xref: /linux/net/sunrpc/xprtsock.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
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_rearming_delayed_work(&transport->connect_worker);
774 
775 	xs_close(xprt);
776 	xs_free_peer_addresses(xprt);
777 	kfree(xprt->slot);
778 	kfree(xprt);
779 	module_put(THIS_MODULE);
780 }
781 
782 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
783 {
784 	return (struct rpc_xprt *) sk->sk_user_data;
785 }
786 
787 /**
788  * xs_udp_data_ready - "data ready" callback for UDP sockets
789  * @sk: socket with data to read
790  * @len: how much data to read
791  *
792  */
793 static void xs_udp_data_ready(struct sock *sk, int len)
794 {
795 	struct rpc_task *task;
796 	struct rpc_xprt *xprt;
797 	struct rpc_rqst *rovr;
798 	struct sk_buff *skb;
799 	int err, repsize, copied;
800 	u32 _xid;
801 	__be32 *xp;
802 
803 	read_lock(&sk->sk_callback_lock);
804 	dprintk("RPC:       xs_udp_data_ready...\n");
805 	if (!(xprt = xprt_from_sock(sk)))
806 		goto out;
807 
808 	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
809 		goto out;
810 
811 	if (xprt->shutdown)
812 		goto dropit;
813 
814 	repsize = skb->len - sizeof(struct udphdr);
815 	if (repsize < 4) {
816 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
817 		goto dropit;
818 	}
819 
820 	/* Copy the XID from the skb... */
821 	xp = skb_header_pointer(skb, sizeof(struct udphdr),
822 				sizeof(_xid), &_xid);
823 	if (xp == NULL)
824 		goto dropit;
825 
826 	/* Look up and lock the request corresponding to the given XID */
827 	spin_lock(&xprt->transport_lock);
828 	rovr = xprt_lookup_rqst(xprt, *xp);
829 	if (!rovr)
830 		goto out_unlock;
831 	task = rovr->rq_task;
832 
833 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
834 		copied = repsize;
835 
836 	/* Suck it into the iovec, verify checksum if not done by hw. */
837 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
838 		UDPX_INC_STATS_BH(sk, UDP_MIB_INERRORS);
839 		goto out_unlock;
840 	}
841 
842 	UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
843 
844 	/* Something worked... */
845 	dst_confirm(skb_dst(skb));
846 
847 	xprt_adjust_cwnd(task, copied);
848 	xprt_complete_rqst(task, copied);
849 
850  out_unlock:
851 	spin_unlock(&xprt->transport_lock);
852  dropit:
853 	skb_free_datagram(sk, skb);
854  out:
855 	read_unlock(&sk->sk_callback_lock);
856 }
857 
858 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
859 {
860 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
861 	size_t len, used;
862 	char *p;
863 
864 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
865 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
866 	used = xdr_skb_read_bits(desc, p, len);
867 	transport->tcp_offset += used;
868 	if (used != len)
869 		return;
870 
871 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
872 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
873 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
874 	else
875 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
876 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
877 
878 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
879 	transport->tcp_offset = 0;
880 
881 	/* Sanity check of the record length */
882 	if (unlikely(transport->tcp_reclen < 8)) {
883 		dprintk("RPC:       invalid TCP record fragment length\n");
884 		xprt_force_disconnect(xprt);
885 		return;
886 	}
887 	dprintk("RPC:       reading TCP record fragment of length %d\n",
888 			transport->tcp_reclen);
889 }
890 
891 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
892 {
893 	if (transport->tcp_offset == transport->tcp_reclen) {
894 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
895 		transport->tcp_offset = 0;
896 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
897 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
898 			transport->tcp_flags |= TCP_RCV_COPY_XID;
899 			transport->tcp_copied = 0;
900 		}
901 	}
902 }
903 
904 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
905 {
906 	size_t len, used;
907 	char *p;
908 
909 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
910 	dprintk("RPC:       reading XID (%Zu bytes)\n", len);
911 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
912 	used = xdr_skb_read_bits(desc, p, len);
913 	transport->tcp_offset += used;
914 	if (used != len)
915 		return;
916 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
917 	transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
918 	transport->tcp_copied = 4;
919 	dprintk("RPC:       reading %s XID %08x\n",
920 			(transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
921 							      : "request with",
922 			ntohl(transport->tcp_xid));
923 	xs_tcp_check_fraghdr(transport);
924 }
925 
926 static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
927 				       struct xdr_skb_reader *desc)
928 {
929 	size_t len, used;
930 	u32 offset;
931 	char *p;
932 
933 	/*
934 	 * We want transport->tcp_offset to be 8 at the end of this routine
935 	 * (4 bytes for the xid and 4 bytes for the call/reply flag).
936 	 * When this function is called for the first time,
937 	 * transport->tcp_offset is 4 (after having already read the xid).
938 	 */
939 	offset = transport->tcp_offset - sizeof(transport->tcp_xid);
940 	len = sizeof(transport->tcp_calldir) - offset;
941 	dprintk("RPC:       reading CALL/REPLY flag (%Zu bytes)\n", len);
942 	p = ((char *) &transport->tcp_calldir) + offset;
943 	used = xdr_skb_read_bits(desc, p, len);
944 	transport->tcp_offset += used;
945 	if (used != len)
946 		return;
947 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
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 	switch (ntohl(transport->tcp_calldir)) {
953 	case RPC_REPLY:
954 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
955 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
956 		transport->tcp_flags |= TCP_RPC_REPLY;
957 		break;
958 	case RPC_CALL:
959 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
960 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
961 		transport->tcp_flags &= ~TCP_RPC_REPLY;
962 		break;
963 	default:
964 		dprintk("RPC:       invalid request message type\n");
965 		xprt_force_disconnect(&transport->xprt);
966 	}
967 	xs_tcp_check_fraghdr(transport);
968 }
969 
970 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
971 				     struct xdr_skb_reader *desc,
972 				     struct rpc_rqst *req)
973 {
974 	struct sock_xprt *transport =
975 				container_of(xprt, struct sock_xprt, xprt);
976 	struct xdr_buf *rcvbuf;
977 	size_t len;
978 	ssize_t r;
979 
980 	rcvbuf = &req->rq_private_buf;
981 
982 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
983 		/*
984 		 * Save the RPC direction in the XDR buffer
985 		 */
986 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
987 			&transport->tcp_calldir,
988 			sizeof(transport->tcp_calldir));
989 		transport->tcp_copied += sizeof(transport->tcp_calldir);
990 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
991 	}
992 
993 	len = desc->count;
994 	if (len > transport->tcp_reclen - transport->tcp_offset) {
995 		struct xdr_skb_reader my_desc;
996 
997 		len = transport->tcp_reclen - transport->tcp_offset;
998 		memcpy(&my_desc, desc, sizeof(my_desc));
999 		my_desc.count = len;
1000 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1001 					  &my_desc, xdr_skb_read_bits);
1002 		desc->count -= r;
1003 		desc->offset += r;
1004 	} else
1005 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1006 					  desc, xdr_skb_read_bits);
1007 
1008 	if (r > 0) {
1009 		transport->tcp_copied += r;
1010 		transport->tcp_offset += r;
1011 	}
1012 	if (r != len) {
1013 		/* Error when copying to the receive buffer,
1014 		 * usually because we weren't able to allocate
1015 		 * additional buffer pages. All we can do now
1016 		 * is turn off TCP_RCV_COPY_DATA, so the request
1017 		 * will not receive any additional updates,
1018 		 * and time out.
1019 		 * Any remaining data from this record will
1020 		 * be discarded.
