk: socket whose state has changed
1297  *
1298  */
1299 static void xs_tcp_state_change(struct sock *sk)
1300 {
1301 	struct rpc_xprt *xprt;
1302 
1303 	read_lock_bh(&sk->sk_callback_lock);
1304 	if (!(xprt = xprt_from_sock(sk)))
1305 		goto out;
1306 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1307 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1308 			sk->sk_state, xprt_connected(xprt),
1309 			sock_flag(sk, SOCK_DEAD),
1310 			sock_flag(sk, SOCK_ZAPPED),
1311 			sk->sk_shutdown);
1312 
1313 	switch (sk->sk_state) {
1314 	case TCP_ESTABLISHED:
1315 		spin_lock(&xprt->transport_lock);
1316 		if (!xprt_test_and_set_connected(xprt)) {
1317 			struct sock_xprt *transport = container_of(xprt,
1318 					struct sock_xprt, xprt);
1319 
1320 			/* Reset TCP record info */
1321 			transport->tcp_offset = 0;
1322 			transport->tcp_reclen = 0;
1323 			transport->tcp_copied = 0;
1324 			transport->tcp_flags =
1325 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1326 
1327 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1328 		}
1329 		spin_unlock(&xprt->transport_lock);
1330 		break;
1331 	case TCP_FIN_WAIT1:
1332 		/* The client initiated a shutdown of the socket */
1333 		xprt->connect_cookie++;
1334 		xprt->reestablish_timeout = 0;
1335 		set_bit(XPRT_CLOSING, &xprt->state);
1336 		smp_mb__before_clear_bit();
1337 		clear_bit(XPRT_CONNECTED, &xprt->state);
1338 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1339 		smp_mb__after_clear_bit();
1340 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1341 		break;
1342 	case TCP_CLOSE_WAIT:
1343 		/* The server initiated a shutdown of the socket */
1344 		xprt_force_disconnect(xprt);
1345 	case TCP_SYN_SENT:
1346 		xprt->connect_cookie++;
1347 	case TCP_CLOSING:
1348 		/*
1349 		 * If the server closed down the connection, make sure that
1350 		 * we back off before reconnecting
1351 		 */
1352 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1353 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1354 		break;
1355 	case TCP_LAST_ACK:
1356 		set_bit(XPRT_CLOSING, &xprt->state);
1357 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1358 		smp_mb__before_clear_bit();
1359 		clear_bit(XPRT_CONNECTED, &xprt->state);
1360 		smp_mb__after_clear_bit();
1361 		break;
1362 	case TCP_CLOSE:
1363 		xs_tcp_cancel_linger_timeout(xprt);
1364 		xs_sock_mark_closed(xprt);
1365 	}
1366  out:
1367 	read_unlock_bh(&sk->sk_callback_lock);
1368 }
1369 
1370 /**
1371  * xs_error_report - callback mainly for catching socket errors
1372  * @sk: socket
1373  */
1374 static void xs_error_report(struct sock *sk)
1375 {
1376 	struct rpc_xprt *xprt;
1377 
1378 	read_lock_bh(&sk->sk_callback_lock);
1379 	if (!(xprt = xprt_from_sock(sk)))
1380 		goto out;
1381 	dprintk("RPC:       %s client %p...\n"
1382 			"RPC:       error %d\n",
1383 			__func__, xprt, sk->sk_err);
1384 	xprt_wake_pending_tasks(xprt, -EAGAIN);
1385 out:
1386 	read_unlock_bh(&sk->sk_callback_lock);
1387 }
1388 
1389 static void xs_write_space(struct sock *sk)
1390 {
1391 	struct socket *sock;
1392 	struct rpc_xprt *xprt;
1393 
1394 	if (unlikely(!(sock = sk->sk_socket)))
1395 		return;
1396 	clear_bit(SOCK_NOSPACE, &sock->flags);
1397 
1398 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1399 		return;
1400 	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
1401 		return;
1402 
1403 	xprt_write_space(xprt);
1404 }
1405 
1406 /**
1407  * xs_udp_write_space - callback invoked when socket buffer space
1408  *                             becomes available
1409  * @sk: socket whose state has changed
1410  *
1411  * Called when more output buffer space is available for this socket.
1412  * We try not to wake our writers until they can make "significant"
1413  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1414  * with a bunch of small requests.
1415  */
1416 static void xs_udp_write_space(struct sock *sk)
1417 {
1418 	read_lock_bh(&sk->sk_callback_lock);
1419 
1420 	/* from net/core/sock.c:sock_def_write_space */
1421 	if (sock_writeable(sk))
1422 		xs_write_space(sk);
1423 
1424 	read_unlock_bh(&sk->sk_callback_lock);
1425 }
1426 
1427 /**
1428  * xs_tcp_write_space - callback invoked when socket buffer space
1429  *                             becomes available
1430  * @sk: socket whose state has changed
1431  *
1432  * Called when more output buffer space is available for this socket.
1433  * We try not to wake our writers until they can make "significant"
1434  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1435  * with a bunch of small requests.
