[linux.git] / fs / 9p / mux.c

/*
 * linux/fs/9p/mux.c
 *
 * Protocol Multiplexer
 *
 *  Copyright (C) 2004 by Eric Van Hensbergen <[email protected]>
 *  Copyright (C) 2004 by Latchesar Ionkov <[email protected]>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/kthread.h>
#include <linux/idr.h>

#include "debug.h"
#include "v9fs.h"
#include "9p.h"
#include "transport.h"
#include "conv.h"
#include "mux.h"

/**
 * dprintcond - print condition of session info
 * @v9ses: session info structure
 * @req: RPC request structure
 *
 */

static inline int
dprintcond(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
{
	dprintk(DEBUG_MUX, "condition: %d, %p\n", v9ses->transport->status,
		req->rcall);
	return 0;
}

/**
 * xread - force read of a certain number of bytes
 * @v9ses: session info structure
 * @ptr: pointer to buffer
 * @sz: number of bytes to read
 *
 * Chuck Cranor CS-533 project1
 */

static int xread(struct v9fs_session_info *v9ses, void *ptr, unsigned long sz)
{
	int rd = 0;
	int ret = 0;
	while (rd < sz) {
		ret = v9ses->transport->read(v9ses->transport, ptr, sz - rd);
		if (ret <= 0) {
			dprintk(DEBUG_ERROR, "xread errno %d\n", ret);
			return ret;
		}
		rd += ret;
		ptr += ret;
	}
	return (rd);
}

/**
 * read_message - read a full 9P2000 fcall packet
 * @v9ses: session info structure
 * @rcall: fcall structure to read into
 * @rcalllen: size of fcall buffer
 *
 */

static int
read_message(struct v9fs_session_info *v9ses,
	     struct v9fs_fcall *rcall, int rcalllen)
{
	unsigned char buf[4];
	void *data;
	int size = 0;
	int res = 0;

	res = xread(v9ses, buf, sizeof(buf));
	if (res < 0) {
		dprintk(DEBUG_ERROR,
			"Reading of count field failed returned: %d\n", res);
		return res;
	}

	if (res < 4) {
		dprintk(DEBUG_ERROR,
			"Reading of count field failed returned: %d\n", res);
		return -EIO;
	}

	size = buf[0] | (buf[1] << 8) | (buf[2] << 16) | (buf[3] << 24);
	dprintk(DEBUG_MUX, "got a packet count: %d\n", size);

	/* adjust for the four bytes of size */
	size -= 4;

	if (size > v9ses->maxdata) {
		dprintk(DEBUG_ERROR, "packet too big: %d\n", size);
		return -E2BIG;
	}

	data = kmalloc(size, GFP_KERNEL);
	if (!data) {
		eprintk(KERN_WARNING, "out of memory\n");
		return -ENOMEM;
	}

	res = xread(v9ses, data, size);
	if (res < size) {
		dprintk(DEBUG_ERROR, "Reading of fcall failed returned: %d\n",
			res);
		kfree(data);
		return res;
	}

	/* we now have an in-memory string that is the reply.
	 * deserialize it. There is very little to go wrong at this point
	 * save for v9fs_alloc errors.
	 */
	res = v9fs_deserialize_fcall(v9ses, size, data, v9ses->maxdata,
				     rcall, rcalllen);

	kfree(data);

	if (res < 0)
		return res;

	return 0;
}

/**
 * v9fs_recv - receive an RPC response for a particular tag
 * @v9ses: session info structure
 * @req: RPC request structure
 *
 */

static int v9fs_recv(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
{
	int ret = 0;

	dprintk(DEBUG_MUX, "waiting for response: %d\n", req->tcall->tag);
	ret = wait_event_interruptible(v9ses->read_wait,
		       ((v9ses->transport->status != Connected) ||
			(req->rcall != 0) || dprintcond(v9ses, req)));

	dprintk(DEBUG_MUX, "got it: rcall %p\n", req->rcall);
	if (v9ses->transport->status == Disconnected)
		return -ECONNRESET;