1021 		 */
1022 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1023 		dprintk("RPC:       XID %08x truncated request\n",
1024 				ntohl(transport->tcp_xid));
1025 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1026 				"tcp_offset = %u, tcp_reclen = %u\n",
1027 				xprt, transport->tcp_copied,
1028 				transport->tcp_offset, transport->tcp_reclen);
1029 		return;
1030 	}
1031 
1032 	dprintk("RPC:       XID %08x read %Zd bytes\n",
1033 			ntohl(transport->tcp_xid), r);
1034 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1035 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1036 			transport->tcp_offset, transport->tcp_reclen);
1037 
1038 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1039 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1040 	else if (transport->tcp_offset == transport->tcp_reclen) {
1041 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1042 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1043 	}
1044 }
1045 
1046 /*
1047  * Finds the request corresponding to the RPC xid and invokes the common
1048  * tcp read code to read the data.
1049  */
1050 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1051 				    struct xdr_skb_reader *desc)
1052 {
1053 	struct sock_xprt *transport =
1054 				container_of(xprt, struct sock_xprt, xprt);
1055 	struct rpc_rqst *req;
1056 
1057 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1058 
1059 	/* Find and lock the request corresponding to this xid */
1060 	spin_lock(&xprt->transport_lock);
1061 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1062 	if (!req) {
1063 		dprintk("RPC:       XID %08x request not found!\n",
1064 				ntohl(transport->tcp_xid));
1065 		spin_unlock(&xprt->transport_lock);
1066 		return -1;
1067 	}
1068 
1069 	xs_tcp_read_common(xprt, desc, req);
1070 
1071 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1072 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1073 
1074 	spin_unlock(&xprt->transport_lock);
1075 	return 0;
1076 }
1077 
1078 #if defined(CONFIG_NFS_V4_1)
1079 /*
1080  * Obtains an rpc_rqst previously allocated and invokes the common
1081  * tcp read code to read the data.  The result is placed in the callback
1082  * queue.
1083  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1084  * connection and return -1.
1085  */
1086 static inline int xs_tcp_read_callback(struct rpc_xprt *xprt,
1087 				       struct xdr_skb_reader *desc)
1088 {
1089 	struct sock_xprt *transport =
1090 				container_of(xprt, struct sock_xprt, xprt);
1091 	struct rpc_rqst *req;
1092 
1093 	req = xprt_alloc_bc_request(xprt);
1094 	if (req == NULL) {
1095 		printk(KERN_WARNING "Callback slot table overflowed\n");
1096 		xprt_force_disconnect(xprt);
1097 		return -1;
1098 	}
1099 
1100 	req->rq_xid = transport->tcp_xid;
1101 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1102 	xs_tcp_read_common(xprt, desc, req);
1103 
1104 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) {
1105 		struct svc_serv *bc_serv = xprt->bc_serv;
1106 
1107 		/*
1108 		 * Add callback request to callback list.  The callback
1109 		 * service sleeps on the sv_cb_waitq waiting for new
1110 		 * requests.  Wake it up after adding enqueing the
1111 		 * request.
1112 		 */
1113 		dprintk("RPC:       add callback request to list\n");
1114 		spin_lock(&bc_serv->sv_cb_lock);
1115 		list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
1116 		spin_unlock(&bc_serv->sv_cb_lock);
1117 		wake_up(&bc_serv->sv_cb_waitq);
1118 	}
1119 
1120 	req->rq_private_buf.len = transport->tcp_copied;
1121 
1122 	return 0;
1123 }
1124 
1125 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1126 					struct xdr_skb_reader *desc)
1127 {
1128 	struct sock_xprt *transport =
1129 				container_of(xprt, struct sock_xprt, xprt);
1130 
1131 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1132 		xs_tcp_read_reply(xprt, desc) :
1133 		xs_tcp_read_callback(xprt, desc);
1134 }
1135 #else
1136 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1137 					struct xdr_skb_reader *desc)
1138 {
1139 	return xs_tcp_read_reply(xprt, desc);
1140 }
1141 #endif /* CONFIG_NFS_V4_1 */
1142 
1143 /*
1144  * Read data off the transport.  This can be either an RPC_CALL or an
1145  * RPC_REPLY.  Relay the processing to helper functions.
1146  */
1147 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1148 				    struct xdr_skb_reader *desc)
1149 {
1150 	struct sock_xprt *transport =
1151 				container_of(xprt, struct sock_xprt, xprt);
1152 
1153 	if (_xs_tcp_read_data(xprt, desc) == 0)
1154 		xs_tcp_check_fraghdr(transport);
1155 	else {
1156 		/*
1157 		 * The transport_lock protects the request handling.
1158 		 * There's no need to hold it to update the tcp_flags.
1159 		 */
1160 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1161 	}
1162 }
1163 
1164 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1165 {
1166 	size_t len;
1167 
1168 	len = transport->tcp_reclen - transport->tcp_offset;
1169 	if (len > desc->count)
1170 		len = desc->count;
1171 	desc->count -= len;
1172 	desc->offset += len;
1173 	transport->tcp_offset += len;
1174 	dprintk("RPC:       discarded %Zu bytes\n", len);
1175 	xs_tcp_check_fraghdr(transport);
1176 }
1177 
1178 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1179 {
1180 	struct rpc_xprt *xprt = rd_desc->arg.data;
1181 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1182 	struct xdr_skb_reader desc = {
1183 		.skb	= skb,
1184 		.offset	= offset,
1185 		.count	= len,
1186 	};
1187 
1188 	dprintk("RPC:       xs_tcp_data_recv started\n");
1189 	do {
1190 		/* Read in a new fragment marker if necessary */
1191 		/* Can we ever really expect to get completely empty fragments? */
1192 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1193 			xs_tcp_read_fraghdr(xprt, &desc);
1194 			continue;
1195 		}
1196 		/* Read in the xid if necessary */
1197 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1198 			xs_tcp_read_xid(transport, &desc);
1199 			continue;
1200 		}
1201 		/* Read in the call/reply flag */
1202 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1203 			xs_tcp_read_calldir(transport, &desc);
1204 			continue;
1205 		}
1206 		/* Read in the request data */
1207 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1208 			xs_tcp_read_data(xprt, &desc);
1209 			continue;
1210 		}
1211 		/* Skip over any trailing bytes on short reads */
1212 		xs_tcp_read_discard(transport, &desc);
1213 	} while (desc.count);
1214 	dprintk("RPC:       xs_tcp_data_recv done\n");
1215 	return len - desc.count;
1216 }
1217 
1218 /**
1219  * xs_tcp_data_ready - "data ready" callback for TCP sockets
1220  * @sk: socket with data to read
1221  * @bytes: how much data to read
1222  *
1223  */
1224 static void xs_tcp_data_ready(struct sock *sk, int bytes)
1225 {
1226 	struct rpc_xprt *xprt;
1227 	read_descriptor_t rd_desc;
1228 	int read;
1229 
1230 	dprintk("RPC:       xs_tcp_data_ready...\n");
1231 
1232 	read_lock(&sk->sk_callback_lock);
1233 	if (!(xprt = xprt_from_sock(sk)))
1234 		goto out;
1235 	if (xprt->shutdown)
1236 		goto out;
1237 
1238 	/* Any data means we had a useful conversation, so
1239 	 * the we don't need to delay the next reconnect
1240 	 */
1241 	if (xprt->reestablish_timeout)
1242 		xprt->reestablish_timeout = 0;
1243 
1244 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1245 	rd_desc.arg.data = xprt;
1246 	do {
1247 		rd_desc.count = 65536;
1248 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1249 	} while (read > 0);
1250 out:
1251 	read_unlock(&sk->sk_callback_lock);
1252 }
1253 
1254 /*
1255  * Do the equivalent of linger/linger2 handling for dealing with