1436  */
1437 static void xs_tcp_write_space(struct sock *sk)
1438 {
1439 	read_lock_bh(&sk->sk_callback_lock);
1440 
1441 	/* from net/core/stream.c:sk_stream_write_space */
1442 	if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
1443 		xs_write_space(sk);
1444 
1445 	read_unlock_bh(&sk->sk_callback_lock);
1446 }
1447 
1448 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1449 {
1450 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1451 	struct sock *sk = transport->inet;
1452 
1453 	if (transport->rcvsize) {
1454 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1455 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1456 	}
1457 	if (transport->sndsize) {
1458 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1459 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1460 		sk->sk_write_space(sk);
1461 	}
1462 }
1463 
1464 /**
1465  * xs_udp_set_buffer_size - set send and receive limits
1466  * @xprt: generic transport
1467  * @sndsize: requested size of send buffer, in bytes
1468  * @rcvsize: requested size of receive buffer, in bytes
1469  *
1470  * Set socket send and receive buffer size limits.
1471  */
1472 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1473 {
1474 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1475 
1476 	transport->sndsize = 0;
1477 	if (sndsize)
1478 		transport->sndsize = sndsize + 1024;
1479 	transport->rcvsize = 0;
1480 	if (rcvsize)
1481 		transport->rcvsize = rcvsize + 1024;
1482 
1483 	xs_udp_do_set_buffer_size(xprt);
1484 }
1485 
1486 /**
1487  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1488  * @task: task that timed out
1489  *
1490  * Adjust the congestion window after a retransmit timeout has occurred.
1491  */
1492 static void xs_udp_timer(struct rpc_task *task)
1493 {
1494 	xprt_adjust_cwnd(task, -ETIMEDOUT);
1495 }
1496 
1497 static unsigned short xs_get_random_port(void)
1498 {
1499 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1500 	unsigned short rand = (unsigned short) net_random() % range;
1501 	return rand + xprt_min_resvport;
1502 }
1503 
1504 /**
1505  * xs_set_port - reset the port number in the remote endpoint address
1506  * @xprt: generic transport
1507  * @port: new port number
1508  *
1509  */
1510 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1511 {
1512 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1513 
1514 	rpc_set_port(xs_addr(xprt), port);
1515 	xs_update_peer_port(xprt);
1516 }
1517 
1518 static unsigned short xs_get_srcport(struct sock_xprt *transport)
1519 {
1520 	unsigned short port = transport->srcport;
1521 
1522 	if (port == 0 && transport->xprt.resvport)
1523 		port = xs_get_random_port();
1524 	return port;
1525 }
1526 
1527 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1528 {
1529 	if (transport->srcport != 0)
1530 		transport->srcport = 0;
1531 	if (!transport->xprt.resvport)
1532 		return 0;
1533 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1534 		return xprt_max_resvport;
1535 	return --port;
1536 }
1537 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1538 {
1539 	struct sockaddr_storage myaddr;
1540 	int err, nloop = 0;
1541 	unsigned short port = xs_get_srcport(transport);
1542 	unsigned short last;
1543 
1544 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1545 	do {
1546 		rpc_set_port((struct sockaddr *)&myaddr, port);
1547 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1548 				transport->xprt.addrlen);
1549 		if (port == 0)
1550 			break;
1551 		if (err == 0) {
1552 			transport->srcport = port;
1553 			break;
1554 		}
1555 		last = port;
1556 		port = xs_next_srcport(transport, port);
1557 		if (port > last)
1558 			nloop++;
1559 	} while (err == -EADDRINUSE && nloop != 2);
1560 
1561 	if (myaddr.ss_family == AF_INET)
1562 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1563 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1564 				port, err ? "failed" : "ok", err);
1565 	else
1566 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1567 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1568 				port, err ? "failed" : "ok", err);
1569 	return err;
1570 }
1571 
1572 
1573 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1574 static struct lock_class_key xs_key[2];
1575 static struct lock_class_key xs_slock_key[2];
1576 
1577 static inline void xs_reclassify_socket4(struct socket *sock)
1578 {
1579 	struct sock *sk = sock->sk;
1580 
1581 	BUG_ON(sock_owned_by_user(sk));
1582 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1583 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1584 }
1585 
1586 static inline void xs_reclassify_socket6(struct socket *sock)
1587 {
1588 	struct sock *sk = sock->sk;
1589 
1590 	BUG_ON(sock_owned_by_user(sk));
1591 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1592 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1593 }
1594 
1595 static inline void xs_reclassify_socket(int family, struct socket *sock)
1596 {
1597 	switch (family) {
1598 	case AF_INET:
1599 		xs_reclassify_socket4(sock);
1600 		break;
1601 	case AF_INET6:
1602 		xs_reclassify_socket6(sock);
1603 		break;
1604 	}
1605 }
1606 #else
1607 static inline void xs_reclassify_socket4(struct socket *sock)
1608 {
1609 }
1610 
1611 static inline void xs_reclassify_socket6(struct socket *sock)
1612 {
1613 }
1614 
1615 static inline void xs_reclassify_socket(int family, struct socket *sock)
1616 {
1617 }
1618 #endif
1619 
1620 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1621 		struct sock_xprt *transport, int family, int type, int protocol)
1622 {