	if (ret == 0) {
		spin_lock(&v9ses->muxlock);
		list_del(&req->next);
		spin_unlock(&v9ses->muxlock);
	}

	return ret;
}

/**
 * v9fs_send - send a 9P request
 * @v9ses: session info structure
 * @req: RPC request to send
 *
 */

static int v9fs_send(struct v9fs_session_info *v9ses, struct v9fs_rpcreq *req)
{
	int ret = -1;
	void *data = NULL;
	struct v9fs_fcall *tcall = req->tcall;

	data = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	tcall->size = 0;	/* enforce size recalculation */
	ret =
	    v9fs_serialize_fcall(v9ses, tcall, data,
				 v9ses->maxdata + V9FS_IOHDRSZ);
	if (ret < 0)
		goto free_data;

	spin_lock(&v9ses->muxlock);
	list_add(&req->next, &v9ses->mux_fcalls);
	spin_unlock(&v9ses->muxlock);

	dprintk(DEBUG_MUX, "sending message: tag %d size %d\n", tcall->tag,
		tcall->size);
	ret = v9ses->transport->write(v9ses->transport, data, tcall->size);

	if (ret != tcall->size) {
		spin_lock(&v9ses->muxlock);
		list_del(&req->next);
		kfree(req->rcall);

		spin_unlock(&v9ses->muxlock);
		if (ret >= 0)
			ret = -EREMOTEIO;
	} else
		ret = 0;

      free_data:
	kfree(data);
	return ret;
}

/**
 * v9fs_mux_rpc - send a request, receive a response
 * @v9ses: session info structure
 * @tcall: fcall to send
 * @rcall: buffer to place response into
 *
 */

long
v9fs_mux_rpc(struct v9fs_session_info *v9ses, struct v9fs_fcall *tcall,
	     struct v9fs_fcall **rcall)
{
	int tid = -1;
	struct v9fs_fcall *fcall = NULL;
	struct v9fs_rpcreq req;
	int ret = -1;

	if (!v9ses)
		return -EINVAL;

	if (rcall)
		*rcall = NULL;

	if (tcall->id != TVERSION) {
		tid = v9fs_get_idpool(&v9ses->tidpool);
		if (tid < 0)
			return -ENOMEM;
	}

	tcall->tag = tid;

	req.tcall = tcall;
	req.rcall = NULL;

	ret = v9fs_send(v9ses, &req);

	if (ret < 0) {
		if (tcall->id != TVERSION)
			v9fs_put_idpool(tid, &v9ses->tidpool);
		dprintk(DEBUG_MUX, "error %d\n", ret);
		return ret;
	}

	ret = v9fs_recv(v9ses, &req);

	fcall = req.rcall;

	dprintk(DEBUG_MUX, "received: tag=%x, ret=%d\n", tcall->tag, ret);
	if (ret == -ERESTARTSYS) {
		if (v9ses->transport->status != Disconnected
		    && tcall->id != TFLUSH) {
			unsigned long flags;

			dprintk(DEBUG_MUX, "flushing the tag: %d\n",
				tcall->tag);
			clear_thread_flag(TIF_SIGPENDING);
			v9fs_t_flush(v9ses, tcall->tag);
			spin_lock_irqsave(&current->sighand->siglock, flags);
			recalc_sigpending();
			spin_unlock_irqrestore(&current->sighand->siglock,
					       flags);
			dprintk(DEBUG_MUX, "flushing done\n");
		}

		goto release_req;
	} else if (ret < 0)
		goto release_req;

	if (!fcall)
		ret = -EIO;
	else {
		if (fcall->id == RERROR) {
			ret = v9fs_errstr2errno(fcall->params.rerror.error);
			if (ret == 0) {	/* string match failed */
				if (fcall->params.rerror.errno)
					ret = -(fcall->params.rerror.errno);
				else
					ret = -ESERVERFAULT;
			}
		} else if (fcall->id != tcall->id + 1) {
			dprintk(DEBUG_ERROR,
				"fcall mismatch: expected %d, got %d\n",
				tcall->id + 1, fcall->id);
			ret = -EIO;
		}
	}