1256  * broken servers that don't close the socket in a timely
1257  * fashion
1258  */
1259 static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt,
1260 		unsigned long timeout)
1261 {
1262 	struct sock_xprt *transport;
1263 
1264 	if (xprt_test_and_set_connecting(xprt))
1265 		return;
1266 	set_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1267 	transport = container_of(xprt, struct sock_xprt, xprt);
1268 	queue_delayed_work(rpciod_workqueue, &transport->connect_worker,
1269 			   timeout);
1270 }
1271 
1272 static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
1273 {
1274 	struct sock_xprt *transport;
1275 
1276 	transport = container_of(xprt, struct sock_xprt, xprt);
1277 
1278 	if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) ||
1279 	    !cancel_delayed_work(&transport->connect_worker))
1280 		return;
1281 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1282 	xprt_clear_connecting(xprt);
1283 }
1284 
1285 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
1286 {
1287 	smp_mb__before_clear_bit();
1288 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1289 	clear_bit(XPRT_CLOSING, &xprt->state);
1290 	smp_mb__after_clear_bit();
1291 	/* Mark transport as closed and wake up all pending tasks */
1292 	xprt_disconnect_done(xprt);
1293 }
1294 
1295 /**
1296  * xs_tcp_state_change - callback to handle TCP socket state changes
1297  * @sk: socket whose state has changed
1298  *
1299  */
1300 static void xs_tcp_state_change(struct sock *sk)
1301 {
1302 	struct rpc_xprt *xprt;
1303 
1304 	read_lock(&sk->sk_callback_lock);
1305 	if (!(xprt = xprt_from_sock(sk)))
1306 		goto out;
1307 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1308 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1309 			sk->sk_state, xprt_connected(xprt),
1310 			sock_flag(sk, SOCK_DEAD),
1311 			sock_flag(sk, SOCK_ZAPPED),
1312 			sk->sk_shutdown);
1313 
1314 	switch (sk->sk_state) {
1315 	case TCP_ESTABLISHED:
1316 		spin_lock_bh(&xprt->transport_lock);
1317 		if (!xprt_test_and_set_connected(xprt)) {
1318 			struct sock_xprt *transport = container_of(xprt,
1319 					struct sock_xprt, xprt);
1320 
1321 			/* Reset TCP record info */
1322 			transport->tcp_offset = 0;
1323 			transport->tcp_reclen = 0;
1324 			transport->tcp_copied = 0;
1325 			transport->tcp_flags =
1326 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1327 
1328 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1329 		}
1330 		spin_unlock_bh(&xprt->transport_lock);
1331 		break;
1332 	case TCP_FIN_WAIT1:
1333 		/* The client initiated a shutdown of the socket */
1334 		xprt->connect_cookie++;
1335 		xprt->reestablish_timeout = 0;
1336 		set_bit(XPRT_CLOSING, &xprt->state);
1337 		smp_mb__before_clear_bit();
1338 		clear_bit(XPRT_CONNECTED, &xprt->state);
1339 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1340 		smp_mb__after_clear_bit();
1341 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1342 		break;
1343 	case TCP_CLOSE_WAIT:
1344 		/* The server initiated a shutdown of the socket */
1345 		xprt_force_disconnect(xprt);
1346 	case TCP_SYN_SENT:
1347 		xprt->connect_cookie++;
1348 	case TCP_CLOSING:
1349 		/*
1350 		 * If the server closed down the connection, make sure that
1351 		 * we back off before reconnecting
1352 		 */
1353 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1354 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1355 		break;
1356 	case TCP_LAST_ACK:
1357 		set_bit(XPRT_CLOSING, &xprt->state);
1358 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1359 		smp_mb__before_clear_bit();
1360 		clear_bit(XPRT_CONNECTED, &xprt->state);
1361 		smp_mb__after_clear_bit();
1362 		break;
1363 	case TCP_CLOSE:
1364 		xs_tcp_cancel_linger_timeout(xprt);
1365 		xs_sock_mark_closed(xprt);
1366 	}
1367  out:
1368 	read_unlock(&sk->sk_callback_lock);
1369 }
1370 
1371 /**
1372  * xs_error_report - callback mainly for catching socket errors
1373  * @sk: socket
1374  */
1375 static void xs_error_report(struct sock *sk)
1376 {
1377 	struct rpc_xprt *xprt;
1378 
1379 	read_lock(&sk->sk_callback_lock);
1380 	if (!(xprt = xprt_from_sock(sk)))
1381 		goto out;
1382 	dprintk("RPC:       %s client %p...\n"
1383 			"RPC:       error %d\n",
1384 			__func__, xprt, sk->sk_err);
1385 	xprt_wake_pending_tasks(xprt, -EAGAIN);
1386 out:
1387 	read_unlock(&sk->sk_callback_lock);
1388 }
1389 
1390 static void xs_write_space(struct sock *sk)
1391 {
1392 	struct socket *sock;
1393 	struct rpc_xprt *xprt;
1394 
1395 	if (unlikely(!(sock = sk->sk_socket)))
1396 		return;
1397 	clear_bit(SOCK_NOSPACE, &sock->flags);
1398 
1399 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1400 		return;
1401 	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
1402 		return;
1403 
1404 	xprt_write_space(xprt);
1405 }
1406 
1407 /**
1408  * xs_udp_write_space - callback invoked when socket buffer space
1409  *                             becomes available
1410  * @sk: socket whose state has changed
1411  *
1412  * Called when more output buffer space is available for this socket.
1413  * We try not to wake our writers until they can make "significant"
1414  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1415  * with a bunch of small requests.
1416  */
1417 static void xs_udp_write_space(struct sock *sk)
1418 {
1419 	read_lock(&sk->sk_callback_lock);
1420 
1421 	/* from net/core/sock.c:sock_def_write_space */
1422 	if (sock_writeable(sk))
1423 		xs_write_space(sk);
1424 
1425 	read_unlock(&sk->sk_callback_lock);
1426 }
1427 
1428 /**
1429  * xs_tcp_write_space - callback invoked when socket buffer space
1430  *                             becomes available
1431  * @sk: socket whose state has changed
1432  *
1433  * Called when more output buffer space is available for this socket.
1434  * We try not to wake our writers until they can make "significant"
1435  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1436  * with a bunch of small requests.
1437  */
1438 static void xs_tcp_write_space(struct sock *sk)
1439 {
1440 	read_lock(&sk->sk_callback_lock);
1441 
1442 	/* from net/core/stream.c:sk_stream_write_space */
1443 	if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
1444 		xs_write_space(sk);
1445 
1446 	read_unlock(&sk->sk_callback_lock);
1447 }
1448 
1449 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1450 {
1451 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1452 	struct sock *sk = transport->inet;
1453 
1454 	if (transport->rcvsize) {
1455 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1456 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1457 	}
1458 	if (transport->sndsize) {
1459 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1460 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1461 		sk->sk_write_space(sk);
1462 	}
1463 }
1464 
1465 /**
1466  * xs_udp_set_buffer_size - set send and receive limits
1467  * @xprt: generic transport
1468  * @sndsize: requested size of send buffer, in bytes
1469  * @rcvsize: requested size of receive buffer, in bytes
1470  *
1471  * Set socket send and receive buffer size limits.
1472  */
1473 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1474 {
1475 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1476 
1477 	transport->sndsize = 0;
1478 	if (sndsize)
1479 		transport->sndsize = sndsize + 1024;
1480 	transport->rcvsize = 0;
1481 	if (rcvsize)
1482 		transport->rcvsize = rcvsize + 1024;
1483 
1484 	xs_udp_do_set_buffer_size(xprt);
1485 }
1486 
1487 /**
1488  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1489  * @task: task that timed out
1490  *
1491  * Adjust the congestion window after a retransmit timeout has occurred.
