Merge branch 'master' of /home/davem/src/GIT/linux-2.6/

4 files changed, 222 insertions, 114 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 09d4f1e2e4a..e3e5bf4469c 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -46,6 +46,7 @@ enum {
 	Opt_msize,
 	Opt_trans,
 	Opt_legacy,
+	Opt_version,
 	Opt_err,
 };
 
@@ -53,9 +54,42 @@ static const match_table_t tokens = {
 	{Opt_msize, "msize=%u"},
 	{Opt_legacy, "noextend"},
 	{Opt_trans, "trans=%s"},
+	{Opt_version, "version=%s"},
 	{Opt_err, NULL},
 };
 
+inline int p9_is_proto_dotl(struct p9_client *clnt)
+{
+	return (clnt->proto_version == p9_proto_2000L);
+}
+EXPORT_SYMBOL(p9_is_proto_dotl);
+
+inline int p9_is_proto_dotu(struct p9_client *clnt)
+{
+	return (clnt->proto_version == p9_proto_2000u);
+}
+EXPORT_SYMBOL(p9_is_proto_dotu);
+
+/* Interpret mount option for protocol version */
+static unsigned char get_protocol_version(const substring_t *name)
+{
+	unsigned char version = -EINVAL;
+	if (!strncmp("9p2000", name->from, name->to-name->from)) {
+		version = p9_proto_legacy;
+		P9_DPRINTK(P9_DEBUG_9P, "Protocol version: Legacy\n");
+	} else if (!strncmp("9p2000.u", name->from, name->to-name->from)) {
+		version = p9_proto_2000u;
+		P9_DPRINTK(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
+	} else if (!strncmp("9p2000.L", name->from, name->to-name->from)) {
+		version = p9_proto_2000L;
+		P9_DPRINTK(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
+	} else {
+		P9_DPRINTK(P9_DEBUG_ERROR, "Unknown protocol version %s. ",
+							name->from);
+	}
+	return version;
+}
+
 static struct p9_req_t *
 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
 
@@ -75,7 +109,7 @@ static int parse_opts(char *opts, struct p9_client *clnt)
 	int option;
 	int ret = 0;
 
-	clnt->dotu = 1;
+	clnt->proto_version = p9_proto_2000u;
 	clnt->msize = 8192;
 
 	if (!opts)
@@ -118,7 +152,13 @@ static int parse_opts(char *opts, struct p9_client *clnt)
 			}
 			break;
 		case Opt_legacy:
-			clnt->dotu = 0;
+			clnt->proto_version = p9_proto_legacy;
+			break;
+		case Opt_version:
+			ret = get_protocol_version(&args[0]);
+			if (ret == -EINVAL)
+				goto free_and_return;
+			clnt->proto_version = ret;
 			break;
 		default:
 			continue;
@@ -410,14 +450,15 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
 		int ecode;
 		char *ename;
 
-		err = p9pdu_readf(req->rc, c->dotu, "s?d", &ename, &ecode);
+		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
+							&ename, &ecode);
 		if (err) {
 			P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse error%d\n",
 									err);
 			return err;
 		}
 
-		if (c->dotu)
+		if (p9_is_proto_dotu(c))
 			err = -ecode;
 
 		if (!err || !IS_ERR_VALUE(err))
@@ -515,7 +556,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 	/* marshall the data */
 	p9pdu_prepare(req->tc, tag, type);
 	va_start(ap, fmt);
-	err = p9pdu_vwritef(req->tc, c->dotu, fmt, ap);
+	err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
 	va_end(ap);
 	p9pdu_finalize(req->tc);
 
@@ -627,14 +668,31 @@ int p9_client_version(struct p9_client *c)
 	char *version;
 	int msize;
 
-	P9_DPRINTK(P9_DEBUG_9P, ">>> TVERSION msize %d extended %d\n",
-							c->msize, c->dotu);
-	req = p9_client_rpc(c, P9_TVERSION, "ds", c->msize,
-				c->dotu ? "9P2000.u" : "9P2000");
+	P9_DPRINTK(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
+						c->msize, c->proto_version);
+
+	switch (c->proto_version) {
+	case p9_proto_2000L:
+		req = p9_client_rpc(c, P9_TVERSION, "ds",
+					c->msize, "9P2000.L");
+		break;
+	case p9_proto_2000u:
+		req = p9_client_rpc(c, P9_TVERSION, "ds",
+					c->msize, "9P2000.u");
+		break;
+	case p9_proto_legacy:
+		req = p9_client_rpc(c, P9_TVERSION, "ds",
+					c->msize, "9P2000");
+		break;
+	default:
+		return -EINVAL;
+		break;
+	}
+
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
-	err = p9pdu_readf(req->rc, c->dotu, "ds", &msize, &version);
+	err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
 	if (err) {
 		P9_DPRINTK(P9_DEBUG_9P, "version error %d\n", err);
 		p9pdu_dump(1, req->rc);
@@ -642,10 +700,12 @@ int p9_client_version(struct p9_client *c)
 	}
 