1623 	struct socket *sock;
1624 	int err;
1625 
1626 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1627 	if (err < 0) {
1628 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1629 				protocol, -err);
1630 		goto out;
1631 	}
1632 	xs_reclassify_socket(family, sock);
1633 
1634 	err = xs_bind(transport, sock);
1635 	if (err) {
1636 		sock_release(sock);
1637 		goto out;
1638 	}
1639 
1640 	return sock;
1641 out:
1642 	return ERR_PTR(err);
1643 }
1644 
1645 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1646 {
1647 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1648 
1649 	if (!transport->inet) {
1650 		struct sock *sk = sock->sk;
1651 
1652 		write_lock_bh(&sk->sk_callback_lock);
1653 
1654 		xs_save_old_callbacks(transport, sk);
1655 
1656 		sk->sk_user_data = xprt;
1657 		sk->sk_data_ready = xs_udp_data_ready;
1658 		sk->sk_write_space = xs_udp_write_space;
1659 		sk->sk_error_report = xs_error_report;
1660 		sk->sk_no_check = UDP_CSUM_NORCV;
1661 		sk->sk_allocation = GFP_ATOMIC;
1662 
1663 		xprt_set_connected(xprt);
1664 
1665 		/* Reset to new socket */
1666 		transport->sock = sock;
1667 		transport->inet = sk;
1668 
1669 		write_unlock_bh(&sk->sk_callback_lock);
1670 	}
1671 	xs_udp_do_set_buffer_size(xprt);
1672 }
1673 
1674 static void xs_udp_setup_socket(struct work_struct *work)
1675 {
1676 	struct sock_xprt *transport =
1677 		container_of(work, struct sock_xprt, connect_worker.work);
1678 	struct rpc_xprt *xprt = &transport->xprt;
1679 	struct socket *sock = transport->sock;
1680 	int status = -EIO;
1681 
1682 	if (xprt->shutdown)
1683 		goto out;
1684 
1685 	/* Start by resetting any existing state */
1686 	xs_reset_transport(transport);
1687 	sock = xs_create_sock(xprt, transport,
1688 			xs_addr(xprt)->sa_family, SOCK_DGRAM, IPPROTO_UDP);
1689 	if (IS_ERR(sock))
1690 		goto out;
1691 
1692 	dprintk("RPC:       worker connecting xprt %p via %s to "
1693 				"%s (port %s)\n", xprt,
1694 			xprt->address_strings[RPC_DISPLAY_PROTO],
1695 			xprt->address_strings[RPC_DISPLAY_ADDR],
1696 			xprt->address_strings[RPC_DISPLAY_PORT]);
1697 
1698 	xs_udp_finish_connecting(xprt, sock);
1699 	status = 0;
1700 out:
1701 	xprt_clear_connecting(xprt);
1702 	xprt_wake_pending_tasks(xprt, status);
1703 }
1704 
1705 /*
1706  * We need to preserve the port number so the reply cache on the server can
1707  * find our cached RPC replies when we get around to reconnecting.
1708  */
1709 static void xs_abort_connection(struct sock_xprt *transport)
1710 {
1711 	int result;
1712 	struct sockaddr any;
1713 
1714 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", transport);
1715 
1716 	/*
1717 	 * Disconnect the transport socket by doing a connect operation
1718 	 * with AF_UNSPEC.  This should return immediately...
1719 	 */
1720 	memset(&any, 0, sizeof(any));
1721 	any.sa_family = AF_UNSPEC;
1722 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
1723 	if (!result)
1724 		xs_sock_mark_closed(&transport->xprt);
1725 	else
1726 		dprintk("RPC:       AF_UNSPEC connect return code %d\n",
1727 				result);
1728 }
1729 
1730 static void xs_tcp_reuse_connection(struct sock_xprt *transport)
1731 {
1732 	unsigned int state = transport->inet->sk_state;
1733 
1734 	if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED) {
1735 		/* we don't need to abort the connection if the socket
1736 		 * hasn't undergone a shutdown
1737 		 */
1738 		if (transport->inet->sk_shutdown == 0)
1739 			return;
1740 		dprintk("RPC:       %s: TCP_CLOSEd and sk_shutdown set to %d\n",
1741 				__func__, transport->inet->sk_shutdown);
1742 	}
1743 	if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT)) {
1744 		/* we don't need to abort the connection if the socket
1745 		 * hasn't undergone a shutdown
1746 		 */
1747 		if (transport->inet->sk_shutdown == 0)
1748 			return;
1749 		dprintk("RPC:       %s: ESTABLISHED/SYN_SENT "
1750 				"sk_shutdown set to %d\n",
1751 				__func__, transport->inet->sk_shutdown);
1752 	}
1753 	xs_abort_connection(transport);
1754 }
1755 
1756 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1757 {
1758 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1759 
1760 	if (!transport->inet) {
1761 		struct sock *sk = sock->sk;
1762 
1763 		write_lock_bh(&sk->sk_callback_lock);
1764 
1765 		xs_save_old_callbacks(transport, sk);
1766 
1767 		sk->sk_user_data = xprt;
1768 		sk->sk_data_ready = xs_tcp_data_ready;
1769 		sk->sk_state_change = xs_tcp_state_change;
1770 		sk->sk_write_space = xs_tcp_write_space;
1771 		sk->sk_error_report = xs_error_report;
1772 		sk->sk_allocation = GFP_ATOMIC;
1773 
1774 		/* socket options */
1775 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
1776 		sock_reset_flag(sk, SOCK_LINGER);
1777 		tcp_sk(sk)->linger2 = 0;
1778 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
1779 
1780 		xprt_clear_connected(xprt);
1781 
1782 		/* Reset to new socket */
1783 		transport->sock = sock;
1784 		transport->inet = sk;
1785 
1786 		write_unlock_bh(&sk->sk_callback_lock);
1787 	}
1788 
1789 	if (!xprt_bound(xprt))
1790 		return -ENOTCONN;
1791 
1792 	/* Tell the socket layer to start connecting... */
1793 	xprt->stat.connect_count++;
1794 	xprt->stat.connect_start = jiffies;
1795 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
1796 }
1797 
1798 /**
1799  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
1800  * @xprt: RPC transport to connect
1801  * @transport: socket transport to connect
1802  * @create_sock: function to create a socket of the correct type
1803  *
1804  * Invoked by a work queue tasklet.