1492  */
1493 static void xs_udp_timer(struct rpc_task *task)
1494 {
1495 	xprt_adjust_cwnd(task, -ETIMEDOUT);
1496 }
1497 
1498 static unsigned short xs_get_random_port(void)
1499 {
1500 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1501 	unsigned short rand = (unsigned short) net_random() % range;
1502 	return rand + xprt_min_resvport;
1503 }
1504 
1505 /**
1506  * xs_set_port - reset the port number in the remote endpoint address
1507  * @xprt: generic transport
1508  * @port: new port number
1509  *
1510  */
1511 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1512 {
1513 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1514 
1515 	rpc_set_port(xs_addr(xprt), port);
1516 	xs_update_peer_port(xprt);
1517 }
1518 
1519 static unsigned short xs_get_srcport(struct sock_xprt *transport, struct socket *sock)
1520 {
1521 	unsigned short port = transport->srcport;
1522 
1523 	if (port == 0 && transport->xprt.resvport)
1524 		port = xs_get_random_port();
1525 	return port;
1526 }
1527 
1528 static unsigned short xs_next_srcport(struct sock_xprt *transport, struct socket *sock, unsigned short port)
1529 {
1530 	if (transport->srcport != 0)
1531 		transport->srcport = 0;
1532 	if (!transport->xprt.resvport)
1533 		return 0;
1534 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1535 		return xprt_max_resvport;
1536 	return --port;
1537 }
1538 
1539 static int xs_bind4(struct sock_xprt *transport, struct socket *sock)
1540 {
1541 	struct sockaddr_in myaddr = {
1542 		.sin_family = AF_INET,
1543 	};
1544 	struct sockaddr_in *sa;
1545 	int err, nloop = 0;
1546 	unsigned short port = xs_get_srcport(transport, sock);
1547 	unsigned short last;
1548 
1549 	sa = (struct sockaddr_in *)&transport->srcaddr;
1550 	myaddr.sin_addr = sa->sin_addr;
1551 	do {
1552 		myaddr.sin_port = htons(port);
1553 		err = kernel_bind(sock, (struct sockaddr *) &myaddr,
1554 						sizeof(myaddr));
1555 		if (port == 0)
1556 			break;
1557 		if (err == 0) {
1558 			transport->srcport = port;
1559 			break;
1560 		}
1561 		last = port;
1562 		port = xs_next_srcport(transport, sock, port);
1563 		if (port > last)
1564 			nloop++;
1565 	} while (err == -EADDRINUSE && nloop != 2);
1566 	dprintk("RPC:       %s %pI4:%u: %s (%d)\n",
1567 			__func__, &myaddr.sin_addr,
1568 			port, err ? "failed" : "ok", err);
1569 	return err;
1570 }
1571 
1572 static int xs_bind6(struct sock_xprt *transport, struct socket *sock)
1573 {
1574 	struct sockaddr_in6 myaddr = {
1575 		.sin6_family = AF_INET6,
1576 	};
1577 	struct sockaddr_in6 *sa;
1578 	int err, nloop = 0;
1579 	unsigned short port = xs_get_srcport(transport, sock);
1580 	unsigned short last;
1581 
1582 	sa = (struct sockaddr_in6 *)&transport->srcaddr;
1583 	myaddr.sin6_addr = sa->sin6_addr;
1584 	do {
1585 		myaddr.sin6_port = htons(port);
1586 		err = kernel_bind(sock, (struct sockaddr *) &myaddr,
1587 						sizeof(myaddr));
1588 		if (port == 0)
1589 			break;
1590 		if (err == 0) {
1591 			transport->srcport = port;
1592 			break;
1593 		}
1594 		last = port;
1595 		port = xs_next_srcport(transport, sock, port);
1596 		if (port > last)
1597 			nloop++;
1598 	} while (err == -EADDRINUSE && nloop != 2);
1599 	dprintk("RPC:       xs_bind6 %pI6:%u: %s (%d)\n",
1600 		&myaddr.sin6_addr, port, err ? "failed" : "ok", err);
1601 	return err;
1602 }
1603 
1604 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1605 static struct lock_class_key xs_key[2];
1606 static struct lock_class_key xs_slock_key[2];
1607 
1608 static inline void xs_reclassify_socket4(struct socket *sock)
1609 {
1610 	struct sock *sk = sock->sk;
1611 
1612 	BUG_ON(sock_owned_by_user(sk));
1613 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1614 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1615 }
1616 
1617 static inline void xs_reclassify_socket6(struct socket *sock)
1618 {
1619 	struct sock *sk = sock->sk;
1620 
1621 	BUG_ON(sock_owned_by_user(sk));
1622 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1623 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1624 }
1625 #else
1626 static inline void xs_reclassify_socket4(struct socket *sock)
1627 {
1628 }
1629 
1630 static inline void xs_reclassify_socket6(struct socket *sock)
1631 {
1632 }
1633 #endif
1634 
1635 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1636 {
1637 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1638 
1639 	if (!transport->inet) {
1640 		struct sock *sk = sock->sk;
1641 
1642 		write_lock_bh(&sk->sk_callback_lock);
1643 
1644 		xs_save_old_callbacks(transport, sk);
1645 
1646 		sk->sk_user_data = xprt;
1647 		sk->sk_data_ready = xs_udp_data_ready;
1648 		sk->sk_write_space = xs_udp_write_space;
1649 		sk->sk_error_report = xs_error_report;
1650 		sk->sk_no_check = UDP_CSUM_NORCV;
1651 		sk->sk_allocation = GFP_ATOMIC;
1652 
1653 		xprt_set_connected(xprt);
1654 
1655 		/* Reset to new socket */
1656 		transport->sock = sock;
1657 		transport->inet = sk;
1658 
1659 		write_unlock_bh(&sk->sk_callback_lock);
1660 	}
1661 	xs_udp_do_set_buffer_size(xprt);
1662 }
1663 
1664 /**
1665  * xs_udp_connect_worker4 - set up a UDP socket
1666  * @work: RPC transport to connect
1667  *
1668  * Invoked by a work queue tasklet.
1669  */
1670 static void xs_udp_connect_worker4(struct work_struct *work)
1671 {
1672 	struct sock_xprt *transport =
1673 		container_of(work, struct sock_xprt, connect_worker.work);
1674 	struct rpc_xprt *xprt = &transport->xprt;
1675 	struct socket *sock = transport->sock;
1676 	int err, status = -EIO;
1677 
1678 	if (xprt->shutdown)
1679 		goto out;
1680 
1681 	/* Start by resetting any existing state */
1682 	xs_reset_transport(transport);
1683 
1684 	err = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
1685 	if (err < 0) {
1686 		dprintk("RPC:       can't create UDP transport socket (%d).\n", -err);
1687 		goto out;
1688 	}
1689 	xs_reclassify_socket4(sock);
1690 
1691 	if (xs_bind4(transport, sock)) {
1692 		sock_release(sock);
1693 		goto out;
1694 	}
1695 
1696 	dprintk("RPC:       worker connecting xprt %p via %s to "
1697 				"%s (port %s)\n", xprt,
1698 			xprt->address_strings[RPC_DISPLAY_PROTO],
1699 			xprt->address_strings[RPC_DISPLAY_ADDR],
1700 			xprt->address_strings[RPC_DISPLAY_PORT]);
1701 
1702 	xs_udp_finish_connecting(xprt, sock);
1703 	status = 0;
1704 out:
1705 	xprt_clear_connecting(xprt);
1706 	xprt_wake_pending_tasks(xprt, status);
1707 }
1708 
1709 /**
1710  * xs_udp_connect_worker6 - set up a UDP socket
1711  * @work: RPC transport to connect
1712  *
1713  * Invoked by a work queue tasklet.