 	P9_DPRINTK(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
-	if (!memcmp(version, "9P2000.u", 8))
-		c->dotu = 1;
-	else if (!memcmp(version, "9P2000", 6))
-		c->dotu = 0;
+	if (!strncmp(version, "9P2000.L", 8))
+		c->proto_version = p9_proto_2000L;
+	else if (!strncmp(version, "9P2000.u", 8))
+		c->proto_version = p9_proto_2000u;
+	else if (!strncmp(version, "9P2000", 6))
+		c->proto_version = p9_proto_legacy;
 	else {
 		err = -EREMOTEIO;
 		goto error;
@@ -700,8 +760,8 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
 		goto put_trans;
 	}
 
-	P9_DPRINTK(P9_DEBUG_MUX, "clnt %p trans %p msize %d dotu %d\n",
-		clnt, clnt->trans_mod, clnt->msize, clnt->dotu);
+	P9_DPRINTK(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
+		clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
 
 	err = clnt->trans_mod->create(clnt, dev_name, options);
 	if (err)
@@ -784,7 +844,7 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 		goto error;
 	}
 
-	err = p9pdu_readf(req->rc, clnt->dotu, "Q", &qid);
+	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
 	if (err) {
 		p9pdu_dump(1, req->rc);
 		p9_free_req(clnt, req);
@@ -833,7 +893,7 @@ p9_client_auth(struct p9_client *clnt, char *uname, u32 n_uname, char *aname)
 		goto error;
 	}
 
-	err = p9pdu_readf(req->rc, clnt->dotu, "Q", &qid);
+	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
 	if (err) {
 		p9pdu_dump(1, req->rc);
 		p9_free_req(clnt, req);
@@ -891,7 +951,7 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
 		goto error;
 	}
 
-	err = p9pdu_readf(req->rc, clnt->dotu, "R", &nwqids, &wqids);
+	err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
 	if (err) {
 		p9pdu_dump(1, req->rc);
 		p9_free_req(clnt, req);
@@ -952,7 +1012,7 @@ int p9_client_open(struct p9_fid *fid, int mode)
 		goto error;
 	}
 
-	err = p9pdu_readf(req->rc, clnt->dotu, "Qd", &qid, &iounit);
+	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
 	if (err) {
 		p9pdu_dump(1, req->rc);
 		goto free_and_error;
@@ -997,7 +1057,7 @@ int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, int mode,
 		goto error;
 	}
 
-	err = p9pdu_readf(req->rc, clnt->dotu, "Qd", &qid, &iounit);
+	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
 	if (err) {
 		p9pdu_dump(1, req->rc);
 		goto free_and_error;
@@ -1098,7 +1158,7 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
 		goto error;
 	}
 
-	err = p9pdu_readf(req->rc, clnt->dotu, "D", &count, &dataptr);
+	err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
 	if (err) {
 		p9pdu_dump(1, req->rc);
 		goto free_and_error;
@@ -1159,7 +1219,7 @@ p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
 		goto error;
 	}
 
-	err = p9pdu_readf(req->rc, clnt->dotu, "d", &count);
+	err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
 	if (err) {
 		p9pdu_dump(1, req->rc);
 		goto free_and_error;
@@ -1199,7 +1259,7 @@ struct p9_wstat *p9_client_stat(struct p9_fid *fid)
 		goto error;
 	}
 
-	err = p9pdu_readf(req->rc, clnt->dotu, "wS", &ignored, ret);
+	err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
 	if (err) {
 		p9pdu_dump(1, req->rc);
 		p9_free_req(clnt, req);
@@ -1226,7 +1286,7 @@ error:
 }
 EXPORT_SYMBOL(p9_client_stat);
 