      release_req:
	if (tcall->id != TVERSION)
		v9fs_put_idpool(tid, &v9ses->tidpool);
	if (rcall)
		*rcall = fcall;
	else
		kfree(fcall);

	return ret;
}

/**
 * v9fs_mux_cancel_requests - cancels all pending requests
 *
 * @v9ses: session info structure
 * @err: error code to return to the requests
 */
void v9fs_mux_cancel_requests(struct v9fs_session_info *v9ses, int err)
{
	struct v9fs_rpcreq *rptr;
	struct v9fs_rpcreq *rreq;

	dprintk(DEBUG_MUX, " %d\n", err);
	spin_lock(&v9ses->muxlock);
	list_for_each_entry_safe(rreq, rptr, &v9ses->mux_fcalls, next) {
		rreq->err = err;
	}
	spin_unlock(&v9ses->muxlock);
	wake_up_all(&v9ses->read_wait);
}

/**
 * v9fs_recvproc - kproc to handle demultiplexing responses
 * @data: session info structure
 *
 */

static int v9fs_recvproc(void *data)
{
	struct v9fs_session_info *v9ses = (struct v9fs_session_info *)data;
	struct v9fs_fcall *rcall = NULL;
	struct v9fs_rpcreq *rptr;
	struct v9fs_rpcreq *req;
	struct v9fs_rpcreq *rreq;
	int err = 0;

	allow_signal(SIGKILL);
	set_current_state(TASK_INTERRUPTIBLE);
	complete(&v9ses->proccmpl);
	while (!kthread_should_stop() && err >= 0) {
		req = rptr = rreq = NULL;

		rcall = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
		if (!rcall) {
			eprintk(KERN_ERR, "no memory for buffers\n");
			break;
		}

		err = read_message(v9ses, rcall, v9ses->maxdata + V9FS_IOHDRSZ);
		if (err < 0) {
			kfree(rcall);
			break;
		}
		spin_lock(&v9ses->muxlock);
		list_for_each_entry_safe(rreq, rptr, &v9ses->mux_fcalls, next) {
			if (rreq->tcall->tag == rcall->tag) {
				req = rreq;
				req->rcall = rcall;
				break;
			}
		}

		if (req && (req->tcall->id == TFLUSH)) {
			struct v9fs_rpcreq *treq = NULL;
			list_for_each_entry_safe(treq, rptr, &v9ses->mux_fcalls, next) {
				if (treq->tcall->tag ==
				    req->tcall->params.tflush.oldtag) {
					list_del(&rptr->next);
					kfree(treq->rcall);
					break;
				}
			}
		}

		spin_unlock(&v9ses->muxlock);

		if (!req) {
			dprintk(DEBUG_ERROR,
				"unexpected response: id %d tag %d\n",
				rcall->id, rcall->tag);

			kfree(rcall);
		}

		wake_up_all(&v9ses->read_wait);
		set_current_state(TASK_INTERRUPTIBLE);
	}

	/* Inform all pending processes about the failure */
	wake_up_all(&v9ses->read_wait);

	if (signal_pending(current))
		complete(&v9ses->proccmpl);

	dprintk(DEBUG_MUX, "recvproc: end\n");
	v9ses->recvproc = NULL;

	return err >= 0;
}

/**
 * v9fs_mux_init - initialize multiplexer (spawn kproc)
 * @v9ses: session info structure
 * @dev_name: mount device information (to create unique kproc)
 *
 */

int v9fs_mux_init(struct v9fs_session_info *v9ses, const char *dev_name)
{
	char procname[60];

	strncpy(procname, dev_name, sizeof(procname));
	procname[sizeof(procname) - 1] = 0;