1714  */
1715 static void xs_udp_connect_worker6(struct work_struct *work)
1716 {
1717 	struct sock_xprt *transport =
1718 		container_of(work, struct sock_xprt, connect_worker.work);
1719 	struct rpc_xprt *xprt = &transport->xprt;
1720 	struct socket *sock = transport->sock;
1721 	int err, status = -EIO;
1722 
1723 	if (xprt->shutdown)
1724 		goto out;
1725 
1726 	/* Start by resetting any existing state */
1727 	xs_reset_transport(transport);
1728 
1729 	err = sock_create_kern(PF_INET6, SOCK_DGRAM, IPPROTO_UDP, &sock);
1730 	if (err < 0) {
1731 		dprintk("RPC:       can't create UDP transport socket (%d).\n", -err);
1732 		goto out;
1733 	}
1734 	xs_reclassify_socket6(sock);
1735 
1736 	if (xs_bind6(transport, sock) < 0) {
1737 		sock_release(sock);
1738 		goto out;
1739 	}
1740 
1741 	dprintk("RPC:       worker connecting xprt %p via %s to "
1742 				"%s (port %s)\n", xprt,
1743 			xprt->address_strings[RPC_DISPLAY_PROTO],
1744 			xprt->address_strings[RPC_DISPLAY_ADDR],
1745 			xprt->address_strings[RPC_DISPLAY_PORT]);
1746 
1747 	xs_udp_finish_connecting(xprt, sock);
1748 	status = 0;
1749 out:
1750 	xprt_clear_connecting(xprt);
1751 	xprt_wake_pending_tasks(xprt, status);
1752 }
1753 
1754 /*
1755  * We need to preserve the port number so the reply cache on the server can
1756  * find our cached RPC replies when we get around to reconnecting.
1757  */
1758 static void xs_abort_connection(struct rpc_xprt *xprt, struct sock_xprt *transport)
1759 {
1760 	int result;
1761 	struct sockaddr any;
1762 
1763 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", xprt);
1764 
1765 	/*
1766 	 * Disconnect the transport socket by doing a connect operation
1767 	 * with AF_UNSPEC.  This should return immediately...
1768 	 */
1769 	memset(&any, 0, sizeof(any));
1770 	any.sa_family = AF_UNSPEC;
1771 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
1772 	if (!result)
1773 		xs_sock_mark_closed(xprt);
1774 	else
1775 		dprintk("RPC:       AF_UNSPEC connect return code %d\n",
1776 				result);
1777 }
1778 
1779 static void xs_tcp_reuse_connection(struct rpc_xprt *xprt, struct sock_xprt *transport)
1780 {
1781 	unsigned int state = transport->inet->sk_state;
1782 
1783 	if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED) {
1784 		/* we don't need to abort the connection if the socket
1785 		 * hasn't undergone a shutdown
1786 		 */
1787 		if (transport->inet->sk_shutdown == 0)
1788 			return;
1789 		dprintk("RPC:       %s: TCP_CLOSEd and sk_shutdown set to %d\n",
1790 				__func__, transport->inet->sk_shutdown);
1791 	}
1792 	if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT)) {
1793 		/* we don't need to abort the connection if the socket
1794 		 * hasn't undergone a shutdown
1795 		 */
1796 		if (transport->inet->sk_shutdown == 0)
1797 			return;
1798 		dprintk("RPC:       %s: ESTABLISHED/SYN_SENT "
1799 				"sk_shutdown set to %d\n",
1800 				__func__, transport->inet->sk_shutdown);
1801 	}
1802 	xs_abort_connection(xprt, transport);
1803 }
1804 
1805 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1806 {
1807 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1808 
1809 	if (!transport->inet) {
1810 		struct sock *sk = sock->sk;
1811 
1812 		write_lock_bh(&sk->sk_callback_lock);
1813 
1814 		xs_save_old_callbacks(transport, sk);
1815 
1816 		sk->sk_user_data = xprt;
1817 		sk->sk_data_ready = xs_tcp_data_ready;
1818 		sk->sk_state_change = xs_tcp_state_change;
1819 		sk->sk_write_space = xs_tcp_write_space;
1820 		sk->sk_error_report = xs_error_report;
1821 		sk->sk_allocation = GFP_ATOMIC;
1822 
1823 		/* socket options */
1824 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
1825 		sock_reset_flag(sk, SOCK_LINGER);
1826 		tcp_sk(sk)->linger2 = 0;
1827 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
1828 
1829 		xprt_clear_connected(xprt);
1830 
1831 		/* Reset to new socket */
1832 		transport->sock = sock;
1833 		transport->inet = sk;
1834 
1835 		write_unlock_bh(&sk->sk_callback_lock);
1836 	}
1837 
1838 	if (!xprt_bound(xprt))
1839 		return -ENOTCONN;
1840 
1841 	/* Tell the socket layer to start connecting... */
1842 	xprt->stat.connect_count++;
1843 	xprt->stat.connect_start = jiffies;
1844 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
1845 }
1846 
1847 /**
1848  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
1849  * @xprt: RPC transport to connect
1850  * @transport: socket transport to connect
1851  * @create_sock: function to create a socket of the correct type
1852  *
1853  * Invoked by a work queue tasklet.
1854  */
1855 static void xs_tcp_setup_socket(struct rpc_xprt *xprt,
1856 		struct sock_xprt *transport,
1857 		struct socket *(*create_sock)(struct rpc_xprt *,
1858 			struct sock_xprt *))
1859 {
1860 	struct socket *sock = transport->sock;
1861 	int status = -EIO;
1862 
1863 	if (xprt->shutdown)
1864 		goto out;
1865 
1866 	if (!sock) {
1867 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1868 		sock = create_sock(xprt, transport);
1869 		if (IS_ERR(sock)) {
1870 			status = PTR_ERR(sock);
1871 			goto out;
1872 		}
1873 	} else {
1874 		int abort_and_exit;
1875 
1876 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
1877 				&xprt->state);
1878 		/* "close" the socket, preserving the local port */
1879 		xs_tcp_reuse_connection(xprt, transport);
1880 
1881 		if (abort_and_exit)
1882 			goto out_eagain;
1883 	}
1884 
1885 	dprintk("RPC:       worker connecting xprt %p via %s to "
1886 				"%s (port %s)\n", xprt,
1887 			xprt->address_strings[RPC_DISPLAY_PROTO],
1888 			xprt->address_strings[RPC_DISPLAY_ADDR],
1889 			xprt->address_strings[RPC_DISPLAY_PORT]);
1890 
1891 	status = xs_tcp_finish_connecting(xprt, sock);
1892 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
1893 			xprt, -status, xprt_connected(xprt),
1894 			sock->sk->sk_state);
1895 	switch (status) {
1896 	default:
1897 		printk("%s: connect returned unhandled error %d\n",
1898 			__func__, status);
1899 	case -EADDRNOTAVAIL:
1900 		/* We're probably in TIME_WAIT. Get rid of existing socket,
1901 		 * and retry
1902 		 */
1903 		set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1904 		xprt_force_disconnect(xprt);
1905 		break;
1906 	case -ECONNREFUSED:
1907 	case -ECONNRESET:
1908 	case -ENETUNREACH:
1909 		/* retry with existing socket, after a delay */
1910 	case 0:
1911 	case -EINPROGRESS:
1912 	case -EALREADY:
1913 		xprt_clear_connecting(xprt);
1914 		return;
1915 	case -EINVAL:
1916 		/* Happens, for instance, if the user specified a link
1917 		 * local IPv6 address without a scope-id.
