xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision 97da55fc)
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/string.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/capability.h>
26 #include <linux/pagemap.h>
27 #include <linux/errno.h>
28 #include <linux/socket.h>
29 #include <linux/in.h>
30 #include <linux/net.h>
31 #include <linux/mm.h>
32 #include <linux/un.h>
33 #include <linux/udp.h>
34 #include <linux/tcp.h>
35 #include <linux/sunrpc/clnt.h>
36 #include <linux/sunrpc/addr.h>
37 #include <linux/sunrpc/sched.h>
38 #include <linux/sunrpc/svcsock.h>
39 #include <linux/sunrpc/xprtsock.h>
40 #include <linux/file.h>
41 #ifdef CONFIG_SUNRPC_BACKCHANNEL
42 #include <linux/sunrpc/bc_xprt.h>
43 #endif
44 
45 #include <net/sock.h>
46 #include <net/checksum.h>
47 #include <net/udp.h>
48 #include <net/tcp.h>
49 
50 #include "sunrpc.h"
51 
52 static void xs_close(struct rpc_xprt *xprt);
53 
54 /*
55  * xprtsock tunables
56  */
57 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
58 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
59 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
60 
61 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
62 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
63 
64 #define XS_TCP_LINGER_TO	(15U * HZ)
65 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
66 
67 /*
68  * We can register our own files under /proc/sys/sunrpc by
69  * calling register_sysctl_table() again.  The files in that
70  * directory become the union of all files registered there.
71  *
72  * We simply need to make sure that we don't collide with
73  * someone else's file names!
74  */
75 
76 #ifdef RPC_DEBUG
77 
78 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
79 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
80 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
81 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
82 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
83 
84 static struct ctl_table_header *sunrpc_table_header;
85 
86 /*
87  * FIXME: changing the UDP slot table size should also resize the UDP
88  *        socket buffers for existing UDP transports
89  */
90 static ctl_table xs_tunables_table[] = {
91 	{
92 		.procname	= "udp_slot_table_entries",
93 		.data		= &xprt_udp_slot_table_entries,
94 		.maxlen		= sizeof(unsigned int),
95 		.mode		= 0644,
96 		.proc_handler	= proc_dointvec_minmax,
97 		.extra1		= &min_slot_table_size,
98 		.extra2		= &max_slot_table_size
99 	},
100 	{
101 		.procname	= "tcp_slot_table_entries",
102 		.data		= &xprt_tcp_slot_table_entries,
103 		.maxlen		= sizeof(unsigned int),
104 		.mode		= 0644,
105 		.proc_handler	= proc_dointvec_minmax,
106 		.extra1		= &min_slot_table_size,
107 		.extra2		= &max_slot_table_size
108 	},
109 	{
110 		.procname	= "tcp_max_slot_table_entries",
111 		.data		= &xprt_max_tcp_slot_table_entries,
112 		.maxlen		= sizeof(unsigned int),
113 		.mode		= 0644,
114 		.proc_handler	= proc_dointvec_minmax,
115 		.extra1		= &min_slot_table_size,
116 		.extra2		= &max_tcp_slot_table_limit
117 	},
118 	{
119 		.procname	= "min_resvport",
120 		.data		= &xprt_min_resvport,
121 		.maxlen		= sizeof(unsigned int),
122 		.mode		= 0644,
123 		.proc_handler	= proc_dointvec_minmax,
124 		.extra1		= &xprt_min_resvport_limit,
125 		.extra2		= &xprt_max_resvport_limit
126 	},
127 	{
128 		.procname	= "max_resvport",
129 		.data		= &xprt_max_resvport,
130 		.maxlen		= sizeof(unsigned int),
131 		.mode		= 0644,
132 		.proc_handler	= proc_dointvec_minmax,
133 		.extra1		= &xprt_min_resvport_limit,
134 		.extra2		= &xprt_max_resvport_limit
135 	},
136 	{
137 		.procname	= "tcp_fin_timeout",
138 		.data		= &xs_tcp_fin_timeout,
139 		.maxlen		= sizeof(xs_tcp_fin_timeout),
140 		.mode		= 0644,
141 		.proc_handler	= proc_dointvec_jiffies,
142 	},
143 	{ },
144 };
145 
146 static ctl_table sunrpc_table[] = {
147 	{
148 		.procname	= "sunrpc",
149 		.mode		= 0555,
150 		.child		= xs_tunables_table
151 	},
152 	{ },
153 };
154 
155 #endif
156 
157 /*
158  * Wait duration for a reply from the RPC portmapper.
159  */
160 #define XS_BIND_TO		(60U * HZ)
161 
162 /*
163  * Delay if a UDP socket connect error occurs.  This is most likely some
164  * kind of resource problem on the local host.
165  */
166 #define XS_UDP_REEST_TO		(2U * HZ)
167 
168 /*
169  * The reestablish timeout allows clients to delay for a bit before attempting
170  * to reconnect to a server that just dropped our connection.
171  *
172  * We implement an exponential backoff when trying to reestablish a TCP
173  * transport connection with the server.  Some servers like to drop a TCP
174  * connection when they are overworked, so we start with a short timeout and
175  * increase over time if the server is down or not responding.
176  */
177 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
178 #define XS_TCP_MAX_REEST_TO	(5U * 60 * HZ)
179 
180 /*
181  * TCP idle timeout; client drops the transport socket if it is idle
182  * for this long.  Note that we also timeout UDP sockets to prevent
183  * holding port numbers when there is no RPC traffic.
184  */
185 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
186 
187 #ifdef RPC_DEBUG
188 # undef  RPC_DEBUG_DATA
189 # define RPCDBG_FACILITY	RPCDBG_TRANS
190 #endif
191 
192 #ifdef RPC_DEBUG_DATA
193 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
194 {
195 	u8 *buf = (u8 *) packet;
196 	int j;
197 
198 	dprintk("RPC:       %s\n", msg);
199 	for (j = 0; j < count && j < 128; j += 4) {
200 		if (!(j & 31)) {
201 			if (j)
202 				dprintk("\n");
203 			dprintk("0x%04x ", j);
204 		}
205 		dprintk("%02x%02x%02x%02x ",
206 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
207 	}
208 	dprintk("\n");
209 }
210 #else
211 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
212 {
213 	/* NOP */
214 }
215 #endif
216 
217 struct sock_xprt {
218 	struct rpc_xprt		xprt;
219 
220 	/*
221 	 * Network layer
222 	 */
223 	struct socket *		sock;
224 	struct sock *		inet;
225 
226 	/*
227 	 * State of TCP reply receive
228 	 */
229 	__be32			tcp_fraghdr,
230 				tcp_xid,
231 				tcp_calldir;
232 
233 	u32			tcp_offset,
234 				tcp_reclen;
235 
236 	unsigned long		tcp_copied,
237 				tcp_flags;
238 
239 	/*
240 	 * Connection of transports
241 	 */
242 	struct delayed_work	connect_worker;
243 	struct sockaddr_storage	srcaddr;
244 	unsigned short		srcport;
245 
246 	/*
247 	 * UDP socket buffer size parameters
248 	 */
249 	size_t			rcvsize,
250 				sndsize;
251 
252 	/*
253 	 * Saved socket callback addresses
254 	 */
255 	void			(*old_data_ready)(struct sock *, int);
256 	void			(*old_state_change)(struct sock *);
257 	void			(*old_write_space)(struct sock *);
258 };
259 
260 /*
261  * TCP receive state flags
262  */
263 #define TCP_RCV_LAST_FRAG	(1UL << 0)
264 #define TCP_RCV_COPY_FRAGHDR	(1UL << 1)
265 #define TCP_RCV_COPY_XID	(1UL << 2)
266 #define TCP_RCV_COPY_DATA	(1UL << 3)
267 #define TCP_RCV_READ_CALLDIR	(1UL << 4)
268 #define TCP_RCV_COPY_CALLDIR	(1UL << 5)
269 
270 /*
271  * TCP RPC flags
272  */
273 #define TCP_RPC_REPLY		(1UL << 6)
274 
275 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
276 {
277 	return (struct sockaddr *) &xprt->addr;
278 }
279 
280 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
281 {
282 	return (struct sockaddr_un *) &xprt->addr;
283 }
284 
285 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
286 {
287 	return (struct sockaddr_in *) &xprt->addr;
288 }
289 
290 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
291 {
292 	return (struct sockaddr_in6 *) &xprt->addr;
293 }
294 
295 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
296 {
297 	struct sockaddr *sap = xs_addr(xprt);
298 	struct sockaddr_in6 *sin6;
299 	struct sockaddr_in *sin;
300 	struct sockaddr_un *sun;
301 	char buf[128];
302 
303 	switch (sap->sa_family) {
304 	case AF_LOCAL:
305 		sun = xs_addr_un(xprt);
306 		strlcpy(buf, sun->sun_path, sizeof(buf));
307 		xprt->address_strings[RPC_DISPLAY_ADDR] =
308 						kstrdup(buf, GFP_KERNEL);
309 		break;
310 	case AF_INET:
311 		(void)rpc_ntop(sap, buf, sizeof(buf));
312 		xprt->address_strings[RPC_DISPLAY_ADDR] =
313 						kstrdup(buf, GFP_KERNEL);
314 		sin = xs_addr_in(xprt);
315 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
316 		break;
317 	case AF_INET6:
318 		(void)rpc_ntop(sap, buf, sizeof(buf));
319 		xprt->address_strings[RPC_DISPLAY_ADDR] =
320 						kstrdup(buf, GFP_KERNEL);
321 		sin6 = xs_addr_in6(xprt);
322 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
323 		break;
324 	default:
325 		BUG();
326 	}
327 
328 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
329 }
330 
331 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
332 {
333 	struct sockaddr *sap = xs_addr(xprt);
334 	char buf[128];
335 
336 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
337 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
338 
339 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
340 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
341 }
342 
343 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
344 				     const char *protocol,
345 				     const char *netid)
346 {
347 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
348 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
349 	xs_format_common_peer_addresses(xprt);
350 	xs_format_common_peer_ports(xprt);
351 }
352 
353 static void xs_update_peer_port(struct rpc_xprt *xprt)
354 {
355 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
356 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
357 
358 	xs_format_common_peer_ports(xprt);
359 }
360 
361 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
362 {
363 	unsigned int i;
364 
365 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
366 		switch (i) {
367 		case RPC_DISPLAY_PROTO:
368 		case RPC_DISPLAY_NETID:
369 			continue;
370 		default:
371 			kfree(xprt->address_strings[i]);
372 		}
373 }
374 
375 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
376 
377 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
378 {
379 	struct msghdr msg = {
380 		.msg_name	= addr,
381 		.msg_namelen	= addrlen,
382 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
383 	};
384 	struct kvec iov = {
385 		.iov_base	= vec->iov_base + base,
386 		.iov_len	= vec->iov_len - base,
387 	};
388 
389 	if (iov.iov_len != 0)
390 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
391 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
392 }
393 
394 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more)
395 {
396 	struct page **ppage;
397 	unsigned int remainder;
398 	int err, sent = 0;
399 
400 	remainder = xdr->page_len - base;
401 	base += xdr->page_base;
402 	ppage = xdr->pages + (base >> PAGE_SHIFT);
403 	base &= ~PAGE_MASK;
404 	for(;;) {
405 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
406 		int flags = XS_SENDMSG_FLAGS;
407 
408 		remainder -= len;
409 		if (remainder != 0 || more)
410 			flags |= MSG_MORE;
411 		err = sock->ops->sendpage(sock, *ppage, base, len, flags);
412 		if (remainder == 0 || err != len)
413 			break;
414 		sent += err;
415 		ppage++;
416 		base = 0;
417 	}
418 	if (sent == 0)
419 		return err;
420 	if (err > 0)
421 		sent += err;
422 	return sent;
423 }
424 
425 /**
426  * xs_sendpages - write pages directly to a socket
427  * @sock: socket to send on
428  * @addr: UDP only -- address of destination
429  * @addrlen: UDP only -- length of destination address
430  * @xdr: buffer containing this request
431  * @base: starting position in the buffer
432  *
433  */
434 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
435 {
436 	unsigned int remainder = xdr->len - base;
437 	int err, sent = 0;
438 
439 	if (unlikely(!sock))
440 		return -ENOTSOCK;
441 
442 	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
443 	if (base != 0) {
444 		addr = NULL;
445 		addrlen = 0;
446 	}
447 
448 	if (base < xdr->head[0].iov_len || addr != NULL) {
449 		unsigned int len = xdr->head[0].iov_len - base;
450 		remainder -= len;
451 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
452 		if (remainder == 0 || err != len)
453 			goto out;
454 		sent += err;
455 		base = 0;
456 	} else
457 		base -= xdr->head[0].iov_len;
458 
459 	if (base < xdr->page_len) {
460 		unsigned int len = xdr->page_len - base;
461 		remainder -= len;
462 		err = xs_send_pagedata(sock, xdr, base, remainder != 0);
463 		if (remainder == 0 || err != len)
464 			goto out;
465 		sent += err;
466 		base = 0;
467 	} else
468 		base -= xdr->page_len;
469 
470 	if (base >= xdr->tail[0].iov_len)
471 		return sent;
472 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
473 out:
474 	if (sent == 0)
475 		return err;
476 	if (err > 0)
477 		sent += err;
478 	return sent;
479 }
480 
481 static void xs_nospace_callback(struct rpc_task *task)
482 {
483 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
484 
485 	transport->inet->sk_write_pending--;
486 	clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
487 }
488 
489 /**
490  * xs_nospace - place task on wait queue if transmit was incomplete
491  * @task: task to put to sleep
492  *
493  */
494 static int xs_nospace(struct rpc_task *task)
495 {
496 	struct rpc_rqst *req = task->tk_rqstp;
497 	struct rpc_xprt *xprt = req->rq_xprt;
498 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
499 	int ret = -EAGAIN;
500 
501 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
502 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
503 			req->rq_slen);
504 
505 	/* Protect against races with write_space */
506 	spin_lock_bh(&xprt->transport_lock);
507 
508 	/* Don't race with disconnect */
509 	if (xprt_connected(xprt)) {
510 		if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
511 			/*
512 			 * Notify TCP that we're limited by the application
513 			 * window size
514 			 */
515 			set_bit(SOCK_NOSPACE, &transport->sock->flags);
516 			transport->inet->sk_write_pending++;
517 			/* ...and wait for more buffer space */
518 			xprt_wait_for_buffer_space(task, xs_nospace_callback);
519 		}
520 	} else {
521 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
522 		ret = -ENOTCONN;
523 	}
524 
525 	spin_unlock_bh(&xprt->transport_lock);
526 	return ret;
527 }
528 
529 /*
530  * Construct a stream transport record marker in @buf.