	init_waitqueue_head(&v9ses->read_wait);
	init_completion(&v9ses->fcread);
	init_completion(&v9ses->proccmpl);
	spin_lock_init(&v9ses->muxlock);
	INIT_LIST_HEAD(&v9ses->mux_fcalls);
	v9ses->recvproc = NULL;
	v9ses->curfcall = NULL;

	v9ses->recvproc = kthread_create(v9fs_recvproc, v9ses,
					 "v9fs_recvproc %s", procname);

	if (IS_ERR(v9ses->recvproc)) {
		eprintk(KERN_ERR, "cannot create receiving thread\n");
		v9fs_session_close(v9ses);
		return -ECONNABORTED;
	}

	wake_up_process(v9ses->recvproc);
	wait_for_completion(&v9ses->proccmpl);

	return 0;
}
Commit	Line	Data
426cc91a EVH	1	/*
	2	* linux/fs/9p/mux.c
	3	*
	4	* Protocol Multiplexer
	5	*
	6	* Copyright (C) 2004 by Eric Van Hensbergen <[email protected]>
	7	* Copyright (C) 2004 by Latchesar Ionkov <[email protected]>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation; either version 2 of the License, or
	12	* (at your option) any later version.
	13	*
	14	* This program is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	* GNU General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License
	20	* along with this program; if not, write to:
	21	* Free Software Foundation
	22	* 51 Franklin Street, Fifth Floor
	23	* Boston, MA 02111-1301 USA
	24	*
	25	*/
	26
	27	#include <linux/config.h>
	28	#include <linux/module.h>
	29	#include <linux/errno.h>
	30	#include <linux/fs.h>
	31	#include <linux/kthread.h>
	32	#include <linux/idr.h>
	33
	34	#include "debug.h"
	35	#include "v9fs.h"
	36	#include "9p.h"
	37	#include "transport.h"
	38	#include "conv.h"
	39	#include "mux.h"
	40
	41	/**
	42	* dprintcond - print condition of session info
	43	* @v9ses: session info structure
	44	* @req: RPC request structure
	45	*
	46	*/
	47
	48	static inline int
	49	dprintcond(struct v9fs_session_info v9ses, struct v9fs_rpcreq req)
	50	{
	51	dprintk(DEBUG_MUX, "condition: %d, %p\n", v9ses->transport->status,
	52	req->rcall);
	53	return 0;
	54	}
	55
	56	/**
	57	* xread - force read of a certain number of bytes
	58	* @v9ses: session info structure
	59	* @ptr: pointer to buffer
	60	* @sz: number of bytes to read
	61	*
	62	* Chuck Cranor CS-533 project1
	63	*/
	64
65	static int xread(struct v9fs_session_info v9ses, void ptr, unsigned long sz)
66	{
67	int rd = 0;
68	int ret = 0;
69	while (rd < sz) {
70	ret = v9ses->transport->read(v9ses->transport, ptr, sz - rd);
71	if (ret <= 0) {
72	dprintk(DEBUG_ERROR, "xread errno %d\n", ret);
73	return ret;
74	}
75	rd += ret;
76	ptr += ret;
77	}
78	return (rd);
79	}
80
81	/**
82	* read_message - read a full 9P2000 fcall packet
83	* @v9ses: session info structure
84	* @rcall: fcall structure to read into
85	* @rcalllen: size of fcall buffer
86	*
87	*/
88
89	static int
90	read_message(struct v9fs_session_info *v9ses,
91	struct v9fs_fcall *rcall, int rcalllen)
92	{
93	unsigned char buf[4];
94	void *data;
95	int size = 0;
96	int res = 0;
97
98	res = xread(v9ses, buf, sizeof(buf));
99	if (res < 0) {
100	dprintk(DEBUG_ERROR,