1918 		 */
1919 		goto out;
1920 	}
1921 out_eagain:
1922 	status = -EAGAIN;
1923 out:
1924 	xprt_clear_connecting(xprt);
1925 	xprt_wake_pending_tasks(xprt, status);
1926 }
1927 
1928 static struct socket *xs_create_tcp_sock4(struct rpc_xprt *xprt,
1929 		struct sock_xprt *transport)
1930 {
1931 	struct socket *sock;
1932 	int err;
1933 
1934 	/* start from scratch */
1935 	err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1936 	if (err < 0) {
1937 		dprintk("RPC:       can't create TCP transport socket (%d).\n",
1938 				-err);
1939 		goto out_err;
1940 	}
1941 	xs_reclassify_socket4(sock);
1942 
1943 	if (xs_bind4(transport, sock) < 0) {
1944 		sock_release(sock);
1945 		goto out_err;
1946 	}
1947 	return sock;
1948 out_err:
1949 	return ERR_PTR(-EIO);
1950 }
1951 
1952 /**
1953  * xs_tcp_connect_worker4 - connect a TCP socket to a remote endpoint
1954  * @work: RPC transport to connect
1955  *
1956  * Invoked by a work queue tasklet.
1957  */
1958 static void xs_tcp_connect_worker4(struct work_struct *work)
1959 {
1960 	struct sock_xprt *transport =
1961 		container_of(work, struct sock_xprt, connect_worker.work);
1962 	struct rpc_xprt *xprt = &transport->xprt;
1963 
1964 	xs_tcp_setup_socket(xprt, transport, xs_create_tcp_sock4);
1965 }
1966 
1967 static struct socket *xs_create_tcp_sock6(struct rpc_xprt *xprt,
1968 		struct sock_xprt *transport)
1969 {
1970 	struct socket *sock;
1971 	int err;
1972 
1973 	/* start from scratch */
1974 	err = sock_create_kern(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &sock);
1975 	if (err < 0) {
1976 		dprintk("RPC:       can't create TCP transport socket (%d).\n",
1977 				-err);
1978 		goto out_err;
1979 	}
1980 	xs_reclassify_socket6(sock);
1981 
1982 	if (xs_bind6(transport, sock) < 0) {
1983 		sock_release(sock);
1984 		goto out_err;
1985 	}
1986 	return sock;
1987 out_err:
1988 	return ERR_PTR(-EIO);
1989 }
1990 
1991 /**
1992  * xs_tcp_connect_worker6 - connect a TCP socket to a remote endpoint
1993  * @work: RPC transport to connect
1994  *
1995  * Invoked by a work queue tasklet.
1996  */
1997 static void xs_tcp_connect_worker6(struct work_struct *work)
1998 {
1999 	struct sock_xprt *transport =
2000 		container_of(work, struct sock_xprt, connect_worker.work);
2001 	struct rpc_xprt *xprt = &transport->xprt;
2002 
2003 	xs_tcp_setup_socket(xprt, transport, xs_create_tcp_sock6);
2004 }
2005 
2006 /**
2007  * xs_connect - connect a socket to a remote endpoint
2008  * @task: address of RPC task that manages state of connect request
2009  *
2010  * TCP: If the remote end dropped the connection, delay reconnecting.
2011  *
2012  * UDP socket connects are synchronous, but we use a work queue anyway
2013  * to guarantee that even unprivileged user processes can set up a
2014  * socket on a privileged port.
2015  *
2016  * If a UDP socket connect fails, the delay behavior here prevents
2017  * retry floods (hard mounts).
2018  */
2019 static void xs_connect(struct rpc_task *task)
2020 {
2021 	struct rpc_xprt *xprt = task->tk_xprt;
2022 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2023 
2024 	if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) {
2025 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2026 				"seconds\n",
2027 				xprt, xprt->reestablish_timeout / HZ);
2028 		queue_delayed_work(rpciod_workqueue,
2029 				   &transport->connect_worker,
2030 				   xprt->reestablish_timeout);
2031 		xprt->reestablish_timeout <<= 1;
2032 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2033 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2034 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
2035 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
2036 	} else {
2037 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2038 		queue_delayed_work(rpciod_workqueue,
2039 				   &transport->connect_worker, 0);
2040 	}
2041 }
2042 
2043 /**
2044  * xs_udp_print_stats - display UDP socket-specifc stats
2045  * @xprt: rpc_xprt struct containing statistics
2046  * @seq: output file
2047  *
2048  */
2049 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2050 {
2051 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2052 
2053 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %Lu %Lu\n",
2054 			transport->srcport,
2055 			xprt->stat.bind_count,
2056 			xprt->stat.sends,
2057 			xprt->stat.recvs,
2058 			xprt->stat.bad_xids,
2059 			xprt->stat.req_u,
2060 			xprt->stat.bklog_u);
2061 }
2062 
2063 /**
2064  * xs_tcp_print_stats - display TCP socket-specifc stats
2065  * @xprt: rpc_xprt struct containing statistics
2066  * @seq: output file
2067  *
2068  */
2069 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2070 {
2071 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2072 	long idle_time = 0;
2073 
2074 	if (xprt_connected(xprt))
2075 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2076 
2077 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu %Lu %Lu\n",
2078 			transport->srcport,
2079 			xprt->stat.bind_count,
2080 			xprt->stat.connect_count,
2081 			xprt->stat.connect_time,
2082 			idle_time,
2083 			xprt->stat.sends,
2084 			xprt->stat.recvs,
2085 			xprt->stat.bad_xids,
2086 			xprt->stat.req_u,
2087 			xprt->stat.bklog_u);
2088 }
2089 
2090 /*
2091  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2092  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2093  * to use the server side send routines.
2094  */
2095 static void *bc_malloc(struct rpc_task *task, size_t size)
2096 {
2097 	struct page *page;
2098 	struct rpc_buffer *buf;
2099 
2100 	BUG_ON(size > PAGE_SIZE - sizeof(struct rpc_buffer));
2101 	page = alloc_page(GFP_KERNEL);
2102 
2103 	if (!page)
2104 		return NULL;
2105 
2106 	buf = page_address(page);
2107 	buf->len = PAGE_SIZE;
2108 
2109 	return buf->data;
2110 }
2111 
2112 /*
2113  * Free the space allocated in the bc_alloc routine
2114  */
2115 static void bc_free(void *buffer)
2116 {
2117 	struct rpc_buffer *buf;
2118 
2119 	if (!buffer)
2120 		return;
2121 
2122 	buf = container_of(buffer, struct rpc_buffer, data);
2123 	free_page((unsigned long)buf);
2124 }
2125 
2126 /*
2127  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2128  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2129  */
2130 static int bc_sendto(struct rpc_rqst *req)
2131 {
2132 	int len;
2133 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2134 	struct rpc_xprt *xprt = req->rq_xprt;
2135 	struct sock_xprt *transport =
2136 				container_of(xprt, struct sock_xprt, xprt);
2137 	struct socket *sock = transport->sock;
2138 	unsigned long headoff;
2139 	unsigned long tailoff;
2140 
2141 	/*
2142 	 * Set up the rpc header and record marker stuff
2143 	 */
2144 	xs_encode_tcp_record_marker(xbufp);
2145 
2146 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2147 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2148 	len = svc_send_common(sock, xbufp,
2149 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2150 			      xbufp->tail[0].iov_base, tailoff);
2151 
2152 	if (len != xbufp->len) {
2153 		printk(KERN_NOTICE "Error sending entire callback!\n");
2154 		len = -EAGAIN;
2155 	}
2156 
2157 	return len;
2158 }
2159 
2160 /*
2161  * The send routine. Borrows from svc_send
2162  */
2163 static int bc_send_request(struct rpc_task *task)