-static int p9_client_statsize(struct p9_wstat *wst, int optional)
+static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
 {
 	int ret;
 
@@ -1245,7 +1305,7 @@ static int p9_client_statsize(struct p9_wstat *wst, int optional)
 	if (wst->muid)
 		ret += strlen(wst->muid);
 
-	if (optional) {
+	if (proto_version == p9_proto_2000u) {
 		ret += 2+4+4+4;	/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
 		if (wst->extension)
 			ret += strlen(wst->extension);
@@ -1262,7 +1322,7 @@ int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
 
 	err = 0;
 	clnt = fid->clnt;
-	wst->size = p9_client_statsize(wst, clnt->dotu);
+	wst->size = p9_client_statsize(wst, clnt->proto_version);
 	P9_DPRINTK(P9_DEBUG_9P, ">>> TWSTAT fid %d\n", fid->fid);
 	P9_DPRINTK(P9_DEBUG_9P,
 		"     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
diff --git a/net/9p/protocol.c b/net/9p/protocol.c
index fc70147c771..94f5a8f65e9 100644
--- a/net/9p/protocol.c
+++ b/net/9p/protocol.c
@@ -52,7 +52,7 @@
 #endif
 
 static int
-p9pdu_writef(struct p9_fcall *pdu, int optional, const char *fmt, ...);
+p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
 
 #ifdef CONFIG_NET_9P_DEBUG
 void
@@ -144,7 +144,8 @@ pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
 */
 
 static int
-p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
+p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
+	va_list ap)
 {
 	const char *ptr;
 	int errcode = 0;
@@ -194,7 +195,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				int16_t len;
 				int size;
 
-				errcode = p9pdu_readf(pdu, optional, "w", &len);
+				errcode = p9pdu_readf(pdu, proto_version,
+								"w", &len);
 				if (errcode)
 					break;
 
@@ -217,7 +219,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				struct p9_qid *qid =
 				    va_arg(ap, struct p9_qid *);
 
-				errcode = p9pdu_readf(pdu, optional, "bdq",
+				errcode = p9pdu_readf(pdu, proto_version, "bdq",
 						      &qid->type, &qid->version,
 						      &qid->path);
 			}
@@ -230,7 +232,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				stbuf->n_uid = stbuf->n_gid = stbuf->n_muid =
 									-1;
 				errcode =
-				    p9pdu_readf(pdu, optional,
+				    p9pdu_readf(pdu, proto_version,
 						"wwdQdddqssss?sddd",
 						&stbuf->size, &stbuf->type,
 						&stbuf->dev, &stbuf->qid,
@@ -250,7 +252,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				void **data = va_arg(ap, void **);
 
 				errcode =
-				    p9pdu_readf(pdu, optional, "d", count);
+				    p9pdu_readf(pdu, proto_version, "d", count);
 				if (!errcode) {
 					*count =
 					    MIN(*count,
@@ -263,8 +265,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				int16_t *nwname = va_arg(ap, int16_t *);
 				char ***wnames = va_arg(ap, char ***);
 
-				errcode =
-				    p9pdu_readf(pdu, optional, "w", nwname);
+				errcode = p9pdu_readf(pdu, proto_version,
+								"w", nwname);
 				if (!errcode) {
 					*wnames =
 					    kmalloc(sizeof(char *) * *nwname,
@@ -278,7 +280,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 
 					for (i = 0; i < *nwname; i++) {
 						errcode =
-						    p9pdu_readf(pdu, optional,
+						    p9pdu_readf(pdu,
+								proto_version,
 								"s",
 								&(*wnames)[i]);
 						if (errcode)
@@ -306,7 +309,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				*wqids = NULL;
 
 				errcode =
-				    p9pdu_readf(pdu, optional, "w", nwqid);
+				    p9pdu_readf(pdu, proto_version, "w", nwqid);
 				if (!errcode) {
 					*wqids =
 					    kmalloc(*nwqid *
@@ -321,7 +324,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 
 					for (i = 0; i < *nwqid; i++) {
 						errcode =
-						    p9pdu_readf(pdu, optional,
+						    p9pdu_readf(pdu,
+								proto_version,
 								"Q",
 								&(*wqids)[i]);
 						if (errcode)
@@ -336,7 +340,7 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 			}
 			break;
 		case '?':
-			if (!optional)
+			if (proto_version != p9_proto_2000u)
 				return 0;
 			break;
 		default:
@@ -352,7 +356,8 @@ p9pdu_vreadf(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 }
 
 int
-p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
+p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
+	va_list ap)
 {
 	const char *ptr;
 	int errcode = 0;
@@ -389,7 +394,8 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				if (sptr)
 					len = MIN(strlen(sptr), USHORT_MAX);
 