1805  */
1806 static void xs_tcp_setup_socket(struct work_struct *work)
1807 {
1808 	struct sock_xprt *transport =
1809 		container_of(work, struct sock_xprt, connect_worker.work);
1810 	struct socket *sock = transport->sock;
1811 	struct rpc_xprt *xprt = &transport->xprt;
1812 	int status = -EIO;
1813 
1814 	if (xprt->shutdown)
1815 		goto out;
1816 
1817 	if (!sock) {
1818 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1819 		sock = xs_create_sock(xprt, transport,
1820 				xs_addr(xprt)->sa_family, SOCK_STREAM, IPPROTO_TCP);
1821 		if (IS_ERR(sock)) {
1822 			status = PTR_ERR(sock);
1823 			goto out;
1824 		}
1825 	} else {
1826 		int abort_and_exit;
1827 
1828 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
1829 				&xprt->state);
1830 		/* "close" the socket, preserving the local port */
1831 		xs_tcp_reuse_connection(transport);
1832 
1833 		if (abort_and_exit)
1834 			goto out_eagain;
1835 	}
1836 
1837 	dprintk("RPC:       worker connecting xprt %p via %s to "
1838 				"%s (port %s)\n", xprt,
1839 			xprt->address_strings[RPC_DISPLAY_PROTO],
1840 			xprt->address_strings[RPC_DISPLAY_ADDR],
1841 			xprt->address_strings[RPC_DISPLAY_PORT]);
1842 
1843 	status = xs_tcp_finish_connecting(xprt, sock);
1844 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
1845 			xprt, -status, xprt_connected(xprt),
1846 			sock->sk->sk_state);
1847 	switch (status) {
1848 	default:
1849 		printk("%s: connect returned unhandled error %d\n",
1850 			__func__, status);
1851 	case -EADDRNOTAVAIL:
1852 		/* We're probably in TIME_WAIT. Get rid of existing socket,
1853 		 * and retry
1854 		 */
1855 		set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1856 		xprt_force_disconnect(xprt);
1857 		break;
1858 	case -ECONNREFUSED:
1859 	case -ECONNRESET:
1860 	case -ENETUNREACH:
1861 		/* retry with existing socket, after a delay */
1862 	case 0:
1863 	case -EINPROGRESS:
1864 	case -EALREADY:
1865 		xprt_clear_connecting(xprt);
1866 		return;
1867 	case -EINVAL:
1868 		/* Happens, for instance, if the user specified a link
1869 		 * local IPv6 address without a scope-id.
1870 		 */
1871 		goto out;
1872 	}
1873 out_eagain:
1874 	status = -EAGAIN;
1875 out:
1876 	xprt_clear_connecting(xprt);
1877 	xprt_wake_pending_tasks(xprt, status);
1878 }
1879 
1880 /**
1881  * xs_connect - connect a socket to a remote endpoint
1882  * @task: address of RPC task that manages state of connect request
1883  *
1884  * TCP: If the remote end dropped the connection, delay reconnecting.
1885  *
1886  * UDP socket connects are synchronous, but we use a work queue anyway
1887  * to guarantee that even unprivileged user processes can set up a
1888  * socket on a privileged port.
1889  *
1890  * If a UDP socket connect fails, the delay behavior here prevents
1891  * retry floods (hard mounts).