531  */
532 static inline void xs_encode_stream_record_marker(struct xdr_buf *buf)
533 {
534 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
535 	rpc_fraghdr *base = buf->head[0].iov_base;
536 	*base = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen);
537 }
538 
539 /**
540  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
541  * @task: RPC task that manages the state of an RPC request
542  *
543  * Return values:
544  *        0:	The request has been sent
545  *   EAGAIN:	The socket was blocked, please call again later to
546  *		complete the request
547  * ENOTCONN:	Caller needs to invoke connect logic then call again
548  *    other:	Some other error occured, the request was not sent
549  */
550 static int xs_local_send_request(struct rpc_task *task)
551 {
552 	struct rpc_rqst *req = task->tk_rqstp;
553 	struct rpc_xprt *xprt = req->rq_xprt;
554 	struct sock_xprt *transport =
555 				container_of(xprt, struct sock_xprt, xprt);
556 	struct xdr_buf *xdr = &req->rq_snd_buf;
557 	int status;
558 
559 	xs_encode_stream_record_marker(&req->rq_snd_buf);
560 
561 	xs_pktdump("packet data:",
562 			req->rq_svec->iov_base, req->rq_svec->iov_len);
563 
564 	status = xs_sendpages(transport->sock, NULL, 0,
565 						xdr, req->rq_bytes_sent);
566 	dprintk("RPC:       %s(%u) = %d\n",
567 			__func__, xdr->len - req->rq_bytes_sent, status);
568 	if (likely(status >= 0)) {
569 		req->rq_bytes_sent += status;
570 		req->rq_xmit_bytes_sent += status;
571 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
572 			req->rq_bytes_sent = 0;
573 			return 0;
574 		}
575 		status = -EAGAIN;
576 	}
577 
578 	switch (status) {
579 	case -EAGAIN:
580 		status = xs_nospace(task);
581 		break;
582 	default:
583 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
584 			-status);
585 	case -EPIPE:
586 		xs_close(xprt);
587 		status = -ENOTCONN;
588 	}
589 
590 	return status;
591 }
592 
593 /**
594  * xs_udp_send_request - write an RPC request to a UDP socket
595  * @task: address of RPC task that manages the state of an RPC request
596  *
597  * Return values:
598  *        0:	The request has been sent
599  *   EAGAIN:	The socket was blocked, please call again later to
600  *		complete the request
601  * ENOTCONN:	Caller needs to invoke connect logic then call again
602  *    other:	Some other error occurred, the request was not sent
603  */
604 static int xs_udp_send_request(struct rpc_task *task)
605 {
606 	struct rpc_rqst *req = task->tk_rqstp;
607 	struct rpc_xprt *xprt = req->rq_xprt;
608 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
609 	struct xdr_buf *xdr = &req->rq_snd_buf;
610 	int status;
611 
612 	xs_pktdump("packet data:",
613 				req->rq_svec->iov_base,
614 				req->rq_svec->iov_len);
615 
616 	if (!xprt_bound(xprt))
617 		return -ENOTCONN;
618 	status = xs_sendpages(transport->sock,
619 			      xs_addr(xprt),
620 			      xprt->addrlen, xdr,
621 			      req->rq_bytes_sent);
622 
623 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
624 			xdr->len - req->rq_bytes_sent, status);
625 
626 	if (status >= 0) {
627 		req->rq_xmit_bytes_sent += status;
628 		if (status >= req->rq_slen)
629 			return 0;
630 		/* Still some bytes left; set up for a retry later. */
631 		status = -EAGAIN;
632 	}
633 
634 	switch (status) {
635 	case -ENOTSOCK:
636 		status = -ENOTCONN;
637 		/* Should we call xs_close() here? */
638 		break;
639 	case -EAGAIN:
640 		status = xs_nospace(task);
641 		break;
642 	default:
643 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
644 			-status);
645 	case -ENETUNREACH:
646 	case -EPIPE:
647 	case -ECONNREFUSED:
648 		/* When the server has died, an ICMP port unreachable message
649 		 * prompts ECONNREFUSED. */
650 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
651 	}
652 
653 	return status;
654 }
655 
656 /**
657  * xs_tcp_shutdown - gracefully shut down a TCP socket
658  * @xprt: transport
659  *
660  * Initiates a graceful shutdown of the TCP socket by calling the
661  * equivalent of shutdown(SHUT_WR);
662  */
663 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
664 {
665 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
666 	struct socket *sock = transport->sock;
667 
668 	if (sock != NULL)
669 		kernel_sock_shutdown(sock, SHUT_WR);
670 }
671 
672 /**
673  * xs_tcp_send_request - write an RPC request to a TCP socket
674  * @task: address of RPC task that manages the state of an RPC request
675  *
676  * Return values:
677  *        0:	The request has been sent
678  *   EAGAIN:	The socket was blocked, please call again later to
679  *		complete the request
680  * ENOTCONN:	Caller needs to invoke connect logic then call again
681  *    other:	Some other error occurred, the request was not sent
682  *
683  * XXX: In the case of soft timeouts, should we eventually give up
684  *	if sendmsg is not able to make progress?
685  */
686 static int xs_tcp_send_request(struct rpc_task *task)
687 {
688 	struct rpc_rqst *req = task->tk_rqstp;
689 	struct rpc_xprt *xprt = req->rq_xprt;
690 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
691 	struct xdr_buf *xdr = &req->rq_snd_buf;
692 	int status;
693 
694 	xs_encode_stream_record_marker(&req->rq_snd_buf);
695 
696 	xs_pktdump("packet data:",
697 				req->rq_svec->iov_base,
698 				req->rq_svec->iov_len);
699 
700 	/* Continue transmitting the packet/record. We must be careful
701 	 * to cope with writespace callbacks arriving _after_ we have
702 	 * called sendmsg(). */
703 	while (1) {
704 		status = xs_sendpages(transport->sock,
705 					NULL, 0, xdr, req->rq_bytes_sent);
706 
707 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
708 				xdr->len - req->rq_bytes_sent, status);
709 
710 		if (unlikely(status < 0))
711 			break;
712 
713 		/* If we've sent the entire packet, immediately
714 		 * reset the count of bytes sent. */
715 		req->rq_bytes_sent += status;
716 		req->rq_xmit_bytes_sent += status;
717 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
718 			req->rq_bytes_sent = 0;
719 			return 0;
720 		}
721 
722 		if (status != 0)
723 			continue;
724 		status = -EAGAIN;
725 		break;
726 	}
727 
728 	switch (status) {
729 	case -ENOTSOCK:
730 		status = -ENOTCONN;
731 		/* Should we call xs_close() here? */
732 		break;
733 	case -EAGAIN:
734 		status = xs_nospace(task);
735 		break;
736 	default:
737 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
738 			-status);
739 	case -ECONNRESET:
740 		xs_tcp_shutdown(xprt);
741 	case -ECONNREFUSED:
742 	case -ENOTCONN:
743 	case -EPIPE:
744 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
745 	}
746 
747 	return status;
748 }
749 
750 /**
751  * xs_tcp_release_xprt - clean up after a tcp transmission
752  * @xprt: transport
753  * @task: rpc task
754  *
755  * This cleans up if an error causes us to abort the transmission of a request.
756  * In this case, the socket may need to be reset in order to avoid confusing
757  * the server.
758  */
759 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
760 {
761 	struct rpc_rqst *req;
762 
763 	if (task != xprt->snd_task)
764 		return;
765 	if (task == NULL)
766 		goto out_release;
767 	req = task->tk_rqstp;
768 	if (req == NULL)
769 		goto out_release;
770 	if (req->rq_bytes_sent == 0)
771 		goto out_release;
772 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
773 		goto out_release;
774 	set_bit(XPRT_CLOSE_WAIT, &xprt->state);
775 out_release:
776 	xprt_release_xprt(xprt, task);
777 }
778 
779 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
780 {
781 	transport->old_data_ready = sk->sk_data_ready;
782 	transport->old_state_change = sk->sk_state_change;
783 	transport->old_write_space = sk->sk_write_space;
784 }
785 
786 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
787 {
788 	sk->sk_data_ready = transport->old_data_ready;
789 	sk->sk_state_change = transport->old_state_change;
790 	sk->sk_write_space = transport->old_write_space;
791 }
792 
793 static void xs_reset_transport(struct sock_xprt *transport)
794 {
795 	struct socket *sock = transport->sock;
796 	struct sock *sk = transport->inet;
797 
798 	if (sk == NULL)
799 		return;
800 
801 	transport->srcport = 0;
802 
803 	write_lock_bh(&sk->sk_callback_lock);
804 	transport->inet = NULL;
805 	transport->sock = NULL;
806 
807 	sk->sk_user_data = NULL;
808 
809 	xs_restore_old_callbacks(transport, sk);
810 	write_unlock_bh(&sk->sk_callback_lock);
811 
812 	sk->sk_no_check = 0;
813 
814 	sock_release(sock);
815 }
816 
817 /**
818  * xs_close - close a socket
819  * @xprt: transport
820  *
821  * This is used when all requests are complete; ie, no DRC state remains
822  * on the server we want to save.
823  *
824  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
825  * xs_reset_transport() zeroing the socket from underneath a writer.