2164 {
2165 	struct rpc_rqst *req = task->tk_rqstp;
2166 	struct svc_xprt	*xprt;
2167 	struct svc_sock         *svsk;
2168 	u32                     len;
2169 
2170 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2171 	/*
2172 	 * Get the server socket associated with this callback xprt
2173 	 */
2174 	xprt = req->rq_xprt->bc_xprt;
2175 	svsk = container_of(xprt, struct svc_sock, sk_xprt);
2176 
2177 	/*
2178 	 * Grab the mutex to serialize data as the connection is shared
2179 	 * with the fore channel
2180 	 */
2181 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2182 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2183 		if (!mutex_trylock(&xprt->xpt_mutex))
2184 			return -EAGAIN;
2185 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2186 	}
2187 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2188 		len = -ENOTCONN;
2189 	else
2190 		len = bc_sendto(req);
2191 	mutex_unlock(&xprt->xpt_mutex);
2192 
2193 	if (len > 0)
2194 		len = 0;
2195 
2196 	return len;
2197 }
2198 
2199 /*
2200  * The close routine. Since this is client initiated, we do nothing
2201  */
2202 
2203 static void bc_close(struct rpc_xprt *xprt)
2204 {
2205 }
2206 
2207 /*
2208  * The xprt destroy routine. Again, because this connection is client
2209  * initiated, we do nothing
2210  */
2211 
2212 static void bc_destroy(struct rpc_xprt *xprt)
2213 {
2214 }
2215 
2216 static struct rpc_xprt_ops xs_udp_ops = {
2217 	.set_buffer_size	= xs_udp_set_buffer_size,
2218 	.reserve_xprt		= xprt_reserve_xprt_cong,
2219 	.release_xprt		= xprt_release_xprt_cong,
2220 	.rpcbind		= rpcb_getport_async,
2221 	.set_port		= xs_set_port,
2222 	.connect		= xs_connect,
2223 	.buf_alloc		= rpc_malloc,
2224 	.buf_free		= rpc_free,
2225 	.send_request		= xs_udp_send_request,
2226 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2227 	.timer			= xs_udp_timer,
2228 	.release_request	= xprt_release_rqst_cong,
2229 	.close			= xs_close,
2230 	.destroy		= xs_destroy,
2231 	.print_stats		= xs_udp_print_stats,
2232 };
2233 
2234 static struct rpc_xprt_ops xs_tcp_ops = {
2235 	.reserve_xprt		= xprt_reserve_xprt,
2236 	.release_xprt		= xs_tcp_release_xprt,
2237 	.rpcbind		= rpcb_getport_async,
2238 	.set_port		= xs_set_port,
2239 	.connect		= xs_connect,
2240 	.buf_alloc		= rpc_malloc,
2241 	.buf_free		= rpc_free,
2242 	.send_request		= xs_tcp_send_request,
2243 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2244 	.close			= xs_tcp_close,
2245 	.destroy		= xs_destroy,
2246 	.print_stats		= xs_tcp_print_stats,
2247 };
2248 
2249 /*
2250  * The rpc_xprt_ops for the server backchannel
2251  */
2252 
2253 static struct rpc_xprt_ops bc_tcp_ops = {
2254 	.reserve_xprt		= xprt_reserve_xprt,
2255 	.release_xprt		= xprt_release_xprt,
2256 	.buf_alloc		= bc_malloc,
2257 	.buf_free		= bc_free,
2258 	.send_request		= bc_send_request,
2259 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2260 	.close			= bc_close,
2261 	.destroy		= bc_destroy,
2262 	.print_stats		= xs_tcp_print_stats,
2263 };
2264 
2265 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2266 				      unsigned int slot_table_size)
2267 {
2268 	struct rpc_xprt *xprt;
2269 	struct sock_xprt *new;
2270 
2271 	if (args->addrlen > sizeof(xprt->addr)) {
2272 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2273 		return ERR_PTR(-EBADF);
2274 	}
2275 
2276 	new = kzalloc(sizeof(*new), GFP_KERNEL);
2277 	if (new == NULL) {
2278 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2279 				"rpc_xprt\n");
2280 		return ERR_PTR(-ENOMEM);
2281 	}
2282 	xprt = &new->xprt;
2283 
2284 	xprt->max_reqs = slot_table_size;
2285 	xprt->slot = kcalloc(xprt->max_reqs, sizeof(struct rpc_rqst), GFP_KERNEL);
2286 	if (xprt->slot == NULL) {
2287 		kfree(xprt);
2288 		dprintk("RPC:       xs_setup_xprt: couldn't allocate slot "
2289 				"table\n");
2290 		return ERR_PTR(-ENOMEM);
2291 	}
2292 
2293 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2294 	xprt->addrlen = args->addrlen;
2295 	if (args->srcaddr)
2296 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2297 
2298 	return xprt;
2299 }
2300 
2301 static const struct rpc_timeout xs_udp_default_timeout = {
2302 	.to_initval = 5 * HZ,
2303 	.to_maxval = 30 * HZ,
2304 	.to_increment = 5 * HZ,
2305 	.to_retries = 5,
2306 };
2307 
2308 /**
2309  * xs_setup_udp - Set up transport to use a UDP socket
2310  * @args: rpc transport creation arguments
2311  *
2312  */
2313 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2314 {
2315 	struct sockaddr *addr = args->dstaddr;
2316 	struct rpc_xprt *xprt;
2317 	struct sock_xprt *transport;
2318 	struct rpc_xprt *ret;
2319 
2320 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries);
2321 	if (IS_ERR(xprt))
2322 		return xprt;
2323 	transport = container_of(xprt, struct sock_xprt, xprt);
2324 
2325 	xprt->prot = IPPROTO_UDP;
2326 	xprt->tsh_size = 0;
2327 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2328 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2329 
2330 	xprt->bind_timeout = XS_BIND_TO;
2331 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2332 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2333 
2334 	xprt->ops = &xs_udp_ops;
2335 
2336 	xprt->timeout = &xs_udp_default_timeout;
2337 
2338 	switch (addr->sa_family) {
2339 	case AF_INET:
2340 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2341 			xprt_set_bound(xprt);
2342 
2343 		INIT_DELAYED_WORK(&transport->connect_worker,
2344 					xs_udp_connect_worker4);
2345 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2346 		break;
2347 	case AF_INET6:
2348 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2349 			xprt_set_bound(xprt);
2350 
2351 		INIT_DELAYED_WORK(&transport->connect_worker,
2352 					xs_udp_connect_worker6);
2353 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2354 		break;
2355 	default:
2356 		ret = ERR_PTR(-EAFNOSUPPORT);
2357 		goto out_err;
2358 	}
2359 
2360 	if (xprt_bound(xprt))
2361 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2362 				xprt->address_strings[RPC_DISPLAY_ADDR],
2363 				xprt->address_strings[RPC_DISPLAY_PORT],
2364 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2365 	else
2366 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2367 				xprt->address_strings[RPC_DISPLAY_ADDR],
2368 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2369 
2370 	if (try_module_get(THIS_MODULE))
2371 		return xprt;
2372 	ret = ERR_PTR(-EINVAL);
2373 out_err:
2374 	kfree(xprt->slot);
2375 	kfree(xprt);
2376 	return ret;
2377 }
2378 
2379 static const struct rpc_timeout xs_tcp_default_timeout = {
2380 	.to_initval = 60 * HZ,
2381 	.to_maxval = 60 * HZ,
2382 	.to_retries = 2,
2383 };
2384 
2385 /**
2386  * xs_setup_tcp - Set up transport to use a TCP socket
2387  * @args: rpc transport creation arguments
2388  *
2389  */
2390 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2391 {
2392 	struct sockaddr *addr = args->dstaddr;
2393 	struct rpc_xprt *xprt;
2394 	struct sock_xprt *transport;
2395 	struct rpc_xprt *ret;
2396 
2397 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
2398 	if (IS_ERR(xprt))
2399 		return xprt;
2400 	transport = container_of(xprt, struct sock_xprt, xprt);
2401 
2402 	xprt->prot = IPPROTO_TCP;