1892  */
1893 static void xs_connect(struct rpc_task *task)
1894 {
1895 	struct rpc_xprt *xprt = task->tk_xprt;
1896 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1897 
1898 	if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) {
1899 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
1900 				"seconds\n",
1901 				xprt, xprt->reestablish_timeout / HZ);
1902 		queue_delayed_work(rpciod_workqueue,
1903 				   &transport->connect_worker,
1904 				   xprt->reestablish_timeout);
1905 		xprt->reestablish_timeout <<= 1;
1906 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1907 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1908 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
1909 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
1910 	} else {
1911 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
1912 		queue_delayed_work(rpciod_workqueue,
1913 				   &transport->connect_worker, 0);
1914 	}
1915 }
1916 
1917 /**
1918  * xs_udp_print_stats - display UDP socket-specifc stats
1919  * @xprt: rpc_xprt struct containing statistics
1920  * @seq: output file
1921  *
1922  */
1923 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
1924 {
1925 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1926 
1927 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %Lu %Lu\n",
1928 			transport->srcport,
1929 			xprt->stat.bind_count,
1930 			xprt->stat.sends,
1931 			xprt->stat.recvs,
1932 			xprt->stat.bad_xids,
1933 			xprt->stat.req_u,
1934 			xprt->stat.bklog_u);
1935 }
1936 
1937 /**
1938  * xs_tcp_print_stats - display TCP socket-specifc stats
1939  * @xprt: rpc_xprt struct containing statistics
1940  * @seq: output file
1941  *
1942  */
1943 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
1944 {
1945 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1946 	long idle_time = 0;
1947 
1948 	if (xprt_connected(xprt))
1949 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
1950 
1951 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu %Lu %Lu\n",
1952 			transport->srcport,
1953 			xprt->stat.bind_count,
1954 			xprt->stat.connect_count,
1955 			xprt->stat.connect_time,
1956 			idle_time,
1957 			xprt->stat.sends,
1958 			xprt->stat.recvs,
1959 			xprt->stat.bad_xids,
1960 			xprt->stat.req_u,
1961 			xprt->stat.bklog_u);
1962 }
1963 
1964 /*
1965  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
1966  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
1967  * to use the server side send routines.
1968  */
1969 static void *bc_malloc(struct rpc_task *task, size_t size)
1970 {
1971 	struct page *page;
1972 	struct rpc_buffer *buf;
1973 
1974 	BUG_ON(size > PAGE_SIZE - sizeof(struct rpc_buffer));
1975 	page = alloc_page(GFP_KERNEL);
1976 
1977 	if (!page)
1978 		return NULL;
1979 
1980 	buf = page_address(page);
1981 	buf->len = PAGE_SIZE;
1982 
1983 	return buf->data;
1984 }
1985 
1986 /*
1987  * Free the space allocated in the bc_alloc routine
1988  */
1989 static void bc_free(void *buffer)
1990 {
1991 	struct rpc_buffer *buf;
1992 
1993 	if (!buffer)
1994 		return;
1995 
1996 	buf = container_of(buffer, struct rpc_buffer, data);
1997 	free_page((unsigned long)buf);
1998 }
1999 
2000 /*
2001  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2002  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2003  */
2004 static int bc_sendto(struct rpc_rqst *req)
2005 {
2006 	int len;
2007 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2008 	struct rpc_xprt *xprt = req->rq_xprt;
2009 	struct sock_xprt *transport =
2010 				container_of(xprt, struct sock_xprt, xprt);
2011 	struct socket *sock = transport->sock;
2012 	unsigned long headoff;
2013 	unsigned long tailoff;
2014 
2015 	/*
2016 	 * Set up the rpc header and record marker stuff
2017 	 */
2018 	xs_encode_tcp_record_marker(xbufp);
2019 
2020 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2021 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2022 	len = svc_send_common(sock, xbufp,
2023 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2024 			      xbufp->tail[0].iov_base, tailoff);
2025 
2026 	if (len != xbufp->len) {
2027 		printk(KERN_NOTICE "Error sending entire callback!\n");
2028 		len = -EAGAIN;
2029 	}
2030 
2031 	return len;
2032 }
2033 
2034 /*
2035  * The send routine. Borrows from svc_send
2036  */
2037 static int bc_send_request(struct rpc_task *task)
2038 {
2039 	struct rpc_rqst *req = task->tk_rqstp;
2040 	struct svc_xprt	*xprt;
2041 	struct svc_sock         *svsk;
2042 	u32                     len;
2043 
2044 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2045 	/*
2046 	 * Get the server socket associated with this callback xprt
2047 	 */
2048 	xprt = req->rq_xprt->bc_xprt;
2049 	svsk = container_of(xprt, struct svc_sock, sk_xprt);
2050 
2051 	/*
2052 	 * Grab the mutex to serialize data as the connection is shared
2053 	 * with the fore channel
2054 	 */
2055 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2056 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2057 		if (!mutex_trylock(&xprt->xpt_mutex))
2058 			return -EAGAIN;
2059 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2060 	}
2061 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2062 		len = -ENOTCONN;
2063 	else
2064 		len = bc_sendto(req);
2065 	mutex_unlock(&xprt->xpt_mutex);