826  */
827 static void xs_close(struct rpc_xprt *xprt)
828 {
829 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
830 
831 	dprintk("RPC:       xs_close xprt %p\n", xprt);
832 
833 	xs_reset_transport(transport);
834 	xprt->reestablish_timeout = 0;
835 
836 	smp_mb__before_clear_bit();
837 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
838 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
839 	clear_bit(XPRT_CLOSING, &xprt->state);
840 	smp_mb__after_clear_bit();
841 	xprt_disconnect_done(xprt);
842 }
843 
844 static void xs_tcp_close(struct rpc_xprt *xprt)
845 {
846 	if (test_and_clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state))
847 		xs_close(xprt);
848 	else
849 		xs_tcp_shutdown(xprt);
850 }
851 
852 static void xs_local_destroy(struct rpc_xprt *xprt)
853 {
854 	xs_close(xprt);
855 	xs_free_peer_addresses(xprt);
856 	xprt_free(xprt);
857 	module_put(THIS_MODULE);
858 }
859 
860 /**
861  * xs_destroy - prepare to shutdown a transport
862  * @xprt: doomed transport
863  *
864  */
865 static void xs_destroy(struct rpc_xprt *xprt)
866 {
867 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
868 
869 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
870 
871 	cancel_delayed_work_sync(&transport->connect_worker);
872 
873 	xs_local_destroy(xprt);
874 }
875 
876 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
877 {
878 	return (struct rpc_xprt *) sk->sk_user_data;
879 }
880 
881 static int xs_local_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
882 {
883 	struct xdr_skb_reader desc = {
884 		.skb		= skb,
885 		.offset		= sizeof(rpc_fraghdr),
886 		.count		= skb->len - sizeof(rpc_fraghdr),
887 	};
888 
889 	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
890 		return -1;
891 	if (desc.count)
892 		return -1;
893 	return 0;
894 }
895 
896 /**
897  * xs_local_data_ready - "data ready" callback for AF_LOCAL sockets
898  * @sk: socket with data to read
899  * @len: how much data to read
900  *
901  * Currently this assumes we can read the whole reply in a single gulp.
902  */
903 static void xs_local_data_ready(struct sock *sk, int len)
904 {
905 	struct rpc_task *task;
906 	struct rpc_xprt *xprt;
907 	struct rpc_rqst *rovr;
908 	struct sk_buff *skb;
909 	int err, repsize, copied;
910 	u32 _xid;
911 	__be32 *xp;
912 
913 	read_lock_bh(&sk->sk_callback_lock);
914 	dprintk("RPC:       %s...\n", __func__);
915 	xprt = xprt_from_sock(sk);
916 	if (xprt == NULL)
917 		goto out;
918 
919 	skb = skb_recv_datagram(sk, 0, 1, &err);
920 	if (skb == NULL)
921 		goto out;
922 
923 	repsize = skb->len - sizeof(rpc_fraghdr);
924 	if (repsize < 4) {
925 		dprintk("RPC:       impossible RPC reply size %d\n", repsize);
926 		goto dropit;
927 	}
928 
929 	/* Copy the XID from the skb... */
930 	xp = skb_header_pointer(skb, sizeof(rpc_fraghdr), sizeof(_xid), &_xid);
931 	if (xp == NULL)
932 		goto dropit;
933 
934 	/* Look up and lock the request corresponding to the given XID */
935 	spin_lock(&xprt->transport_lock);
936 	rovr = xprt_lookup_rqst(xprt, *xp);
937 	if (!rovr)
938 		goto out_unlock;
939 	task = rovr->rq_task;
940 
941 	copied = rovr->rq_private_buf.buflen;
942 	if (copied > repsize)
943 		copied = repsize;
944 
945 	if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) {
946 		dprintk("RPC:       sk_buff copy failed\n");
947 		goto out_unlock;
948 	}
949 
950 	xprt_complete_rqst(task, copied);
951 
952  out_unlock:
953 	spin_unlock(&xprt->transport_lock);
954  dropit:
955 	skb_free_datagram(sk, skb);
956  out:
957 	read_unlock_bh(&sk->sk_callback_lock);
958 }
959 
960 /**
961  * xs_udp_data_ready - "data ready" callback for UDP sockets
962  * @sk: socket with data to read
963  * @len: how much data to read
964  *
965  */
966 static void xs_udp_data_ready(struct sock *sk, int len)
967 {
968 	struct rpc_task *task;
969 	struct rpc_xprt *xprt;
970 	struct rpc_rqst *rovr;
971 	struct sk_buff *skb;
972 	int err, repsize, copied;
973 	u32 _xid;
974 	__be32 *xp;
975 
976 	read_lock_bh(&sk->sk_callback_lock);
977 	dprintk("RPC:       xs_udp_data_ready...\n");
978 	if (!(xprt = xprt_from_sock(sk)))
979 		goto out;
980 
981 	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
982 		goto out;
983 
984 	repsize = skb->len - sizeof(struct udphdr);
985 	if (repsize < 4) {
986 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
987 		goto dropit;
988 	}
989 
990 	/* Copy the XID from the skb... */
991 	xp = skb_header_pointer(skb, sizeof(struct udphdr),
992 				sizeof(_xid), &_xid);
993 	if (xp == NULL)
994 		goto dropit;
995 
996 	/* Look up and lock the request corresponding to the given XID */
997 	spin_lock(&xprt->transport_lock);
998 	rovr = xprt_lookup_rqst(xprt, *xp);
999 	if (!rovr)
1000 		goto out_unlock;
1001 	task = rovr->rq_task;
1002 
1003 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
1004 		copied = repsize;
1005 
1006 	/* Suck it into the iovec, verify checksum if not done by hw. */
1007 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1008 		UDPX_INC_STATS_BH(sk, UDP_MIB_INERRORS);
1009 		goto out_unlock;
1010 	}
1011 
1012 	UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
1013 
1014 	xprt_adjust_cwnd(xprt, task, copied);
1015 	xprt_complete_rqst(task, copied);
1016 
1017  out_unlock:
1018 	spin_unlock(&xprt->transport_lock);
1019  dropit:
1020 	skb_free_datagram(sk, skb);
1021  out:
1022 	read_unlock_bh(&sk->sk_callback_lock);
1023 }
1024 
1025 /*
1026  * Helper function to force a TCP close if the server is sending
1027  * junk and/or it has put us in CLOSE_WAIT
1028  */
1029 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1030 {
1031 	set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1032 	xprt_force_disconnect(xprt);
1033 }
1034 
1035 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
1036 {
1037 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1038 	size_t len, used;
1039 	char *p;
1040 
1041 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
1042 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
1043 	used = xdr_skb_read_bits(desc, p, len);
1044 	transport->tcp_offset += used;
1045 	if (used != len)
1046 		return;
1047 
1048 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
1049 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
1050 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
1051 	else
1052 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
1053 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
1054 
1055 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
1056 	transport->tcp_offset = 0;
1057 
1058 	/* Sanity check of the record length */
1059 	if (unlikely(transport->tcp_reclen < 8)) {
1060 		dprintk("RPC:       invalid TCP record fragment length\n");
1061 		xs_tcp_force_close(xprt);
1062 		return;
1063 	}
1064 	dprintk("RPC:       reading TCP record fragment of length %d\n",
1065 			transport->tcp_reclen);
1066 }
1067 
1068 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
1069 {
1070 	if (transport->tcp_offset == transport->tcp_reclen) {
1071 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
1072 		transport->tcp_offset = 0;
1073 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
1074 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1075 			transport->tcp_flags |= TCP_RCV_COPY_XID;
1076 			transport->tcp_copied = 0;
1077 		}
1078 	}
1079 }
1080 
1081 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1082 {
1083 	size_t len, used;
1084 	char *p;
1085 
1086 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
1087 	dprintk("RPC:       reading XID (%Zu bytes)\n", len);
1088 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
1089 	used = xdr_skb_read_bits(desc, p, len);
1090 	transport->tcp_offset += used;
1091 	if (used != len)
1092 		return;
1093 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
1094 	transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
1095 	transport->tcp_copied = 4;
1096 	dprintk("RPC:       reading %s XID %08x\n",
1097 			(transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
1098 							      : "request with",
1099 			ntohl(transport->tcp_xid));
1100 	xs_tcp_check_fraghdr(transport);
1101 }
1102 
1103 static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
1104 				       struct xdr_skb_reader *desc)
1105 {
1106 	size_t len, used;
1107 	u32 offset;
1108 	char *p;
1109 
1110 	/*
1111 	 * We want transport->tcp_offset to be 8 at the end of this routine
1112 	 * (4 bytes for the xid and 4 bytes for the call/reply flag).
1113 	 * When this function is called for the first time,
1114 	 * transport->tcp_offset is 4 (after having already read the xid).
1115 	 */
1116 	offset = transport->tcp_offset - sizeof(transport->tcp_xid);
1117 	len = sizeof(transport->tcp_calldir) - offset;
1118 	dprintk("RPC:       reading CALL/REPLY flag (%Zu bytes)\n", len);
1119 	p = ((char *) &transport->tcp_calldir) + offset;
1120 	used = xdr_skb_read_bits(desc, p, len);
1121 	transport->tcp_offset += used;
1122 	if (used != len)
1123 		return;
1124 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
1125 	/*
1126 	 * We don't yet have the XDR buffer, so we will write the calldir
1127 	 * out after we get the buffer from the 'struct rpc_rqst'
1128 	 */
1129 	switch (ntohl(transport->tcp_calldir)) {
1130 	case RPC_REPLY:
1131 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1132 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1133 		transport->tcp_flags |= TCP_RPC_REPLY;
1134 		break;
1135 	case RPC_CALL:
1136 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1137 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1138 		transport->tcp_flags &= ~TCP_RPC_REPLY;
1139 		break;
1140 	default:
1141 		dprintk("RPC:       invalid request message type\n");
1142 		xs_tcp_force_close(&transport->xprt);
1143 	}
1144 	xs_tcp_check_fraghdr(transport);
1145 }
1146 
1147 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
1148 				     struct xdr_skb_reader *desc,
1149 				     struct rpc_rqst *req)
1150 {
1151 	struct sock_xprt *transport =
1152 				container_of(xprt, struct sock_xprt, xprt);
1153 	struct xdr_buf *rcvbuf;
1154 	size_t len;
1155 	ssize_t r;
1156 
1157 	rcvbuf = &req->rq_private_buf;
1158 
1159 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
1160 		/*
1161 		 * Save the RPC direction in the XDR buffer
1162 		 */
1163 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
1164 			&transport->tcp_calldir,
1165 			sizeof(transport->tcp_calldir));
1166 		transport->tcp_copied += sizeof(transport->tcp_calldir);
1167 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
1168 	}
1169 
1170 	len = desc->count;
1171 	if (len > transport->tcp_reclen - transport->tcp_offset) {
1172 		struct xdr_skb_reader my_desc;
1173 
1174 		len = transport->tcp_reclen - transport->tcp_offset;
1175 		memcpy(&my_desc, desc, sizeof(my_desc));
1176 		my_desc.count = len;
1177 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1178 					  &my_desc, xdr_skb_read_bits);
1179 		desc->count -= r;
1180 		desc->offset += r;
1181 	} else
1182 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1183 					  desc, xdr_skb_read_bits);
1184 
1185 	if (r > 0) {
1186 		transport->tcp_copied += r;
1187 		transport->tcp_offset += r;
1188 	}
1189 	if (r != len) {
1190 		/* Error when copying to the receive buffer,
1191 		 * usually because we weren't able to allocate
1192 		 * additional buffer pages. All we can do now
1193 		 * is turn off TCP_RCV_COPY_DATA, so the request
1194 		 * will not receive any additional updates,
1195 		 * and time out.
1196 		 * Any remaining data from this record will
1197 		 * be discarded.