101	"Reading of count field failed returned: %d\n", res);
102	return res;
103	}
104
105	if (res < 4) {
106	dprintk(DEBUG_ERROR,
107	"Reading of count field failed returned: %d\n", res);
108	return -EIO;
109	}
110
111	size = buf[0] \| (buf[1] << 8) \| (buf[2] << 16) \| (buf[3] << 24);
112	dprintk(DEBUG_MUX, "got a packet count: %d\n", size);
113
114	/* adjust for the four bytes of size */
115	size -= 4;
116
117	if (size > v9ses->maxdata) {
118	dprintk(DEBUG_ERROR, "packet too big: %d\n", size);
119	return -E2BIG;
120	}
121
122	data = kmalloc(size, GFP_KERNEL);
123	if (!data) {
124	eprintk(KERN_WARNING, "out of memory\n");
125	return -ENOMEM;
126	}
127
128	res = xread(v9ses, data, size);
129	if (res < size) {
130	dprintk(DEBUG_ERROR, "Reading of fcall failed returned: %d\n",
131	res);
132	kfree(data);
133	return res;
134	}
135
136	/* we now have an in-memory string that is the reply.
137	* deserialize it. There is very little to go wrong at this point
138	* save for v9fs_alloc errors.
139	*/
140	res = v9fs_deserialize_fcall(v9ses, size, data, v9ses->maxdata,
141	rcall, rcalllen);
142
143	kfree(data);
144
145	if (res < 0)
146	return res;
147
148	return 0;
149	}
150
151	/**
152	* v9fs_recv - receive an RPC response for a particular tag
153	* @v9ses: session info structure
154	* @req: RPC request structure
155	*
156	*/
157
158	static int v9fs_recv(struct v9fs_session_info v9ses, struct v9fs_rpcreq req)
159	{
160	int ret = 0;
161
162	dprintk(DEBUG_MUX, "waiting for response: %d\n", req->tcall->tag);
163	ret = wait_event_interruptible(v9ses->read_wait,
164	((v9ses->transport->status != Connected) \|\|
165	(req->rcall != 0) \|\| dprintcond(v9ses, req)));
166
167	dprintk(DEBUG_MUX, "got it: rcall %p\n", req->rcall);
168	if (v9ses->transport->status == Disconnected)
169	return -ECONNRESET;
170
171	if (ret == 0) {
172	spin_lock(&v9ses->muxlock);
173	list_del(&req->next);
174	spin_unlock(&v9ses->muxlock);
175	}
176
177	return ret;
178	}
179
180	/**
181	* v9fs_send - send a 9P request
182	* @v9ses: session info structure
183	* @req: RPC request to send
184	*
185	*/
186
187	static int v9fs_send(struct v9fs_session_info v9ses, struct v9fs_rpcreq req)
188	{
189	int ret = -1;
190	void *data = NULL;
191	struct v9fs_fcall *tcall = req->tcall;
192
193	data = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
194	if (!data)
195	return -ENOMEM;
196
197	tcall->size = 0; /* enforce size recalculation */
198	ret =
199	v9fs_serialize_fcall(v9ses, tcall, data,
200	v9ses->maxdata + V9FS_IOHDRSZ);
201	if (ret < 0)
202	goto free_data;
203
204	spin_lock(&v9ses->muxlock);
205	list_add(&req->next, &v9ses->mux_fcalls);
206	spin_unlock(&v9ses->muxlock);
207
208	dprintk(DEBUG_MUX, "sending message: tag %d size %d\n", tcall->tag,
209	tcall->size);
210	ret = v9ses->transport->write(v9ses->transport, data, tcall->size);
211
212	if (ret != tcall->size) {
213	spin_lock(&v9ses->muxlock);
214	list_del(&req->next);
215	kfree(req->rcall);
216
217	spin_unlock(&v9ses->muxlock);