2066 
2067 	if (len > 0)
2068 		len = 0;
2069 
2070 	return len;
2071 }
2072 
2073 /*
2074  * The close routine. Since this is client initiated, we do nothing
2075  */
2076 
2077 static void bc_close(struct rpc_xprt *xprt)
2078 {
2079 }
2080 
2081 /*
2082  * The xprt destroy routine. Again, because this connection is client
2083  * initiated, we do nothing
2084  */
2085 
2086 static void bc_destroy(struct rpc_xprt *xprt)
2087 {
2088 }
2089 
2090 static struct rpc_xprt_ops xs_udp_ops = {
2091 	.set_buffer_size	= xs_udp_set_buffer_size,
2092 	.reserve_xprt		= xprt_reserve_xprt_cong,
2093 	.release_xprt		= xprt_release_xprt_cong,
2094 	.rpcbind		= rpcb_getport_async,
2095 	.set_port		= xs_set_port,
2096 	.connect		= xs_connect,
2097 	.buf_alloc		= rpc_malloc,
2098 	.buf_free		= rpc_free,
2099 	.send_request		= xs_udp_send_request,
2100 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2101 	.timer			= xs_udp_timer,
2102 	.release_request	= xprt_release_rqst_cong,
2103 	.close			= xs_close,
2104 	.destroy		= xs_destroy,
2105 	.print_stats		= xs_udp_print_stats,
2106 };
2107 
2108 static struct rpc_xprt_ops xs_tcp_ops = {
2109 	.reserve_xprt		= xprt_reserve_xprt,
2110 	.release_xprt		= xs_tcp_release_xprt,
2111 	.rpcbind		= rpcb_getport_async,
2112 	.set_port		= xs_set_port,
2113 	.connect		= xs_connect,
2114 	.buf_alloc		= rpc_malloc,
2115 	.buf_free		= rpc_free,
2116 	.send_request		= xs_tcp_send_request,
2117 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2118 	.close			= xs_tcp_close,
2119 	.destroy		= xs_destroy,
2120 	.print_stats		= xs_tcp_print_stats,
2121 };
2122 
2123 /*
2124  * The rpc_xprt_ops for the server backchannel
2125  */
2126 
2127 static struct rpc_xprt_ops bc_tcp_ops = {
2128 	.reserve_xprt		= xprt_reserve_xprt,
2129 	.release_xprt		= xprt_release_xprt,
2130 	.buf_alloc		= bc_malloc,
2131 	.buf_free		= bc_free,
2132 	.send_request		= bc_send_request,
2133 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2134 	.close			= bc_close,
2135 	.destroy		= bc_destroy,
2136 	.print_stats		= xs_tcp_print_stats,
2137 };
2138 
2139 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2140 {
2141 	static const struct sockaddr_in sin = {
2142 		.sin_family		= AF_INET,
2143 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2144 	};
2145 	static const struct sockaddr_in6 sin6 = {
2146 		.sin6_family		= AF_INET6,
2147 		.sin6_addr		= IN6ADDR_ANY_INIT,
2148 	};
2149 
2150 	switch (family) {
2151 	case AF_INET:
2152 		memcpy(sap, &sin, sizeof(sin));
2153 		break;
2154 	case AF_INET6:
2155 		memcpy(sap, &sin6, sizeof(sin6));
2156 		break;
2157 	default:
2158 		dprintk("RPC:       %s: Bad address family\n", __func__);
2159 		return -EAFNOSUPPORT;
2160 	}
2161 	return 0;
2162 }
2163 
2164 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2165 				      unsigned int slot_table_size)
2166 {
2167 	struct rpc_xprt *xprt;
2168 	struct sock_xprt *new;
2169 
2170 	if (args->addrlen > sizeof(xprt->addr)) {
2171 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2172 		return ERR_PTR(-EBADF);
2173 	}
2174 
2175 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size);
2176 	if (xprt == NULL) {
2177 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2178 				"rpc_xprt\n");
2179 		return ERR_PTR(-ENOMEM);
2180 	}
2181 
2182 	new = container_of(xprt, struct sock_xprt, xprt);
2183 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2184 	xprt->addrlen = args->addrlen;
2185 	if (args->srcaddr)
2186 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2187 	else {
2188 		int err;
2189 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2190 					(struct sockaddr *)&new->srcaddr);
2191 		if (err != 0)
2192 			return ERR_PTR(err);
2193 	}
2194 
2195 	return xprt;
2196 }
2197 
2198 static const struct rpc_timeout xs_udp_default_timeout = {
2199 	.to_initval = 5 * HZ,
2200 	.to_maxval = 30 * HZ,
2201 	.to_increment = 5 * HZ,
2202 	.to_retries = 5,
2203 };
2204 
2205 /**
2206  * xs_setup_udp - Set up transport to use a UDP socket
2207  * @args: rpc transport creation arguments
2208  *
2209  */
2210 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2211 {
2212 	struct sockaddr *addr = args->dstaddr;
2213 	struct rpc_xprt *xprt;
2214 	struct sock_xprt *transport;
2215 	struct rpc_xprt *ret;
2216 
2217 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries);
2218 	if (IS_ERR(xprt))
2219 		return xprt;
2220 	transport = container_of(xprt, struct sock_xprt, xprt);
2221 
2222 	xprt->prot = IPPROTO_UDP;
2223 	xprt->tsh_size = 0;
2224 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2225 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2226 
2227 	xprt->bind_timeout = XS_BIND_TO;
2228 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2229 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2230 
2231 	xprt->ops = &xs_udp_ops;
2232 
2233 	xprt->timeout = &xs_udp_default_timeout;
2234 
2235 	switch (addr->sa_family) {
2236 	case AF_INET:
2237 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2238 			xprt_set_bound(xprt);
2239 
2240 		INIT_DELAYED_WORK(&transport->connect_worker,
2241 					xs_udp_setup_socket);
2242 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2243 		break;
2244 	case AF_INET6:
2245 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2246 			xprt_set_bound(xprt);