1198 		 */
1199 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1200 		dprintk("RPC:       XID %08x truncated request\n",
1201 				ntohl(transport->tcp_xid));
1202 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1203 				"tcp_offset = %u, tcp_reclen = %u\n",
1204 				xprt, transport->tcp_copied,
1205 				transport->tcp_offset, transport->tcp_reclen);
1206 		return;
1207 	}
1208 
1209 	dprintk("RPC:       XID %08x read %Zd bytes\n",
1210 			ntohl(transport->tcp_xid), r);
1211 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1212 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1213 			transport->tcp_offset, transport->tcp_reclen);
1214 
1215 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1216 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1217 	else if (transport->tcp_offset == transport->tcp_reclen) {
1218 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1219 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1220 	}
1221 }
1222 
1223 /*
1224  * Finds the request corresponding to the RPC xid and invokes the common
1225  * tcp read code to read the data.
1226  */
1227 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1228 				    struct xdr_skb_reader *desc)
1229 {
1230 	struct sock_xprt *transport =
1231 				container_of(xprt, struct sock_xprt, xprt);
1232 	struct rpc_rqst *req;
1233 
1234 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1235 
1236 	/* Find and lock the request corresponding to this xid */
1237 	spin_lock(&xprt->transport_lock);
1238 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1239 	if (!req) {
1240 		dprintk("RPC:       XID %08x request not found!\n",
1241 				ntohl(transport->tcp_xid));
1242 		spin_unlock(&xprt->transport_lock);
1243 		return -1;
1244 	}
1245 
1246 	xs_tcp_read_common(xprt, desc, req);
1247 
1248 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1249 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1250 
1251 	spin_unlock(&xprt->transport_lock);
1252 	return 0;
1253 }
1254 
1255 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1256 /*
1257  * Obtains an rpc_rqst previously allocated and invokes the common
1258  * tcp read code to read the data.  The result is placed in the callback
1259  * queue.
1260  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1261  * connection and return -1.
1262  */
1263 static inline int xs_tcp_read_callback(struct rpc_xprt *xprt,
1264 				       struct xdr_skb_reader *desc)
1265 {
1266 	struct sock_xprt *transport =
1267 				container_of(xprt, struct sock_xprt, xprt);
1268 	struct rpc_rqst *req;
1269 
1270 	req = xprt_alloc_bc_request(xprt);
1271 	if (req == NULL) {
1272 		printk(KERN_WARNING "Callback slot table overflowed\n");
1273 		xprt_force_disconnect(xprt);
1274 		return -1;
1275 	}
1276 
1277 	req->rq_xid = transport->tcp_xid;
1278 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1279 	xs_tcp_read_common(xprt, desc, req);
1280 
1281 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) {
1282 		struct svc_serv *bc_serv = xprt->bc_serv;
1283 
1284 		/*
1285 		 * Add callback request to callback list.  The callback
1286 		 * service sleeps on the sv_cb_waitq waiting for new
1287 		 * requests.  Wake it up after adding enqueing the
1288 		 * request.
1289 		 */
1290 		dprintk("RPC:       add callback request to list\n");
1291 		spin_lock(&bc_serv->sv_cb_lock);
1292 		list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
1293 		spin_unlock(&bc_serv->sv_cb_lock);
1294 		wake_up(&bc_serv->sv_cb_waitq);
1295 	}
1296 
1297 	req->rq_private_buf.len = transport->tcp_copied;
1298 
1299 	return 0;
1300 }
1301 
1302 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1303 					struct xdr_skb_reader *desc)
1304 {
1305 	struct sock_xprt *transport =
1306 				container_of(xprt, struct sock_xprt, xprt);
1307 
1308 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1309 		xs_tcp_read_reply(xprt, desc) :
1310 		xs_tcp_read_callback(xprt, desc);
1311 }
1312 #else
1313 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1314 					struct xdr_skb_reader *desc)
1315 {
1316 	return xs_tcp_read_reply(xprt, desc);
1317 }
1318 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1319 
1320 /*
1321  * Read data off the transport.  This can be either an RPC_CALL or an
1322  * RPC_REPLY.  Relay the processing to helper functions.
1323  */
1324 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1325 				    struct xdr_skb_reader *desc)
1326 {
1327 	struct sock_xprt *transport =
1328 				container_of(xprt, struct sock_xprt, xprt);
1329 
1330 	if (_xs_tcp_read_data(xprt, desc) == 0)
1331 		xs_tcp_check_fraghdr(transport);
1332 	else {
1333 		/*
1334 		 * The transport_lock protects the request handling.
1335 		 * There's no need to hold it to update the tcp_flags.
1336 		 */
1337 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1338 	}
1339 }
1340 
1341 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1342 {
1343 	size_t len;
1344 
1345 	len = transport->tcp_reclen - transport->tcp_offset;
1346 	if (len > desc->count)
1347 		len = desc->count;
1348 	desc->count -= len;
1349 	desc->offset += len;
1350 	transport->tcp_offset += len;
1351 	dprintk("RPC:       discarded %Zu bytes\n", len);
1352 	xs_tcp_check_fraghdr(transport);
1353 }
1354 
1355 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1356 {
1357 	struct rpc_xprt *xprt = rd_desc->arg.data;
1358 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1359 	struct xdr_skb_reader desc = {
1360 		.skb	= skb,
1361 		.offset	= offset,
1362 		.count	= len,
1363 	};
1364 
1365 	dprintk("RPC:       xs_tcp_data_recv started\n");
1366 	do {
1367 		/* Read in a new fragment marker if necessary */
1368 		/* Can we ever really expect to get completely empty fragments? */
1369 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1370 			xs_tcp_read_fraghdr(xprt, &desc);
1371 			continue;
1372 		}
1373 		/* Read in the xid if necessary */
1374 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1375 			xs_tcp_read_xid(transport, &desc);
1376 			continue;
1377 		}
1378 		/* Read in the call/reply flag */
1379 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1380 			xs_tcp_read_calldir(transport, &desc);
1381 			continue;
1382 		}
1383 		/* Read in the request data */
1384 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1385 			xs_tcp_read_data(xprt, &desc);
1386 			continue;
1387 		}
1388 		/* Skip over any trailing bytes on short reads */
1389 		xs_tcp_read_discard(transport, &desc);
1390 	} while (desc.count);
1391 	dprintk("RPC:       xs_tcp_data_recv done\n");
1392 	return len - desc.count;
1393 }
1394 
1395 /**
1396  * xs_tcp_data_ready - "data ready" callback for TCP sockets
1397  * @sk: socket with data to read
1398  * @bytes: how much data to read
1399  *
1400  */
1401 static void xs_tcp_data_ready(struct sock *sk, int bytes)
1402 {
1403 	struct rpc_xprt *xprt;
1404 	read_descriptor_t rd_desc;
1405 	int read;
1406 
1407 	dprintk("RPC:       xs_tcp_data_ready...\n");
1408 
1409 	read_lock_bh(&sk->sk_callback_lock);
1410 	if (!(xprt = xprt_from_sock(sk)))
1411 		goto out;
1412 	/* Any data means we had a useful conversation, so
1413 	 * the we don't need to delay the next reconnect
1414 	 */
1415 	if (xprt->reestablish_timeout)
1416 		xprt->reestablish_timeout = 0;
1417 
1418 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1419 	rd_desc.arg.data = xprt;
1420 	do {
1421 		rd_desc.count = 65536;
1422 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1423 	} while (read > 0);
1424 out:
1425 	read_unlock_bh(&sk->sk_callback_lock);
1426 }
1427 
1428 /*
1429  * Do the equivalent of linger/linger2 handling for dealing with
1430  * broken servers that don't close the socket in a timely
1431  * fashion
1432  */
1433 static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt,
1434 		unsigned long timeout)
1435 {
1436 	struct sock_xprt *transport;
1437 
1438 	if (xprt_test_and_set_connecting(xprt))
1439 		return;
1440 	set_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1441 	transport = container_of(xprt, struct sock_xprt, xprt);
1442 	queue_delayed_work(rpciod_workqueue, &transport->connect_worker,
1443 			   timeout);
1444 }
1445 
1446 static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
1447 {
1448 	struct sock_xprt *transport;
1449 
1450 	transport = container_of(xprt, struct sock_xprt, xprt);
1451 
1452 	if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) ||
1453 	    !cancel_delayed_work(&transport->connect_worker))
1454 		return;
1455 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1456 	xprt_clear_connecting(xprt);
1457 }
1458 
1459 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
1460 {
1461 	smp_mb__before_clear_bit();
1462 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1463 	clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1464 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1465 	clear_bit(XPRT_CLOSING, &xprt->state);
1466 	smp_mb__after_clear_bit();
1467 }
1468 
1469 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
1470 {
1471 	xs_sock_reset_connection_flags(xprt);
1472 	/* Mark transport as closed and wake up all pending tasks */
1473 	xprt_disconnect_done(xprt);
1474 }
1475 
1476 /**
1477  * xs_tcp_state_change - callback to handle TCP socket state changes
1478  * @sk: socket whose state has changed
1479  *
1480  */
1481 static void xs_tcp_state_change(struct sock *sk)
1482 {
1483 	struct rpc_xprt *xprt;
1484 
1485 	read_lock_bh(&sk->sk_callback_lock);
1486 	if (!(xprt = xprt_from_sock(sk)))
1487 		goto out;
1488 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1489 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1490 			sk->sk_state, xprt_connected(xprt),
1491 			sock_flag(sk, SOCK_DEAD),
1492 			sock_flag(sk, SOCK_ZAPPED),
1493 			sk->sk_shutdown);
1494 
1495 	switch (sk->sk_state) {
1496 	case TCP_ESTABLISHED:
1497 		spin_lock(&xprt->transport_lock);
1498 		if (!xprt_test_and_set_connected(xprt)) {
1499 			struct sock_xprt *transport = container_of(xprt,
1500 					struct sock_xprt, xprt);
1501 
1502 			/* Reset TCP record info */
1503 			transport->tcp_offset = 0;
1504 			transport->tcp_reclen = 0;
1505 			transport->tcp_copied = 0;
1506 			transport->tcp_flags =
1507 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1508 
1509 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1510 		}
1511 		spin_unlock(&xprt->transport_lock);
1512 		break;
1513 	case TCP_FIN_WAIT1:
1514 		/* The client initiated a shutdown of the socket */
1515 		xprt->connect_cookie++;
1516 		xprt->reestablish_timeout = 0;
1517 		set_bit(XPRT_CLOSING, &xprt->state);
1518 		smp_mb__before_clear_bit();
1519 		clear_bit(XPRT_CONNECTED, &xprt->state);
1520 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1521 		smp_mb__after_clear_bit();
1522 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1523 		break;
1524 	case TCP_CLOSE_WAIT:
1525 		/* The server initiated a shutdown of the socket */
1526 		xprt->connect_cookie++;
1527 		clear_bit(XPRT_CONNECTED, &xprt->state);
1528 		xs_tcp_force_close(xprt);
1529 	case TCP_CLOSING:
1530 		/*
1531 		 * If the server closed down the connection, make sure that
1532 		 * we back off before reconnecting
1533 		 */
1534 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1535 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1536 		break;
1537 	case TCP_LAST_ACK:
1538 		set_bit(XPRT_CLOSING, &xprt->state);
1539 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1540 		smp_mb__before_clear_bit();
1541 		clear_bit(XPRT_CONNECTED, &xprt->state);
1542 		smp_mb__after_clear_bit();
1543 		break;
1544 	case TCP_CLOSE:
1545 		xs_tcp_cancel_linger_timeout(xprt);
1546 		xs_sock_mark_closed(xprt);
1547 	}
1548  out:
1549 	read_unlock_bh(&sk->sk_callback_lock);
1550 }
1551 
1552 static void xs_write_space(struct sock *sk)
1553 {
1554 	struct socket *sock;
1555 	struct rpc_xprt *xprt;
1556 
1557 	if (unlikely(!(sock = sk->sk_socket)))
1558 		return;
1559 	clear_bit(SOCK_NOSPACE, &sock->flags);
1560 
1561 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1562 		return;
1563 	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
1564 		return;
1565 
1566 	xprt_write_space(xprt);
1567 }
1568 
1569 /**
1570  * xs_udp_write_space - callback invoked when socket buffer space
1571  *                             becomes available
1572  * @sk: socket whose state has changed
1573  *
1574  * Called when more output buffer space is available for this socket.