-				errcode = p9pdu_writef(pdu, optional, "w", len);
+				errcode = p9pdu_writef(pdu, proto_version,
+								"w", len);
 				if (!errcode && pdu_write(pdu, sptr, len))
 					errcode = -EFAULT;
 			}
@@ -398,7 +404,7 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				const struct p9_qid *qid =
 				    va_arg(ap, const struct p9_qid *);
 				errcode =
-				    p9pdu_writef(pdu, optional, "bdq",
+				    p9pdu_writef(pdu, proto_version, "bdq",
 						 qid->type, qid->version,
 						 qid->path);
 			} break;
@@ -406,7 +412,7 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				const struct p9_wstat *stbuf =
 				    va_arg(ap, const struct p9_wstat *);
 				errcode =
-				    p9pdu_writef(pdu, optional,
+				    p9pdu_writef(pdu, proto_version,
 						 "wwdQdddqssss?sddd",
 						 stbuf->size, stbuf->type,
 						 stbuf->dev, &stbuf->qid,
@@ -421,8 +427,8 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				int32_t count = va_arg(ap, int32_t);
 				const void *data = va_arg(ap, const void *);
 
-				errcode =
-				    p9pdu_writef(pdu, optional, "d", count);
+				errcode = p9pdu_writef(pdu, proto_version, "d",
+									count);
 				if (!errcode && pdu_write(pdu, data, count))
 					errcode = -EFAULT;
 			}
@@ -431,8 +437,8 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				int32_t count = va_arg(ap, int32_t);
 				const char __user *udata =
 						va_arg(ap, const void __user *);
-				errcode =
-				    p9pdu_writef(pdu, optional, "d", count);
+				errcode = p9pdu_writef(pdu, proto_version, "d",
+									count);
 				if (!errcode && pdu_write_u(pdu, udata, count))
 					errcode = -EFAULT;
 			}
@@ -441,14 +447,15 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				int16_t nwname = va_arg(ap, int);
 				const char **wnames = va_arg(ap, const char **);
 
-				errcode =
-				    p9pdu_writef(pdu, optional, "w", nwname);
+				errcode = p9pdu_writef(pdu, proto_version, "w",
+									nwname);
 				if (!errcode) {
 					int i;
 
 					for (i = 0; i < nwname; i++) {
 						errcode =
-						    p9pdu_writef(pdu, optional,
+						    p9pdu_writef(pdu,
+								proto_version,
 								 "s",
 								 wnames[i]);
 						if (errcode)
@@ -462,14 +469,15 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 				struct p9_qid *wqids =
 				    va_arg(ap, struct p9_qid *);
 
-				errcode =
-				    p9pdu_writef(pdu, optional, "w", nwqid);
+				errcode = p9pdu_writef(pdu, proto_version, "w",
+									nwqid);
 				if (!errcode) {
 					int i;
 
 					for (i = 0; i < nwqid; i++) {
 						errcode =
-						    p9pdu_writef(pdu, optional,
+						    p9pdu_writef(pdu,
+								proto_version,
 								 "Q",
 								 &wqids[i]);
 						if (errcode)
@@ -479,7 +487,7 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 			}
 			break;
 		case '?':
-			if (!optional)
+			if (proto_version != p9_proto_2000u)
 				return 0;
 			break;
 		default:
@@ -494,32 +502,32 @@ p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap)
 	return errcode;
 }
 
-int p9pdu_readf(struct p9_fcall *pdu, int optional, const char *fmt, ...)
+int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 {
 	va_list ap;
 	int ret;
 
 	va_start(ap, fmt);
-	ret = p9pdu_vreadf(pdu, optional, fmt, ap);
+	ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
 	va_end(ap);
 
 	return ret;
 }
 
 static int
-p9pdu_writef(struct p9_fcall *pdu, int optional, const char *fmt, ...)
+p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 {
 	va_list ap;
 	int ret;
 
 	va_start(ap, fmt);
-	ret = p9pdu_vwritef(pdu, optional, fmt, ap);
+	ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
 	va_end(ap);
 
 	return ret;
 }
 
-int p9stat_read(char *buf, int len, struct p9_wstat *st, int dotu)
+int p9stat_read(char *buf, int len, struct p9_wstat *st, int proto_version)
 {
 	struct p9_fcall fake_pdu;
 	int ret;
@@ -529,7 +537,7 @@ int p9stat_read(char *buf, int len, struct p9_wstat *st, int dotu)
 	fake_pdu.sdata = buf;
 	fake_pdu.offset = 0;
 