2247 
2248 		INIT_DELAYED_WORK(&transport->connect_worker,
2249 					xs_udp_setup_socket);
2250 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2251 		break;
2252 	default:
2253 		ret = ERR_PTR(-EAFNOSUPPORT);
2254 		goto out_err;
2255 	}
2256 
2257 	if (xprt_bound(xprt))
2258 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2259 				xprt->address_strings[RPC_DISPLAY_ADDR],
2260 				xprt->address_strings[RPC_DISPLAY_PORT],
2261 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2262 	else
2263 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2264 				xprt->address_strings[RPC_DISPLAY_ADDR],
2265 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2266 
2267 	if (try_module_get(THIS_MODULE))
2268 		return xprt;
2269 	ret = ERR_PTR(-EINVAL);
2270 out_err:
2271 	xprt_free(xprt);
2272 	return ret;
2273 }
2274 
2275 static const struct rpc_timeout xs_tcp_default_timeout = {
2276 	.to_initval = 60 * HZ,
2277 	.to_maxval = 60 * HZ,
2278 	.to_retries = 2,
2279 };
2280 
2281 /**
2282  * xs_setup_tcp - Set up transport to use a TCP socket
2283  * @args: rpc transport creation arguments
2284  *
2285  */
2286 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2287 {
2288 	struct sockaddr *addr = args->dstaddr;
2289 	struct rpc_xprt *xprt;
2290 	struct sock_xprt *transport;
2291 	struct rpc_xprt *ret;
2292 
2293 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
2294 	if (IS_ERR(xprt))
2295 		return xprt;
2296 	transport = container_of(xprt, struct sock_xprt, xprt);
2297 
2298 	xprt->prot = IPPROTO_TCP;
2299 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2300 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2301 
2302 	xprt->bind_timeout = XS_BIND_TO;
2303 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2304 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2305 
2306 	xprt->ops = &xs_tcp_ops;
2307 	xprt->timeout = &xs_tcp_default_timeout;
2308 
2309 	switch (addr->sa_family) {
2310 	case AF_INET:
2311 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2312 			xprt_set_bound(xprt);
2313 
2314 		INIT_DELAYED_WORK(&transport->connect_worker,
2315 					xs_tcp_setup_socket);
2316 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
2317 		break;
2318 	case AF_INET6:
2319 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2320 			xprt_set_bound(xprt);
2321 
2322 		INIT_DELAYED_WORK(&transport->connect_worker,
2323 					xs_tcp_setup_socket);
2324 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
2325 		break;
2326 	default:
2327 		ret = ERR_PTR(-EAFNOSUPPORT);
2328 		goto out_err;
2329 	}
2330 
2331 	if (xprt_bound(xprt))
2332 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2333 				xprt->address_strings[RPC_DISPLAY_ADDR],
2334 				xprt->address_strings[RPC_DISPLAY_PORT],
2335 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2336 	else
2337 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2338 				xprt->address_strings[RPC_DISPLAY_ADDR],
2339 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2340 
2341 
2342 	if (try_module_get(THIS_MODULE))
2343 		return xprt;
2344 	ret = ERR_PTR(-EINVAL);
2345 out_err:
2346 	xprt_free(xprt);
2347 	return ret;
2348 }
2349 
2350 /**
2351  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
2352  * @args: rpc transport creation arguments
2353  *
2354  */
2355 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
2356 {
2357 	struct sockaddr *addr = args->dstaddr;
2358 	struct rpc_xprt *xprt;
2359 	struct sock_xprt *transport;
2360 	struct svc_sock *bc_sock;
2361 	struct rpc_xprt *ret;
2362 
2363 	if (args->bc_xprt->xpt_bc_xprt) {
2364 		/*
2365 		 * This server connection already has a backchannel
2366 		 * export; we can't create a new one, as we wouldn't be
2367 		 * able to match replies based on xid any more.  So,
2368 		 * reuse the already-existing one:
2369 		 */
2370 		 return args->bc_xprt->xpt_bc_xprt;
2371 	}
2372 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
2373 	if (IS_ERR(xprt))
2374 		return xprt;
2375 	transport = container_of(xprt, struct sock_xprt, xprt);
2376 
2377 	xprt->prot = IPPROTO_TCP;
2378 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2379 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2380 	xprt->timeout = &xs_tcp_default_timeout;
2381 
2382 	/* backchannel */
2383 	xprt_set_bound(xprt);
2384 	xprt->bind_timeout = 0;
2385 	xprt->reestablish_timeout = 0;
2386 	xprt->idle_timeout = 0;
2387 
2388 	xprt->ops = &bc_tcp_ops;
2389 
2390 	switch (addr->sa_family) {
2391 	case AF_INET:
2392 		xs_format_peer_addresses(xprt, "tcp",
2393 					 RPCBIND_NETID_TCP);
2394 		break;
2395 	case AF_INET6:
2396 		xs_format_peer_addresses(xprt, "tcp",
2397 				   RPCBIND_NETID_TCP6);
2398 		break;
2399 	default:
2400 		ret = ERR_PTR(-EAFNOSUPPORT);
2401 		goto out_err;
2402 	}
2403 
2404 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2405 			xprt->address_strings[RPC_DISPLAY_ADDR],
2406 			xprt->address_strings[RPC_DISPLAY_PORT],
2407 			xprt->address_strings[RPC_DISPLAY_PROTO]);
2408 
2409 	/*
2410 	 * Once we've associated a backchannel xprt with a connection,
2411 	 * we want to keep it around as long as long as the connection
2412 	 * lasts, in case we need to start using it for a backchannel
2413 	 * again; this reference won't be dropped until bc_xprt is
2414 	 * destroyed.