1575  * We try not to wake our writers until they can make "significant"
1576  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1577  * with a bunch of small requests.
1578  */
1579 static void xs_udp_write_space(struct sock *sk)
1580 {
1581 	read_lock_bh(&sk->sk_callback_lock);
1582 
1583 	/* from net/core/sock.c:sock_def_write_space */
1584 	if (sock_writeable(sk))
1585 		xs_write_space(sk);
1586 
1587 	read_unlock_bh(&sk->sk_callback_lock);
1588 }
1589 
1590 /**
1591  * xs_tcp_write_space - callback invoked when socket buffer space
1592  *                             becomes available
1593  * @sk: socket whose state has changed
1594  *
1595  * Called when more output buffer space is available for this socket.
1596  * We try not to wake our writers until they can make "significant"
1597  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1598  * with a bunch of small requests.
1599  */
1600 static void xs_tcp_write_space(struct sock *sk)
1601 {
1602 	read_lock_bh(&sk->sk_callback_lock);
1603 
1604 	/* from net/core/stream.c:sk_stream_write_space */
1605 	if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
1606 		xs_write_space(sk);
1607 
1608 	read_unlock_bh(&sk->sk_callback_lock);
1609 }
1610 
1611 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1612 {
1613 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1614 	struct sock *sk = transport->inet;
1615 
1616 	if (transport->rcvsize) {
1617 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1618 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1619 	}
1620 	if (transport->sndsize) {
1621 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1622 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1623 		sk->sk_write_space(sk);
1624 	}
1625 }
1626 
1627 /**
1628  * xs_udp_set_buffer_size - set send and receive limits
1629  * @xprt: generic transport
1630  * @sndsize: requested size of send buffer, in bytes
1631  * @rcvsize: requested size of receive buffer, in bytes
1632  *
1633  * Set socket send and receive buffer size limits.
1634  */
1635 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1636 {
1637 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1638 
1639 	transport->sndsize = 0;
1640 	if (sndsize)
1641 		transport->sndsize = sndsize + 1024;
1642 	transport->rcvsize = 0;
1643 	if (rcvsize)
1644 		transport->rcvsize = rcvsize + 1024;
1645 
1646 	xs_udp_do_set_buffer_size(xprt);
1647 }
1648 
1649 /**
1650  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1651  * @task: task that timed out
1652  *
1653  * Adjust the congestion window after a retransmit timeout has occurred.
1654  */
1655 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1656 {
1657 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1658 }
1659 
1660 static unsigned short xs_get_random_port(void)
1661 {
1662 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1663 	unsigned short rand = (unsigned short) net_random() % range;
1664 	return rand + xprt_min_resvport;
1665 }
1666 
1667 /**
1668  * xs_set_port - reset the port number in the remote endpoint address
1669  * @xprt: generic transport
1670  * @port: new port number
1671  *
1672  */
1673 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1674 {
1675 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1676 
1677 	rpc_set_port(xs_addr(xprt), port);
1678 	xs_update_peer_port(xprt);
1679 }
1680 
1681 static unsigned short xs_get_srcport(struct sock_xprt *transport)
1682 {
1683 	unsigned short port = transport->srcport;
1684 
1685 	if (port == 0 && transport->xprt.resvport)
1686 		port = xs_get_random_port();
1687 	return port;
1688 }
1689 
1690 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1691 {
1692 	if (transport->srcport != 0)
1693 		transport->srcport = 0;
1694 	if (!transport->xprt.resvport)
1695 		return 0;
1696 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1697 		return xprt_max_resvport;
1698 	return --port;
1699 }
1700 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1701 {
1702 	struct sockaddr_storage myaddr;
1703 	int err, nloop = 0;
1704 	unsigned short port = xs_get_srcport(transport);
1705 	unsigned short last;
1706 
1707 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1708 	do {
1709 		rpc_set_port((struct sockaddr *)&myaddr, port);
1710 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1711 				transport->xprt.addrlen);
1712 		if (port == 0)
1713 			break;
1714 		if (err == 0) {
1715 			transport->srcport = port;
1716 			break;
1717 		}
1718 		last = port;
1719 		port = xs_next_srcport(transport, port);
1720 		if (port > last)
1721 			nloop++;
1722 	} while (err == -EADDRINUSE && nloop != 2);
1723 
1724 	if (myaddr.ss_family == AF_INET)
1725 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1726 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1727 				port, err ? "failed" : "ok", err);
1728 	else
1729 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1730 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1731 				port, err ? "failed" : "ok", err);
1732 	return err;
1733 }
1734 
1735 /*
1736  * We don't support autobind on AF_LOCAL sockets
1737  */
1738 static void xs_local_rpcbind(struct rpc_task *task)
1739 {
1740 	rcu_read_lock();
1741 	xprt_set_bound(rcu_dereference(task->tk_client->cl_xprt));
1742 	rcu_read_unlock();
1743 }
1744 
1745 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1746 {
1747 }
1748 
1749 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1750 static struct lock_class_key xs_key[2];
1751 static struct lock_class_key xs_slock_key[2];
1752 
1753 static inline void xs_reclassify_socketu(struct socket *sock)
1754 {
1755 	struct sock *sk = sock->sk;
1756 
1757 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1758 		&xs_slock_key[1], "sk_lock-AF_LOCAL-RPC", &xs_key[1]);
1759 }
1760 
1761 static inline void xs_reclassify_socket4(struct socket *sock)
1762 {
1763 	struct sock *sk = sock->sk;
1764 
1765 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1766 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1767 }
1768 
1769 static inline void xs_reclassify_socket6(struct socket *sock)
1770 {
1771 	struct sock *sk = sock->sk;
1772 
1773 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1774 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1775 }
1776 
1777 static inline void xs_reclassify_socket(int family, struct socket *sock)
1778 {
1779 	WARN_ON_ONCE(sock_owned_by_user(sock->sk));
1780 	if (sock_owned_by_user(sock->sk))
1781 		return;
1782 
1783 	switch (family) {
1784 	case AF_LOCAL:
1785 		xs_reclassify_socketu(sock);
1786 		break;
1787 	case AF_INET:
1788 		xs_reclassify_socket4(sock);
1789 		break;
1790 	case AF_INET6:
1791 		xs_reclassify_socket6(sock);
1792 		break;
1793 	}
1794 }
1795 #else
1796 static inline void xs_reclassify_socketu(struct socket *sock)
1797 {
1798 }
1799 
1800 static inline void xs_reclassify_socket4(struct socket *sock)
1801 {
1802 }
1803 
1804 static inline void xs_reclassify_socket6(struct socket *sock)
1805 {
1806 }
1807 
1808 static inline void xs_reclassify_socket(int family, struct socket *sock)
1809 {
1810 }
1811 #endif
1812 
1813 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1814 		struct sock_xprt *transport, int family, int type, int protocol)
1815 {
1816 	struct socket *sock;
1817 	int err;
1818 
1819 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1820 	if (err < 0) {
1821 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1822 				protocol, -err);
1823 		goto out;
1824 	}
1825 	xs_reclassify_socket(family, sock);
1826 
1827 	err = xs_bind(transport, sock);
1828 	if (err) {
1829 		sock_release(sock);
1830 		goto out;
1831 	}
1832 
1833 	return sock;
1834 out:
1835 	return ERR_PTR(err);
1836 }
1837 
1838 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1839 				      struct socket *sock)
1840 {
1841 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1842 									xprt);
1843 
1844 	if (!transport->inet) {
1845 		struct sock *sk = sock->sk;
1846 
1847 		write_lock_bh(&sk->sk_callback_lock);
1848 
1849 		xs_save_old_callbacks(transport, sk);
1850 
1851 		sk->sk_user_data = xprt;
1852 		sk->sk_data_ready = xs_local_data_ready;
1853 		sk->sk_write_space = xs_udp_write_space;
1854 		sk->sk_allocation = GFP_ATOMIC;
1855 
1856 		xprt_clear_connected(xprt);
1857 
1858 		/* Reset to new socket */
1859 		transport->sock = sock;
1860 		transport->inet = sk;
1861 
1862 		write_unlock_bh(&sk->sk_callback_lock);
1863 	}
1864 
1865 	/* Tell the socket layer to start connecting... */
1866 	xprt->stat.connect_count++;
1867 	xprt->stat.connect_start = jiffies;
1868 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
1869 }
1870 
1871 /**
1872  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
1873  * @xprt: RPC transport to connect
1874  * @transport: socket transport to connect
1875  * @create_sock: function to create a socket of the correct type
1876  */
1877 static int xs_local_setup_socket(struct sock_xprt *transport)
1878 {
1879 	struct rpc_xprt *xprt = &transport->xprt;
1880 	struct socket *sock;
1881 	int status = -EIO;
1882 
1883 	current->flags |= PF_FSTRANS;
1884 
1885 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1886 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
1887 					SOCK_STREAM, 0, &sock, 1);
1888 	if (status < 0) {
1889 		dprintk("RPC:       can't create AF_LOCAL "
1890 			"transport socket (%d).\n", -status);
1891 		goto out;
1892 	}
1893 	xs_reclassify_socketu(sock);
1894 
1895 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
1896 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1897 
1898 	status = xs_local_finish_connecting(xprt, sock);
1899 	switch (status) {
1900 	case 0:
1901 		dprintk("RPC:       xprt %p connected to %s\n",
1902 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1903 		xprt_set_connected(xprt);
1904 		break;
1905 	case -ENOENT:
1906 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
1907 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1908 		break;
1909 	case -ECONNREFUSED:
1910 		dprintk("RPC:       xprt %p: connection refused for %s\n",
1911 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1912 		break;
1913 	default:
1914 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
1915 				__func__, -status,
1916 				xprt->address_strings[RPC_DISPLAY_ADDR]);
1917 	}
1918 
1919 out:
1920 	xprt_clear_connecting(xprt);
1921 	xprt_wake_pending_tasks(xprt, status);
1922 	current->flags &= ~PF_FSTRANS;
1923 	return status;
1924 }
1925 
1926 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
1927 {
1928 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1929 	int ret;
1930 
1931 	 if (RPC_IS_ASYNC(task)) {
1932 		/*
1933 		 * We want the AF_LOCAL connect to be resolved in the
1934 		 * filesystem namespace of the process making the rpc
1935 		 * call.  Thus we connect synchronously.
1936 		 *
1937 		 * If we want to support asynchronous AF_LOCAL calls,
1938 		 * we'll need to figure out how to pass a namespace to
1939 		 * connect.
1940 		 */
1941 		rpc_exit(task, -ENOTCONN);
1942 		return;
1943 	}
1944 	ret = xs_local_setup_socket(transport);
1945 	if (ret && !RPC_IS_SOFTCONN(task))
1946 		msleep_interruptible(15000);
1947 }
1948 
1949 #ifdef CONFIG_SUNRPC_SWAP
1950 static void xs_set_memalloc(struct rpc_xprt *xprt)
1951 {
1952 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1953 			xprt);
1954 
1955 	if (xprt->swapper)
1956 		sk_set_memalloc(transport->inet);
1957 }
1958 
1959 /**
1960  * xs_swapper - Tag this transport as being used for swap.