-	ret = p9pdu_readf(&fake_pdu, dotu, "S", st);
+	ret = p9pdu_readf(&fake_pdu, proto_version, "S", st);
 	if (ret) {
 		P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
 		p9pdu_dump(1, &fake_pdu);
diff --git a/net/9p/protocol.h b/net/9p/protocol.h
index ccde462e7ac..2431c0f38d5 100644
--- a/net/9p/protocol.h
+++ b/net/9p/protocol.h
@@ -25,9 +25,9 @@
  *
  */
 
-int
-p9pdu_vwritef(struct p9_fcall *pdu, int optional, const char *fmt, va_list ap);
-int p9pdu_readf(struct p9_fcall *pdu, int optional, const char *fmt, ...);
+int p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
+								va_list ap);
+int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type);
 int p9pdu_finalize(struct p9_fcall *pdu);
 void p9pdu_dump(int, struct p9_fcall *);
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index cb50f4ae5ee..afde1a89fbb 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -49,8 +49,6 @@
 
 /* a single mutex to manage channel initialization and attachment */
 static DEFINE_MUTEX(virtio_9p_lock);
-/* global which tracks highest initialized channel */
-static int chan_index;
 
 /**
  * struct virtio_chan - per-instance transport information
@@ -68,8 +66,7 @@ static int chan_index;
  *
  */
 
-static struct virtio_chan {
-	bool initialized;
+struct virtio_chan {
 	bool inuse;
 
 	spinlock_t lock;
@@ -80,7 +77,17 @@ static struct virtio_chan {
 
 	/* Scatterlist: can be too big for stack. */
 	struct scatterlist sg[VIRTQUEUE_NUM];
-} channels[MAX_9P_CHAN];
+
+	int tag_len;
+	/*
+	 * tag name to identify a mount Non-null terminated
+	 */
+	char *tag;
+
+	struct list_head chan_list;
+};
+
+static struct list_head virtio_chan_list;
 
 /* How many bytes left in this page. */
 static unsigned int rest_of_page(void *data)
@@ -213,30 +220,38 @@ p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
 	return 0;
 }
 
+static ssize_t p9_mount_tag_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct virtio_chan *chan;
+	struct virtio_device *vdev;
+
+	vdev = dev_to_virtio(dev);
+	chan = vdev->priv;
+
+	return snprintf(buf, chan->tag_len + 1, "%s", chan->tag);
+}
+
+static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL);
+
 /**
  * p9_virtio_probe - probe for existence of 9P virtio channels
  * @vdev: virtio device to probe
  *
- * This probes for existing virtio channels.  At present only
- * a single channel is in use, so in the future more work may need
- * to be done here.
+ * This probes for existing virtio channels.
  *
  */
 
 static int p9_virtio_probe(struct virtio_device *vdev)
 {
+	__u16 tag_len;
+	char *tag;
 	int err;
 	struct virtio_chan *chan;
-	int index;
 
-	mutex_lock(&virtio_9p_lock);
-	index = chan_index++;
-	chan = &channels[index];
-	mutex_unlock(&virtio_9p_lock);
-
-	if (chan_index > MAX_9P_CHAN) {
-		printk(KERN_ERR "9p: virtio: Maximum channels exceeded\n");
-		BUG();
+	chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL);
+	if (!chan) {
+		printk(KERN_ERR "9p: Failed to allocate virtio 9P channel\n");
 		err = -ENOMEM;
 		goto fail;
 	}
@@ -255,15 +270,37 @@ static int p9_virtio_probe(struct virtio_device *vdev)
 	sg_init_table(chan->sg, VIRTQUEUE_NUM);
 