218	if (ret >= 0)
219	ret = -EREMOTEIO;
220	} else
221	ret = 0;
222
223	free_data:
224	kfree(data);
225	return ret;
226	}
227
228	/**
229	* v9fs_mux_rpc - send a request, receive a response
230	* @v9ses: session info structure
231	* @tcall: fcall to send
232	* @rcall: buffer to place response into
233	*
234	*/
235
236	long
237	v9fs_mux_rpc(struct v9fs_session_info v9ses, struct v9fs_fcall tcall,
238	struct v9fs_fcall **rcall)
239	{
240	int tid = -1;
241	struct v9fs_fcall *fcall = NULL;
242	struct v9fs_rpcreq req;
243	int ret = -1;
244
245	if (!v9ses)
246	return -EINVAL;
247
248	if (rcall)
249	*rcall = NULL;
250
251	if (tcall->id != TVERSION) {
252	tid = v9fs_get_idpool(&v9ses->tidpool);
253	if (tid < 0)
254	return -ENOMEM;
255	}
256
257	tcall->tag = tid;
258
259	req.tcall = tcall;
260	req.rcall = NULL;
261
262	ret = v9fs_send(v9ses, &req);
263
264	if (ret < 0) {
265	if (tcall->id != TVERSION)
266	v9fs_put_idpool(tid, &v9ses->tidpool);
267	dprintk(DEBUG_MUX, "error %d\n", ret);
268	return ret;
269	}
270
271	ret = v9fs_recv(v9ses, &req);
272
273	fcall = req.rcall;
274
275	dprintk(DEBUG_MUX, "received: tag=%x, ret=%d\n", tcall->tag, ret);
276	if (ret == -ERESTARTSYS) {
277	if (v9ses->transport->status != Disconnected
278	&& tcall->id != TFLUSH) {
279	unsigned long flags;
280
281	dprintk(DEBUG_MUX, "flushing the tag: %d\n",
282	tcall->tag);
283	clear_thread_flag(TIF_SIGPENDING);
284	v9fs_t_flush(v9ses, tcall->tag);
285	spin_lock_irqsave(&current->sighand->siglock, flags);
286	recalc_sigpending();
287	spin_unlock_irqrestore(&current->sighand->siglock,
288	flags);
289	dprintk(DEBUG_MUX, "flushing done\n");
290	}
291
292	goto release_req;
293	} else if (ret < 0)
294	goto release_req;
295
296	if (!fcall)
297	ret = -EIO;
298	else {
299	if (fcall->id == RERROR) {
300	ret = v9fs_errstr2errno(fcall->params.rerror.error);
301	if (ret == 0) { /* string match failed */
302	if (fcall->params.rerror.errno)
303	ret = -(fcall->params.rerror.errno);
304	else
305	ret = -ESERVERFAULT;
306	}
307	} else if (fcall->id != tcall->id + 1) {
308	dprintk(DEBUG_ERROR,
309	"fcall mismatch: expected %d, got %d\n",
310	tcall->id + 1, fcall->id);
311	ret = -EIO;
312	}
313	}
314
315	release_req:
316	if (tcall->id != TVERSION)
317	v9fs_put_idpool(tid, &v9ses->tidpool);
318	if (rcall)
319	*rcall = fcall;
320	else
321	kfree(fcall);
322
323	return ret;
324	}
325
322b329a EVH	326	/**
	327	* v9fs_mux_cancel_requests - cancels all pending requests
	328	*
	329	* @v9ses: session info structure
	330	* @err: error code to return to the requests
	331	*/
	332	void v9fs_mux_cancel_requests(struct v9fs_session_info *v9ses, int err)
	333	{
	334	struct v9fs_rpcreq *rptr;
	335	struct v9fs_rpcreq *rreq;
	336
	337	dprintk(DEBUG_MUX, " %d\n", err);
	338	spin_lock(&v9ses->muxlock);
	339	list_for_each_entry_safe(rreq, rptr, &v9ses->mux_fcalls, next) {
	340	rreq->err = err;
	341	}
	342	spin_unlock(&v9ses->muxlock);
	343	wake_up_all(&v9ses->read_wait);
	344	}
	345
426cc91a EVH	346	/**