1961  * @xprt: transport to tag
1962  * @enable: enable/disable
1963  *
1964  */
1965 int xs_swapper(struct rpc_xprt *xprt, int enable)
1966 {
1967 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1968 			xprt);
1969 	int err = 0;
1970 
1971 	if (enable) {
1972 		xprt->swapper++;
1973 		xs_set_memalloc(xprt);
1974 	} else if (xprt->swapper) {
1975 		xprt->swapper--;
1976 		sk_clear_memalloc(transport->inet);
1977 	}
1978 
1979 	return err;
1980 }
1981 EXPORT_SYMBOL_GPL(xs_swapper);
1982 #else
1983 static void xs_set_memalloc(struct rpc_xprt *xprt)
1984 {
1985 }
1986 #endif
1987 
1988 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1989 {
1990 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1991 
1992 	if (!transport->inet) {
1993 		struct sock *sk = sock->sk;
1994 
1995 		write_lock_bh(&sk->sk_callback_lock);
1996 
1997 		xs_save_old_callbacks(transport, sk);
1998 
1999 		sk->sk_user_data = xprt;
2000 		sk->sk_data_ready = xs_udp_data_ready;
2001 		sk->sk_write_space = xs_udp_write_space;
2002 		sk->sk_no_check = UDP_CSUM_NORCV;
2003 		sk->sk_allocation = GFP_ATOMIC;
2004 
2005 		xprt_set_connected(xprt);
2006 
2007 		/* Reset to new socket */
2008 		transport->sock = sock;
2009 		transport->inet = sk;
2010 
2011 		xs_set_memalloc(xprt);
2012 
2013 		write_unlock_bh(&sk->sk_callback_lock);
2014 	}
2015 	xs_udp_do_set_buffer_size(xprt);
2016 }
2017 
2018 static void xs_udp_setup_socket(struct work_struct *work)
2019 {
2020 	struct sock_xprt *transport =
2021 		container_of(work, struct sock_xprt, connect_worker.work);
2022 	struct rpc_xprt *xprt = &transport->xprt;
2023 	struct socket *sock = transport->sock;
2024 	int status = -EIO;
2025 
2026 	current->flags |= PF_FSTRANS;
2027 
2028 	/* Start by resetting any existing state */
2029 	xs_reset_transport(transport);
2030 	sock = xs_create_sock(xprt, transport,
2031 			xs_addr(xprt)->sa_family, SOCK_DGRAM, IPPROTO_UDP);
2032 	if (IS_ERR(sock))
2033 		goto out;
2034 
2035 	dprintk("RPC:       worker connecting xprt %p via %s to "
2036 				"%s (port %s)\n", xprt,
2037 			xprt->address_strings[RPC_DISPLAY_PROTO],
2038 			xprt->address_strings[RPC_DISPLAY_ADDR],
2039 			xprt->address_strings[RPC_DISPLAY_PORT]);
2040 
2041 	xs_udp_finish_connecting(xprt, sock);
2042 	status = 0;
2043 out:
2044 	xprt_clear_connecting(xprt);
2045 	xprt_wake_pending_tasks(xprt, status);
2046 	current->flags &= ~PF_FSTRANS;
2047 }
2048 
2049 /*
2050  * We need to preserve the port number so the reply cache on the server can
2051  * find our cached RPC replies when we get around to reconnecting.
2052  */
2053 static void xs_abort_connection(struct sock_xprt *transport)
2054 {
2055 	int result;
2056 	struct sockaddr any;
2057 
2058 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", transport);
2059 
2060 	/*
2061 	 * Disconnect the transport socket by doing a connect operation
2062 	 * with AF_UNSPEC.  This should return immediately...
2063 	 */
2064 	memset(&any, 0, sizeof(any));
2065 	any.sa_family = AF_UNSPEC;
2066 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
2067 	if (!result)
2068 		xs_sock_reset_connection_flags(&transport->xprt);
2069 	dprintk("RPC:       AF_UNSPEC connect return code %d\n", result);
2070 }
2071 
2072 static void xs_tcp_reuse_connection(struct sock_xprt *transport)
2073 {
2074 	unsigned int state = transport->inet->sk_state;
2075 
2076 	if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED) {
2077 		/* we don't need to abort the connection if the socket
2078 		 * hasn't undergone a shutdown
2079 		 */
2080 		if (transport->inet->sk_shutdown == 0)
2081 			return;
2082 		dprintk("RPC:       %s: TCP_CLOSEd and sk_shutdown set to %d\n",
2083 				__func__, transport->inet->sk_shutdown);
2084 	}
2085 	if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT)) {
2086 		/* we don't need to abort the connection if the socket
2087 		 * hasn't undergone a shutdown
2088 		 */
2089 		if (transport->inet->sk_shutdown == 0)
2090 			return;
2091 		dprintk("RPC:       %s: ESTABLISHED/SYN_SENT "
2092 				"sk_shutdown set to %d\n",
2093 				__func__, transport->inet->sk_shutdown);
2094 	}
2095 	xs_abort_connection(transport);
2096 }
2097 
2098 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2099 {
2100 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2101 	int ret = -ENOTCONN;
2102 
2103 	if (!transport->inet) {
2104 		struct sock *sk = sock->sk;
2105 
2106 		write_lock_bh(&sk->sk_callback_lock);
2107 
2108 		xs_save_old_callbacks(transport, sk);
2109 
2110 		sk->sk_user_data = xprt;
2111 		sk->sk_data_ready = xs_tcp_data_ready;
2112 		sk->sk_state_change = xs_tcp_state_change;
2113 		sk->sk_write_space = xs_tcp_write_space;
2114 		sk->sk_allocation = GFP_ATOMIC;
2115 
2116 		/* socket options */
2117 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
2118 		sock_reset_flag(sk, SOCK_LINGER);
2119 		tcp_sk(sk)->linger2 = 0;
2120 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
2121 
2122 		xprt_clear_connected(xprt);
2123 
2124 		/* Reset to new socket */
2125 		transport->sock = sock;
2126 		transport->inet = sk;
2127 
2128 		write_unlock_bh(&sk->sk_callback_lock);
2129 	}
2130 
2131 	if (!xprt_bound(xprt))
2132 		goto out;
2133 
2134 	xs_set_memalloc(xprt);
2135 
2136 	/* Tell the socket layer to start connecting... */
2137 	xprt->stat.connect_count++;
2138 	xprt->stat.connect_start = jiffies;
2139 	ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2140 	switch (ret) {
2141 	case 0:
2142 	case -EINPROGRESS:
2143 		/* SYN_SENT! */
2144 		xprt->connect_cookie++;
2145 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2146 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2147 	}
2148 out:
2149 	return ret;
2150 }
2151 
2152 /**
2153  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2154  * @xprt: RPC transport to connect
2155  * @transport: socket transport to connect
2156  * @create_sock: function to create a socket of the correct type
2157  *
2158  * Invoked by a work queue tasklet.
2159  */
2160 static void xs_tcp_setup_socket(struct work_struct *work)
2161 {
2162 	struct sock_xprt *transport =
2163 		container_of(work, struct sock_xprt, connect_worker.work);
2164 	struct socket *sock = transport->sock;
2165 	struct rpc_xprt *xprt = &transport->xprt;
2166 	int status = -EIO;
2167 
2168 	current->flags |= PF_FSTRANS;
2169 
2170 	if (!sock) {
2171 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
2172 		sock = xs_create_sock(xprt, transport,
2173 				xs_addr(xprt)->sa_family, SOCK_STREAM, IPPROTO_TCP);
2174 		if (IS_ERR(sock)) {
2175 			status = PTR_ERR(sock);
2176 			goto out;
2177 		}
2178 	} else {
2179 		int abort_and_exit;
2180 
2181 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
2182 				&xprt->state);
2183 		/* "close" the socket, preserving the local port */
2184 		xs_tcp_reuse_connection(transport);
2185 
2186 		if (abort_and_exit)
2187 			goto out_eagain;
2188 	}
2189 
2190 	dprintk("RPC:       worker connecting xprt %p via %s to "
2191 				"%s (port %s)\n", xprt,
2192 			xprt->address_strings[RPC_DISPLAY_PROTO],
2193 			xprt->address_strings[RPC_DISPLAY_ADDR],
2194 			xprt->address_strings[RPC_DISPLAY_PORT]);
2195 
2196 	status = xs_tcp_finish_connecting(xprt, sock);
2197 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2198 			xprt, -status, xprt_connected(xprt),
2199 			sock->sk->sk_state);
2200 	switch (status) {
2201 	default:
2202 		printk("%s: connect returned unhandled error %d\n",
2203 			__func__, status);
2204 	case -EADDRNOTAVAIL:
2205 		/* We're probably in TIME_WAIT. Get rid of existing socket,
2206 		 * and retry
2207 		 */
2208 		xs_tcp_force_close(xprt);
2209 		break;
2210 	case -ECONNREFUSED:
2211 	case -ECONNRESET:
2212 	case -ENETUNREACH:
2213 		/* retry with existing socket, after a delay */
2214 	case 0:
2215 	case -EINPROGRESS:
2216 	case -EALREADY:
2217 		xprt_clear_connecting(xprt);
2218 		current->flags &= ~PF_FSTRANS;
2219 		return;
2220 	case -EINVAL:
2221 		/* Happens, for instance, if the user specified a link
2222 		 * local IPv6 address without a scope-id.
2223 		 */
2224 		goto out;
2225 	}
2226 out_eagain:
2227 	status = -EAGAIN;
2228 out:
2229 	xprt_clear_connecting(xprt);
2230 	xprt_wake_pending_tasks(xprt, status);
2231 	current->flags &= ~PF_FSTRANS;
2232 }
2233 
2234 /**
2235  * xs_connect - connect a socket to a remote endpoint
2236  * @xprt: pointer to transport structure
2237  * @task: address of RPC task that manages state of connect request
2238  *
2239  * TCP: If the remote end dropped the connection, delay reconnecting.
2240  *
2241  * UDP socket connects are synchronous, but we use a work queue anyway
2242  * to guarantee that even unprivileged user processes can set up a
2243  * socket on a privileged port.
2244  *
2245  * If a UDP socket connect fails, the delay behavior here prevents
2246  * retry floods (hard mounts).
2247  */
2248 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2249 {
2250 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2251 
2252 	if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) {
2253 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2254 				"seconds\n",
2255 				xprt, xprt->reestablish_timeout / HZ);
2256 		queue_delayed_work(rpciod_workqueue,
2257 				   &transport->connect_worker,
2258 				   xprt->reestablish_timeout);
2259 		xprt->reestablish_timeout <<= 1;
2260 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2261 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2262 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
2263 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
2264 	} else {
2265 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2266 		queue_delayed_work(rpciod_workqueue,
2267 				   &transport->connect_worker, 0);
2268 	}
2269 }
2270 
2271 /**
2272  * xs_local_print_stats - display AF_LOCAL socket-specifc stats
2273  * @xprt: rpc_xprt struct containing statistics
2274  * @seq: output file
2275  *
2276  */
2277 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2278 {
2279 	long idle_time = 0;
2280 
2281 	if (xprt_connected(xprt))
2282 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2283 
2284 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2285 			"%llu %llu %lu %llu %llu\n",
2286 			xprt->stat.bind_count,
2287 			xprt->stat.connect_count,
2288 			xprt->stat.connect_time,
2289 			idle_time,
2290 			xprt->stat.sends,
2291 			xprt->stat.recvs,
2292 			xprt->stat.bad_xids,
2293 			xprt->stat.req_u,
2294 			xprt->stat.bklog_u,
2295 			xprt->stat.max_slots,
2296 			xprt->stat.sending_u,
2297 			xprt->stat.pending_u);
2298 }
2299 
2300 /**
2301  * xs_udp_print_stats - display UDP socket-specifc stats
2302  * @xprt: rpc_xprt struct containing statistics
2303  * @seq: output file
2304  *
2305  */
2306 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2307 {
2308 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2309 
2310 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2311 			"%lu %llu %llu\n",
2312 			transport->srcport,
2313 			xprt->stat.bind_count,
2314 			xprt->stat.sends,
2315 			xprt->stat.recvs,
2316 			xprt->stat.bad_xids,
2317 			xprt->stat.req_u,
2318 			xprt->stat.bklog_u,
2319 			xprt->stat.max_slots,
2320 			xprt->stat.sending_u,
2321 			xprt->stat.pending_u);
2322 }
2323 
2324 /**
2325  * xs_tcp_print_stats - display TCP socket-specifc stats
2326  * @xprt: rpc_xprt struct containing statistics
2327  * @seq: output file
2328  *
2329  */
2330 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2331 {
2332 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2333 	long idle_time = 0;
2334 
2335 	if (xprt_connected(xprt))
2336 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2337 
2338 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2339 			"%llu %llu %lu %llu %llu\n",
2340 			transport->srcport,
2341 			xprt->stat.bind_count,
2342 			xprt->stat.connect_count,
2343 			xprt->stat.connect_time,
2344 			idle_time,
2345 			xprt->stat.sends,
2346 			xprt->stat.recvs,
2347 			xprt->stat.bad_xids,
2348 			xprt->stat.req_u,
2349 			xprt->stat.bklog_u,
2350 			xprt->stat.max_slots,
2351 			xprt->stat.sending_u,
2352 			xprt->stat.pending_u);
2353 }
2354 
2355 /*
2356  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2357  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2358  * to use the server side send routines.