2403 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2404 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2405 
2406 	xprt->bind_timeout = XS_BIND_TO;
2407 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2408 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2409 
2410 	xprt->ops = &xs_tcp_ops;
2411 	xprt->timeout = &xs_tcp_default_timeout;
2412 
2413 	switch (addr->sa_family) {
2414 	case AF_INET:
2415 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2416 			xprt_set_bound(xprt);
2417 
2418 		INIT_DELAYED_WORK(&transport->connect_worker,
2419 					xs_tcp_connect_worker4);
2420 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
2421 		break;
2422 	case AF_INET6:
2423 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2424 			xprt_set_bound(xprt);
2425 
2426 		INIT_DELAYED_WORK(&transport->connect_worker,
2427 					xs_tcp_connect_worker6);
2428 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
2429 		break;
2430 	default:
2431 		ret = ERR_PTR(-EAFNOSUPPORT);
2432 		goto out_err;
2433 	}
2434 
2435 	if (xprt_bound(xprt))
2436 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2437 				xprt->address_strings[RPC_DISPLAY_ADDR],
2438 				xprt->address_strings[RPC_DISPLAY_PORT],
2439 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2440 	else
2441 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2442 				xprt->address_strings[RPC_DISPLAY_ADDR],
2443 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2444 
2445 
2446 	if (try_module_get(THIS_MODULE))
2447 		return xprt;
2448 	ret = ERR_PTR(-EINVAL);
2449 out_err:
2450 	kfree(xprt->slot);
2451 	kfree(xprt);
2452 	return ret;
2453 }
2454 
2455 /**
2456  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
2457  * @args: rpc transport creation arguments
2458  *
2459  */
2460 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
2461 {
2462 	struct sockaddr *addr = args->dstaddr;
2463 	struct rpc_xprt *xprt;
2464 	struct sock_xprt *transport;
2465 	struct svc_sock *bc_sock;
2466 	struct rpc_xprt *ret;
2467 
2468 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
2469 	if (IS_ERR(xprt))
2470 		return xprt;
2471 	transport = container_of(xprt, struct sock_xprt, xprt);
2472 
2473 	xprt->prot = IPPROTO_TCP;
2474 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2475 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2476 	xprt->timeout = &xs_tcp_default_timeout;
2477 
2478 	/* backchannel */
2479 	xprt_set_bound(xprt);
2480 	xprt->bind_timeout = 0;
2481 	xprt->reestablish_timeout = 0;
2482 	xprt->idle_timeout = 0;
2483 
2484 	/*
2485 	 * The backchannel uses the same socket connection as the
2486 	 * forechannel
2487 	 */
2488 	xprt->bc_xprt = args->bc_xprt;
2489 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
2490 	bc_sock->sk_bc_xprt = xprt;
2491 	transport->sock = bc_sock->sk_sock;
2492 	transport->inet = bc_sock->sk_sk;
2493 
2494 	xprt->ops = &bc_tcp_ops;
2495 
2496 	switch (addr->sa_family) {
2497 	case AF_INET:
2498 		xs_format_peer_addresses(xprt, "tcp",
2499 					 RPCBIND_NETID_TCP);
2500 		break;
2501 	case AF_INET6:
2502 		xs_format_peer_addresses(xprt, "tcp",
2503 				   RPCBIND_NETID_TCP6);
2504 		break;
2505 	default:
2506 		ret = ERR_PTR(-EAFNOSUPPORT);
2507 		goto out_err;
2508 	}
2509 
2510 	if (xprt_bound(xprt))
2511 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2512 				xprt->address_strings[RPC_DISPLAY_ADDR],
2513 				xprt->address_strings[RPC_DISPLAY_PORT],
2514 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2515 	else
2516 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2517 				xprt->address_strings[RPC_DISPLAY_ADDR],
2518 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2519 
2520 	/*
2521 	 * Since we don't want connections for the backchannel, we set
2522 	 * the xprt status to connected
2523 	 */
2524 	xprt_set_connected(xprt);
2525 
2526 
2527 	if (try_module_get(THIS_MODULE))
2528 		return xprt;
2529 	ret = ERR_PTR(-EINVAL);
2530 out_err:
2531 	kfree(xprt->slot);
2532 	kfree(xprt);
2533 	return ret;
2534 }
2535 
2536 static struct xprt_class	xs_udp_transport = {
2537 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
2538 	.name		= "udp",
2539 	.owner		= THIS_MODULE,
2540 	.ident		= XPRT_TRANSPORT_UDP,
2541 	.setup		= xs_setup_udp,
2542 };
2543 
2544 static struct xprt_class	xs_tcp_transport = {
2545 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
2546 	.name		= "tcp",
2547 	.owner		= THIS_MODULE,
2548 	.ident		= XPRT_TRANSPORT_TCP,
2549 	.setup		= xs_setup_tcp,
2550 };
2551 
2552 static struct xprt_class	xs_bc_tcp_transport = {
2553 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
2554 	.name		= "tcp NFSv4.1 backchannel",
2555 	.owner		= THIS_MODULE,
2556 	.ident		= XPRT_TRANSPORT_BC_TCP,
2557 	.setup		= xs_setup_bc_tcp,
2558 };
2559 
2560 /**
2561  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
2562  *
2563  */
2564 int init_socket_xprt(void)
2565 {
2566 #ifdef RPC_DEBUG
2567 	if (!sunrpc_table_header)
2568 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
2569 #endif
2570 
2571 	xprt_register_transport(&xs_udp_transport);
2572 	xprt_register_transport(&xs_tcp_transport);
2573 	xprt_register_transport(&xs_bc_tcp_transport);
2574 
2575 	return 0;
2576 }
2577 
2578 /**
2579  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
2580  *
2581  */
2582 void cleanup_socket_xprt(void)
2583 {
2584 #ifdef RPC_DEBUG
2585 	if (sunrpc_table_header) {
2586 		unregister_sysctl_table(sunrpc_table_header);
2587 		sunrpc_table_header = NULL;
2588 	}
2589 #endif
2590 
2591 	xprt_unregister_transport(&xs_udp_transport);
2592 	xprt_unregister_transport(&xs_tcp_transport);
2593 	xprt_unregister_transport(&xs_bc_tcp_transport);
2594 }
2595 
2596 static int param_set_uint_minmax(const char *val,
2597 		const struct kernel_param *kp,
2598 		unsigned int min, unsigned int max)
2599 {
2600 	unsigned long num;
2601 	int ret;
2602 
2603 	if (!val)
2604 		return -EINVAL;
2605 	ret = strict_strtoul(val, 0, &num);
2606 	if (ret == -EINVAL || num < min || num > max)
2607 		return -EINVAL;
2608 	*((unsigned int *)kp->arg) = num;
2609 	return 0;
2610 }
2611 
2612 static int param_set_portnr(const char *val, const struct kernel_param *kp)
2613 {
2614 	return param_set_uint_minmax(val, kp,
2615 			RPC_MIN_RESVPORT,
2616 			RPC_MAX_RESVPORT);
2617 }
2618 
2619 static struct kernel_param_ops param_ops_portnr = {
2620 	.set = param_set_portnr,
2621 	.get = param_get_uint,
2622 };
2623 
2624 #define param_check_portnr(name, p) \
2625 	__param_check(name, p, unsigned int);
2626 
2627 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
2628 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
2629 
2630 static int param_set_slot_table_size(const char *val,
2631 				     const struct kernel_param *kp)
2632 {
2633 	return param_set_uint_minmax(val, kp,
2634 			RPC_MIN_SLOT_TABLE,
2635 			RPC_MAX_SLOT_TABLE);
2636 }
2637 
2638 static struct kernel_param_ops param_ops_slot_table_size = {
2639 	.set = param_set_slot_table_size,
2640 	.get = param_get_uint,
2641 };
2642 
2643 #define param_check_slot_table_size(name, p) \
2644 	__param_check(name, p, unsigned int);
2645 
2646 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
2647 		   slot_table_size, 0644);
2648 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
2649 		   slot_table_size, 0644);
2650 
2651