	347	* v9fs_recvproc - kproc to handle demultiplexing responses
	348	* @data: session info structure
	349	*
	350	*/
	351
	352	static int v9fs_recvproc(void *data)
	353	{
	354	struct v9fs_session_info v9ses = (struct v9fs_session_info )data;
	355	struct v9fs_fcall *rcall = NULL;
	356	struct v9fs_rpcreq *rptr;
	357	struct v9fs_rpcreq *req;
	358	struct v9fs_rpcreq *rreq;
	359	int err = 0;
	360
	361	allow_signal(SIGKILL);
	362	set_current_state(TASK_INTERRUPTIBLE);
	363	complete(&v9ses->proccmpl);
	364	while (!kthread_should_stop() && err >= 0) {
	365	req = rptr = rreq = NULL;
	366
	367	rcall = kmalloc(v9ses->maxdata + V9FS_IOHDRSZ, GFP_KERNEL);
	368	if (!rcall) {
	369	eprintk(KERN_ERR, "no memory for buffers\n");
	370	break;
	371	}
	372
	373	err = read_message(v9ses, rcall, v9ses->maxdata + V9FS_IOHDRSZ);
	374	if (err < 0) {
	375	kfree(rcall);
	376	break;
	377	}
	378	spin_lock(&v9ses->muxlock);
	379	list_for_each_entry_safe(rreq, rptr, &v9ses->mux_fcalls, next) {
	380	if (rreq->tcall->tag == rcall->tag) {
	381	req = rreq;
	382	req->rcall = rcall;
	383	break;
	384	}
	385	}
	386
	387	if (req && (req->tcall->id == TFLUSH)) {
	388	struct v9fs_rpcreq *treq = NULL;
	389	list_for_each_entry_safe(treq, rptr, &v9ses->mux_fcalls, next) {
	390	if (treq->tcall->tag ==
	391	req->tcall->params.tflush.oldtag) {
	392	list_del(&rptr->next);
	393	kfree(treq->rcall);
	394	break;
	395	}
	396	}
	397	}
	398
	399	spin_unlock(&v9ses->muxlock);
	400
	401	if (!req) {
	402	dprintk(DEBUG_ERROR,
	403	"unexpected response: id %d tag %d\n",
	404	rcall->id, rcall->tag);
	405
	406	kfree(rcall);
	407	}
	408
	409	wake_up_all(&v9ses->read_wait);
410	set_current_state(TASK_INTERRUPTIBLE);
411	}
412
413	/* Inform all pending processes about the failure */
414	wake_up_all(&v9ses->read_wait);
415
416	if (signal_pending(current))
417	complete(&v9ses->proccmpl);
418
419	dprintk(DEBUG_MUX, "recvproc: end\n");
420	v9ses->recvproc = NULL;
421
422	return err >= 0;
423	}
424
425	/**
426	* v9fs_mux_init - initialize multiplexer (spawn kproc)
427	* @v9ses: session info structure
428	* @dev_name: mount device information (to create unique kproc)
429	*
430	*/
431
432	int v9fs_mux_init(struct v9fs_session_info v9ses, const char dev_name)
433	{
434	char procname[60];
435
436	strncpy(procname, dev_name, sizeof(procname));
437	procname[sizeof(procname) - 1] = 0;
438
439	init_waitqueue_head(&v9ses->read_wait);
440	init_completion(&v9ses->fcread);
441	init_completion(&v9ses->proccmpl);
442	spin_lock_init(&v9ses->muxlock);
443	INIT_LIST_HEAD(&v9ses->mux_fcalls);
444	v9ses->recvproc = NULL;
445	v9ses->curfcall = NULL;
446
447	v9ses->recvproc = kthread_create(v9fs_recvproc, v9ses,
448	"v9fs_recvproc %s", procname);
449
450	if (IS_ERR(v9ses->recvproc)) {
451	eprintk(KERN_ERR, "cannot create receiving thread\n");
452	v9fs_session_close(v9ses);
453	return -ECONNABORTED;
454	}
455
456	wake_up_process(v9ses->recvproc);
457	wait_for_completion(&v9ses->proccmpl);
458
459	return 0;
460	}