2359  */
2360 static void *bc_malloc(struct rpc_task *task, size_t size)
2361 {
2362 	struct page *page;
2363 	struct rpc_buffer *buf;
2364 
2365 	WARN_ON_ONCE(size > PAGE_SIZE - sizeof(struct rpc_buffer));
2366 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer))
2367 		return NULL;
2368 
2369 	page = alloc_page(GFP_KERNEL);
2370 	if (!page)
2371 		return NULL;
2372 
2373 	buf = page_address(page);
2374 	buf->len = PAGE_SIZE;
2375 
2376 	return buf->data;
2377 }
2378 
2379 /*
2380  * Free the space allocated in the bc_alloc routine
2381  */
2382 static void bc_free(void *buffer)
2383 {
2384 	struct rpc_buffer *buf;
2385 
2386 	if (!buffer)
2387 		return;
2388 
2389 	buf = container_of(buffer, struct rpc_buffer, data);
2390 	free_page((unsigned long)buf);
2391 }
2392 
2393 /*
2394  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2395  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2396  */
2397 static int bc_sendto(struct rpc_rqst *req)
2398 {
2399 	int len;
2400 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2401 	struct rpc_xprt *xprt = req->rq_xprt;
2402 	struct sock_xprt *transport =
2403 				container_of(xprt, struct sock_xprt, xprt);
2404 	struct socket *sock = transport->sock;
2405 	unsigned long headoff;
2406 	unsigned long tailoff;
2407 
2408 	xs_encode_stream_record_marker(xbufp);
2409 
2410 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2411 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2412 	len = svc_send_common(sock, xbufp,
2413 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2414 			      xbufp->tail[0].iov_base, tailoff);
2415 
2416 	if (len != xbufp->len) {
2417 		printk(KERN_NOTICE "Error sending entire callback!\n");
2418 		len = -EAGAIN;
2419 	}
2420 
2421 	return len;
2422 }
2423 
2424 /*
2425  * The send routine. Borrows from svc_send
2426  */
2427 static int bc_send_request(struct rpc_task *task)
2428 {
2429 	struct rpc_rqst *req = task->tk_rqstp;
2430 	struct svc_xprt	*xprt;
2431 	u32                     len;
2432 
2433 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2434 	/*
2435 	 * Get the server socket associated with this callback xprt
2436 	 */
2437 	xprt = req->rq_xprt->bc_xprt;
2438 
2439 	/*
2440 	 * Grab the mutex to serialize data as the connection is shared
2441 	 * with the fore channel
2442 	 */
2443 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2444 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2445 		if (!mutex_trylock(&xprt->xpt_mutex))
2446 			return -EAGAIN;
2447 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2448 	}
2449 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2450 		len = -ENOTCONN;
2451 	else
2452 		len = bc_sendto(req);
2453 	mutex_unlock(&xprt->xpt_mutex);
2454 
2455 	if (len > 0)
2456 		len = 0;
2457 
2458 	return len;
2459 }
2460 
2461 /*
2462  * The close routine. Since this is client initiated, we do nothing
2463  */
2464 
2465 static void bc_close(struct rpc_xprt *xprt)
2466 {
2467 }
2468 
2469 /*
2470  * The xprt destroy routine. Again, because this connection is client
2471  * initiated, we do nothing
2472  */
2473 
2474 static void bc_destroy(struct rpc_xprt *xprt)
2475 {
2476 }
2477 
2478 static struct rpc_xprt_ops xs_local_ops = {
2479 	.reserve_xprt		= xprt_reserve_xprt,
2480 	.release_xprt		= xs_tcp_release_xprt,
2481 	.alloc_slot		= xprt_alloc_slot,
2482 	.rpcbind		= xs_local_rpcbind,
2483 	.set_port		= xs_local_set_port,
2484 	.connect		= xs_local_connect,
2485 	.buf_alloc		= rpc_malloc,
2486 	.buf_free		= rpc_free,
2487 	.send_request		= xs_local_send_request,
2488 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2489 	.close			= xs_close,
2490 	.destroy		= xs_local_destroy,
2491 	.print_stats		= xs_local_print_stats,
2492 };
2493 
2494 static struct rpc_xprt_ops xs_udp_ops = {
2495 	.set_buffer_size	= xs_udp_set_buffer_size,
2496 	.reserve_xprt		= xprt_reserve_xprt_cong,
2497 	.release_xprt		= xprt_release_xprt_cong,
2498 	.alloc_slot		= xprt_alloc_slot,
2499 	.rpcbind		= rpcb_getport_async,
2500 	.set_port		= xs_set_port,
2501 	.connect		= xs_connect,
2502 	.buf_alloc		= rpc_malloc,
2503 	.buf_free		= rpc_free,
2504 	.send_request		= xs_udp_send_request,
2505 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2506 	.timer			= xs_udp_timer,
2507 	.release_request	= xprt_release_rqst_cong,
2508 	.close			= xs_close,
2509 	.destroy		= xs_destroy,
2510 	.print_stats		= xs_udp_print_stats,
2511 };
2512 
2513 static struct rpc_xprt_ops xs_tcp_ops = {
2514 	.reserve_xprt		= xprt_reserve_xprt,
2515 	.release_xprt		= xs_tcp_release_xprt,
2516 	.alloc_slot		= xprt_lock_and_alloc_slot,
2517 	.rpcbind		= rpcb_getport_async,
2518 	.set_port		= xs_set_port,
2519 	.connect		= xs_connect,
2520 	.buf_alloc		= rpc_malloc,
2521 	.buf_free		= rpc_free,
2522 	.send_request		= xs_tcp_send_request,
2523 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2524 	.close			= xs_tcp_close,
2525 	.destroy		= xs_destroy,
2526 	.print_stats		= xs_tcp_print_stats,
2527 };
2528 
2529 /*
2530  * The rpc_xprt_ops for the server backchannel
2531  */
2532 
2533 static struct rpc_xprt_ops bc_tcp_ops = {
2534 	.reserve_xprt		= xprt_reserve_xprt,
2535 	.release_xprt		= xprt_release_xprt,
2536 	.alloc_slot		= xprt_alloc_slot,
2537 	.rpcbind		= xs_local_rpcbind,
2538 	.buf_alloc		= bc_malloc,
2539 	.buf_free		= bc_free,
2540 	.send_request		= bc_send_request,
2541 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2542 	.close			= bc_close,
2543 	.destroy		= bc_destroy,
2544 	.print_stats		= xs_tcp_print_stats,
2545 };
2546 
2547 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2548 {
2549 	static const struct sockaddr_in sin = {
2550 		.sin_family		= AF_INET,
2551 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2552 	};
2553 	static const struct sockaddr_in6 sin6 = {
2554 		.sin6_family		= AF_INET6,
2555 		.sin6_addr		= IN6ADDR_ANY_INIT,
2556 	};
2557 
2558 	switch (family) {
2559 	case AF_LOCAL:
2560 		break;
2561 	case AF_INET:
2562 		memcpy(sap, &sin, sizeof(sin));
2563 		break;
2564 	case AF_INET6:
2565 		memcpy(sap, &sin6, sizeof(sin6));
2566 		break;
2567 	default:
2568 		dprintk("RPC:       %s: Bad address family\n", __func__);
2569 		return -EAFNOSUPPORT;
2570 	}
2571 	return 0;
2572 }
2573 
2574 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2575 				      unsigned int slot_table_size,
2576 				      unsigned int max_slot_table_size)
2577 {
2578 	struct rpc_xprt *xprt;
2579 	struct sock_xprt *new;
2580 
2581 	if (args->addrlen > sizeof(xprt->addr)) {
2582 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2583 		return ERR_PTR(-EBADF);
2584 	}
2585 
2586 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2587 			max_slot_table_size);
2588 	if (xprt == NULL) {
2589 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2590 				"rpc_xprt\n");
2591 		return ERR_PTR(-ENOMEM);
2592 	}
2593 
2594 	new = container_of(xprt, struct sock_xprt, xprt);
2595 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2596 	xprt->addrlen = args->addrlen;
2597 	if (args->srcaddr)
2598 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2599 	else {
2600 		int err;
2601 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2602 					(struct sockaddr *)&new->srcaddr);
2603 		if (err != 0) {
2604 			xprt_free(xprt);
2605 			return ERR_PTR(err);
2606 		}
2607 	}
2608 
2609 	return xprt;
2610 }
2611 
2612 static const struct rpc_timeout xs_local_default_timeout = {
2613 	.to_initval = 10 * HZ,
2614 	.to_maxval = 10 * HZ,
2615 	.to_retries = 2,
2616 };
2617 
2618 /**
2619  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2620  * @args: rpc transport creation arguments
2621  *
2622  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2623  */
2624 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2625 {
2626 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2627 	struct sock_xprt *transport;
2628 	struct rpc_xprt *xprt;
2629 	struct rpc_xprt *ret;
2630 
2631 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2632 			xprt_max_tcp_slot_table_entries);
2633 	if (IS_ERR(xprt))
2634 		return xprt;
2635 	transport = container_of(xprt, struct sock_xprt, xprt);
2636 
2637 	xprt->prot = 0;
2638 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2639 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2640 
2641 	xprt->bind_timeout = XS_BIND_TO;
2642 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2643 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2644 
2645 	xprt->ops = &xs_local_ops;
2646 	xprt->timeout = &xs_local_default_timeout;
2647 
2648 	switch (sun->sun_family) {
2649 	case AF_LOCAL:
2650 		if (sun->sun_path[0] != '/') {
2651 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2652 					sun->sun_path);
2653 			ret = ERR_PTR(-EINVAL);
2654 			goto out_err;
2655 		}
2656 		xprt_set_bound(xprt);
2657 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2658 		break;
2659 	default:
2660 		ret = ERR_PTR(-EAFNOSUPPORT);
2661 		goto out_err;
2662 	}
2663 
2664 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2665 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2666 
2667 	if (try_module_get(THIS_MODULE))
2668 		return xprt;
2669 	ret = ERR_PTR(-EINVAL);
2670 out_err:
2671 	xprt_free(xprt);
2672 	return ret;
2673 }
2674 
2675 static const struct rpc_timeout xs_udp_default_timeout = {
2676 	.to_initval = 5 * HZ,
2677 	.to_maxval = 30 * HZ,
2678 	.to_increment = 5 * HZ,
2679 	.to_retries = 5,
2680 };
2681 
2682 /**
2683  * xs_setup_udp - Set up transport to use a UDP socket
2684  * @args: rpc transport creation arguments
2685  *
2686  */
2687 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2688 {
2689 	struct sockaddr *addr = args->dstaddr;
2690 	struct rpc_xprt *xprt;
2691 	struct sock_xprt *transport;
2692 	struct rpc_xprt *ret;
2693 
2694 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2695 			xprt_udp_slot_table_entries);
2696 	if (IS_ERR(xprt))
2697 		return xprt;
2698 	transport = container_of(xprt, struct sock_xprt, xprt);
2699 
2700 	xprt->prot = IPPROTO_UDP;
2701 	xprt->tsh_size = 0;
2702 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2703 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2704 
2705 	xprt->bind_timeout = XS_BIND_TO;
2706 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2707 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2708 
2709 	xprt->ops = &xs_udp_ops;
2710 
2711 	xprt->timeout = &xs_udp_default_timeout;
2712 
2713 	switch (addr->sa_family) {
2714 	case AF_INET:
2715 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2716 			xprt_set_bound(xprt);