2415 	 */
2416 	xprt_get(xprt);
2417 	args->bc_xprt->xpt_bc_xprt = xprt;
2418 	xprt->bc_xprt = args->bc_xprt;
2419 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
2420 	transport->sock = bc_sock->sk_sock;
2421 	transport->inet = bc_sock->sk_sk;
2422 
2423 	/*
2424 	 * Since we don't want connections for the backchannel, we set
2425 	 * the xprt status to connected
2426 	 */
2427 	xprt_set_connected(xprt);
2428 
2429 
2430 	if (try_module_get(THIS_MODULE))
2431 		return xprt;
2432 	xprt_put(xprt);
2433 	ret = ERR_PTR(-EINVAL);
2434 out_err:
2435 	xprt_free(xprt);
2436 	return ret;
2437 }
2438 
2439 static struct xprt_class	xs_udp_transport = {
2440 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
2441 	.name		= "udp",
2442 	.owner		= THIS_MODULE,
2443 	.ident		= XPRT_TRANSPORT_UDP,
2444 	.setup		= xs_setup_udp,
2445 };
2446 
2447 static struct xprt_class	xs_tcp_transport = {
2448 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
2449 	.name		= "tcp",
2450 	.owner		= THIS_MODULE,
2451 	.ident		= XPRT_TRANSPORT_TCP,
2452 	.setup		= xs_setup_tcp,
2453 };
2454 
2455 static struct xprt_class	xs_bc_tcp_transport = {
2456 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
2457 	.name		= "tcp NFSv4.1 backchannel",
2458 	.owner		= THIS_MODULE,
2459 	.ident		= XPRT_TRANSPORT_BC_TCP,
2460 	.setup		= xs_setup_bc_tcp,
2461 };
2462 
2463 /**
2464  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
2465  *
2466  */
2467 int init_socket_xprt(void)
2468 {
2469 #ifdef RPC_DEBUG
2470 	if (!sunrpc_table_header)
2471 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
2472 #endif
2473 
2474 	xprt_register_transport(&xs_udp_transport);
2475 	xprt_register_transport(&xs_tcp_transport);
2476 	xprt_register_transport(&xs_bc_tcp_transport);
2477 
2478 	return 0;
2479 }
2480 
2481 /**
2482  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
2483  *
2484  */
2485 void cleanup_socket_xprt(void)
2486 {
2487 #ifdef RPC_DEBUG
2488 	if (sunrpc_table_header) {
2489 		unregister_sysctl_table(sunrpc_table_header);
2490 		sunrpc_table_header = NULL;
2491 	}
2492 #endif
2493 
2494 	xprt_unregister_transport(&xs_udp_transport);
2495 	xprt_unregister_transport(&xs_tcp_transport);
2496 	xprt_unregister_transport(&xs_bc_tcp_transport);
2497 }
2498 
2499 static int param_set_uint_minmax(const char *val,
2500 		const struct kernel_param *kp,
2501 		unsigned int min, unsigned int max)
2502 {
2503 	unsigned long num;
2504 	int ret;
2505 
2506 	if (!val)
2507 		return -EINVAL;
2508 	ret = strict_strtoul(val, 0, &num);
2509 	if (ret == -EINVAL || num < min || num > max)
2510 		return -EINVAL;
2511 	*((unsigned int *)kp->arg) = num;
2512 	return 0;
2513 }
2514 
2515 static int param_set_portnr(const char *val, const struct kernel_param *kp)
2516 {
2517 	return param_set_uint_minmax(val, kp,
2518 			RPC_MIN_RESVPORT,
2519 			RPC_MAX_RESVPORT);
2520 }
2521 
2522 static struct kernel_param_ops param_ops_portnr = {
2523 	.set = param_set_portnr,
2524 	.get = param_get_uint,
2525 };
2526 
2527 #define param_check_portnr(name, p) \
2528 	__param_check(name, p, unsigned int);
2529 
2530 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
2531 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
2532 
2533 static int param_set_slot_table_size(const char *val,
2534 				     const struct kernel_param *kp)
2535 {
2536 	return param_set_uint_minmax(val, kp,
2537 			RPC_MIN_SLOT_TABLE,
2538 			RPC_MAX_SLOT_TABLE);
2539 }
2540 
2541 static struct kernel_param_ops param_ops_slot_table_size = {
2542 	.set = param_set_slot_table_size,
2543 	.get = param_get_uint,
2544 };
2545 
2546 #define param_check_slot_table_size(name, p) \
2547 	__param_check(name, p, unsigned int);
2548 
2549 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
2550 		   slot_table_size, 0644);
2551 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
2552 		   slot_table_size, 0644);
2553 
2554