2717 
2718 		INIT_DELAYED_WORK(&transport->connect_worker,
2719 					xs_udp_setup_socket);
2720 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2721 		break;
2722 	case AF_INET6:
2723 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2724 			xprt_set_bound(xprt);
2725 
2726 		INIT_DELAYED_WORK(&transport->connect_worker,
2727 					xs_udp_setup_socket);
2728 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2729 		break;
2730 	default:
2731 		ret = ERR_PTR(-EAFNOSUPPORT);
2732 		goto out_err;
2733 	}
2734 
2735 	if (xprt_bound(xprt))
2736 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2737 				xprt->address_strings[RPC_DISPLAY_ADDR],
2738 				xprt->address_strings[RPC_DISPLAY_PORT],
2739 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2740 	else
2741 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2742 				xprt->address_strings[RPC_DISPLAY_ADDR],
2743 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2744 
2745 	if (try_module_get(THIS_MODULE))
2746 		return xprt;
2747 	ret = ERR_PTR(-EINVAL);
2748 out_err:
2749 	xprt_free(xprt);
2750 	return ret;
2751 }
2752 
2753 static const struct rpc_timeout xs_tcp_default_timeout = {
2754 	.to_initval = 60 * HZ,
2755 	.to_maxval = 60 * HZ,
2756 	.to_retries = 2,
2757 };
2758 
2759 /**
2760  * xs_setup_tcp - Set up transport to use a TCP socket
2761  * @args: rpc transport creation arguments
2762  *
2763  */
2764 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2765 {
2766 	struct sockaddr *addr = args->dstaddr;
2767 	struct rpc_xprt *xprt;
2768 	struct sock_xprt *transport;
2769 	struct rpc_xprt *ret;
2770 
2771 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2772 			xprt_max_tcp_slot_table_entries);
2773 	if (IS_ERR(xprt))
2774 		return xprt;
2775 	transport = container_of(xprt, struct sock_xprt, xprt);
2776 
2777 	xprt->prot = IPPROTO_TCP;
2778 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2779 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2780 
2781 	xprt->bind_timeout = XS_BIND_TO;
2782 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2783 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2784 
2785 	xprt->ops = &xs_tcp_ops;
2786 	xprt->timeout = &xs_tcp_default_timeout;
2787 
2788 	switch (addr->sa_family) {
2789 	case AF_INET:
2790 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2791 			xprt_set_bound(xprt);
2792 
2793 		INIT_DELAYED_WORK(&transport->connect_worker,
2794 					xs_tcp_setup_socket);
2795 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
2796 		break;
2797 	case AF_INET6:
2798 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2799 			xprt_set_bound(xprt);
2800 
2801 		INIT_DELAYED_WORK(&transport->connect_worker,
2802 					xs_tcp_setup_socket);
2803 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
2804 		break;
2805 	default:
2806 		ret = ERR_PTR(-EAFNOSUPPORT);
2807 		goto out_err;
2808 	}
2809 
2810 	if (xprt_bound(xprt))
2811 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2812 				xprt->address_strings[RPC_DISPLAY_ADDR],
2813 				xprt->address_strings[RPC_DISPLAY_PORT],
2814 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2815 	else
2816 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2817 				xprt->address_strings[RPC_DISPLAY_ADDR],
2818 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2819 
2820 
2821 	if (try_module_get(THIS_MODULE))
2822 		return xprt;
2823 	ret = ERR_PTR(-EINVAL);
2824 out_err:
2825 	xprt_free(xprt);
2826 	return ret;
2827 }
2828 
2829 /**
2830  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
2831  * @args: rpc transport creation arguments
2832  *
2833  */
2834 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
2835 {
2836 	struct sockaddr *addr = args->dstaddr;
2837 	struct rpc_xprt *xprt;
2838 	struct sock_xprt *transport;
2839 	struct svc_sock *bc_sock;
2840 	struct rpc_xprt *ret;
2841 
2842 	if (args->bc_xprt->xpt_bc_xprt) {
2843 		/*
2844 		 * This server connection already has a backchannel
2845 		 * export; we can't create a new one, as we wouldn't be
2846 		 * able to match replies based on xid any more.  So,
2847 		 * reuse the already-existing one:
2848 		 */
2849 		 return args->bc_xprt->xpt_bc_xprt;
2850 	}
2851 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2852 			xprt_tcp_slot_table_entries);
2853 	if (IS_ERR(xprt))
2854 		return xprt;
2855 	transport = container_of(xprt, struct sock_xprt, xprt);
2856 
2857 	xprt->prot = IPPROTO_TCP;
2858 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2859 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2860 	xprt->timeout = &xs_tcp_default_timeout;
2861 
2862 	/* backchannel */
2863 	xprt_set_bound(xprt);
2864 	xprt->bind_timeout = 0;
2865 	xprt->reestablish_timeout = 0;
2866 	xprt->idle_timeout = 0;
2867 
2868 	xprt->ops = &bc_tcp_ops;
2869 
2870 	switch (addr->sa_family) {
2871 	case AF_INET:
2872 		xs_format_peer_addresses(xprt, "tcp",
2873 					 RPCBIND_NETID_TCP);
2874 		break;
2875 	case AF_INET6:
2876 		xs_format_peer_addresses(xprt, "tcp",
2877 				   RPCBIND_NETID_TCP6);
2878 		break;
2879 	default:
2880 		ret = ERR_PTR(-EAFNOSUPPORT);
2881 		goto out_err;
2882 	}
2883 
2884 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2885 			xprt->address_strings[RPC_DISPLAY_ADDR],
2886 			xprt->address_strings[RPC_DISPLAY_PORT],
2887 			xprt->address_strings[RPC_DISPLAY_PROTO]);
2888 
2889 	/*
2890 	 * Once we've associated a backchannel xprt with a connection,
2891 	 * we want to keep it around as long as long as the connection
2892 	 * lasts, in case we need to start using it for a backchannel
2893 	 * again; this reference won't be dropped until bc_xprt is
2894 	 * destroyed.
2895 	 */
2896 	xprt_get(xprt);
2897 	args->bc_xprt->xpt_bc_xprt = xprt;
2898 	xprt->bc_xprt = args->bc_xprt;
2899 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
2900 	transport->sock = bc_sock->sk_sock;
2901 	transport->inet = bc_sock->sk_sk;
2902 
2903 	/*
2904 	 * Since we don't want connections for the backchannel, we set
2905 	 * the xprt status to connected
2906 	 */
2907 	xprt_set_connected(xprt);
2908 
2909 
2910 	if (try_module_get(THIS_MODULE))
2911 		return xprt;
2912 	xprt_put(xprt);
2913 	ret = ERR_PTR(-EINVAL);
2914 out_err:
2915 	xprt_free(xprt);
2916 	return ret;
2917 }
2918 
2919 static struct xprt_class	xs_local_transport = {
2920 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
2921 	.name		= "named UNIX socket",
2922 	.owner		= THIS_MODULE,
2923 	.ident		= XPRT_TRANSPORT_LOCAL,
2924 	.setup		= xs_setup_local,
2925 };
2926 
2927 static struct xprt_class	xs_udp_transport = {
2928 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
2929 	.name		= "udp",
2930 	.owner		= THIS_MODULE,
2931 	.ident		= XPRT_TRANSPORT_UDP,
2932 	.setup		= xs_setup_udp,
2933 };
2934 
2935 static struct xprt_class	xs_tcp_transport = {
2936 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
2937 	.name		= "tcp",
2938 	.owner		= THIS_MODULE,
2939 	.ident		= XPRT_TRANSPORT_TCP,
2940 	.setup		= xs_setup_tcp,
2941 };
2942 
2943 static struct xprt_class	xs_bc_tcp_transport = {
2944 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
2945 	.name		= "tcp NFSv4.1 backchannel",
2946 	.owner		= THIS_MODULE,
2947 	.ident		= XPRT_TRANSPORT_BC_TCP,
2948 	.setup		= xs_setup_bc_tcp,
2949 };
2950 
2951 /**
2952  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
2953  *
2954  */
2955 int init_socket_xprt(void)
2956 {
2957 #ifdef RPC_DEBUG
2958 	if (!sunrpc_table_header)
2959 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
2960 #endif
2961 
2962 	xprt_register_transport(&xs_local_transport);
2963 	xprt_register_transport(&xs_udp_transport);
2964 	xprt_register_transport(&xs_tcp_transport);
2965 	xprt_register_transport(&xs_bc_tcp_transport);
2966 
2967 	return 0;
2968 }
2969 
2970 /**
2971  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
2972  *
2973  */
2974 void cleanup_socket_xprt(void)
2975 {
2976 #ifdef RPC_DEBUG
2977 	if (sunrpc_table_header) {
2978 		unregister_sysctl_table(sunrpc_table_header);
2979 		sunrpc_table_header = NULL;
2980 	}
2981 #endif
2982 
2983 	xprt_unregister_transport(&xs_local_transport);
2984 	xprt_unregister_transport(&xs_udp_transport);
2985 	xprt_unregister_transport(&xs_tcp_transport);
2986 	xprt_unregister_transport(&xs_bc_tcp_transport);
2987 }
2988 
2989 static int param_set_uint_minmax(const char *val,
2990 		const struct kernel_param *kp,
2991 		unsigned int min, unsigned int max)
2992 {
2993 	unsigned long num;
2994 	int ret;
2995 
2996 	if (!val)
2997 		return -EINVAL;
2998 	ret = strict_strtoul(val, 0, &num);
2999 	if (ret == -EINVAL || num < min || num > max)
3000 		return -EINVAL;
3001 	*((unsigned int *)kp->arg) = num;
3002 	return 0;
3003 }
3004 
3005 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3006 {
3007 	return param_set_uint_minmax(val, kp,
3008 			RPC_MIN_RESVPORT,
3009 			RPC_MAX_RESVPORT);
3010 }
3011 
3012 static struct kernel_param_ops param_ops_portnr = {
3013 	.set = param_set_portnr,
3014 	.get = param_get_uint,
3015 };
3016 
3017 #define param_check_portnr(name, p) \
3018 	__param_check(name, p, unsigned int);
3019 
3020 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3021 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3022 
3023 static int param_set_slot_table_size(const char *val,
3024 				     const struct kernel_param *kp)
3025 {
3026 	return param_set_uint_minmax(val, kp,
3027 			RPC_MIN_SLOT_TABLE,
3028 			RPC_MAX_SLOT_TABLE);
3029 }
3030 
3031 static struct kernel_param_ops param_ops_slot_table_size = {
3032 	.set = param_set_slot_table_size,
3033 	.get = param_get_uint,
3034 };
3035 
3036 #define param_check_slot_table_size(name, p) \
3037 	__param_check(name, p, unsigned int);
3038 
3039 static int param_set_max_slot_table_size(const char *val,
3040 				     const struct kernel_param *kp)
3041 {
3042 	return param_set_uint_minmax(val, kp,
3043 			RPC_MIN_SLOT_TABLE,
3044 			RPC_MAX_SLOT_TABLE_LIMIT);
3045 }
3046 
3047 static struct kernel_param_ops param_ops_max_slot_table_size = {
3048 	.set = param_set_max_slot_table_size,
3049 	.get = param_get_uint,
3050 };
3051 
3052 #define param_check_max_slot_table_size(name, p) \
3053 	__param_check(name, p, unsigned int);
3054 
3055 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3056 		   slot_table_size, 0644);
3057 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3058 		   max_slot_table_size, 0644);
3059 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3060 		   slot_table_size, 0644);
3061 
3062