 	chan->inuse = false;
-	chan->initialized = true;
+	if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) {
+		vdev->config->get(vdev,
+				offsetof(struct virtio_9p_config, tag_len),
+				&tag_len, sizeof(tag_len));
+	} else {
+		err = -EINVAL;
+		goto out_free_vq;
+	}
+	tag = kmalloc(tag_len, GFP_KERNEL);
+	if (!tag) {
+		err = -ENOMEM;
+		goto out_free_vq;
+	}
+	vdev->config->get(vdev, offsetof(struct virtio_9p_config, tag),
+			tag, tag_len);
+	chan->tag = tag;
+	chan->tag_len = tag_len;
+	err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
+	if (err) {
+		kfree(tag);
+		goto out_free_vq;
+	}
+	mutex_lock(&virtio_9p_lock);
+	list_add_tail(&chan->chan_list, &virtio_chan_list);
+	mutex_unlock(&virtio_9p_lock);
 	return 0;
 
 out_free_vq:
 	vdev->config->del_vqs(vdev);
+	kfree(chan);
 fail:
-	mutex_lock(&virtio_9p_lock);
-	chan_index--;
-	mutex_unlock(&virtio_9p_lock);
 	return err;
 }
 
@@ -280,35 +317,31 @@ fail:
  * We use a simple reference count mechanism to ensure that only a single
  * mount has a channel open at a time.
  *
- * Bugs: doesn't allow identification of a specific channel
- * to allocate, channels are allocated sequentially. This was
- * a pragmatic decision to get things rolling, but ideally some
- * way of identifying the channel to attach to would be nice
- * if we are going to support multiple channels.
- *
  */
 
 static int
 p9_virtio_create(struct p9_client *client, const char *devname, char *args)
 {
-	struct virtio_chan *chan = channels;
-	int index = 0;
+	struct virtio_chan *chan;
+	int ret = -ENOENT;
+	int found = 0;
 
 	mutex_lock(&virtio_9p_lock);
-	while (index < MAX_9P_CHAN) {
-		if (chan->initialized && !chan->inuse) {
-			chan->inuse = true;
-			break;
-		} else {
-			index++;
-			chan = &channels[index];
+	list_for_each_entry(chan, &virtio_chan_list, chan_list) {
+		if (!strncmp(devname, chan->tag, chan->tag_len)) {
+			if (!chan->inuse) {
+				chan->inuse = true;
+				found = 1;
+				break;
+			}
+			ret = -EBUSY;
 		}
 	}
 	mutex_unlock(&virtio_9p_lock);
 
-	if (index >= MAX_9P_CHAN) {
+	if (!found) {
 		printk(KERN_ERR "9p: no channels available\n");
-		return -ENODEV;
+		return ret;
 	}
 
 	client->trans = (void *)chan;
@@ -329,11 +362,15 @@ static void p9_virtio_remove(struct virtio_device *vdev)
 	struct virtio_chan *chan = vdev->priv;
 
 	BUG_ON(chan->inuse);
+	vdev->config->del_vqs(vdev);
+
+	mutex_lock(&virtio_9p_lock);
+	list_del(&chan->chan_list);
+	mutex_unlock(&virtio_9p_lock);
+	sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
+	kfree(chan->tag);
+	kfree(chan);
 
-	if (chan->initialized) {
-		vdev->config->del_vqs(vdev);
-		chan->initialized = false;
-	}
 }
 
 static struct virtio_device_id id_table[] = {
@@ -341,13 +378,19 @@ static struct virtio_device_id id_table[] = {
 	{ 0 },
 };
 
+static unsigned int features[] = {
+	VIRTIO_9P_MOUNT_TAG,
+};
+
 /* The standard "struct lguest_driver": */
 static struct virtio_driver p9_virtio_drv = {
-	.driver.name = 	KBUILD_MODNAME,
-	.driver.owner = THIS_MODULE,
-	.id_table =	id_table,
-	.probe = 	p9_virtio_probe,
-	.remove =	p9_virtio_remove,
+	.feature_table  = features,
+	.feature_table_size = ARRAY_SIZE(features),
+	.driver.name    = KBUILD_MODNAME,
+	.driver.owner	= THIS_MODULE,
+	.id_table	= id_table,
+	.probe		= p9_virtio_probe,
+	.remove		= p9_virtio_remove,
 };
 
 static struct p9_trans_module p9_virtio_trans = {
@@ -364,10 +407,7 @@ static struct p9_trans_module p9_virtio_trans = {
 /* The standard init function */
 static int __init p9_virtio_init(void)
 {
-	int count;
-
-	for (count = 0; count < MAX_9P_CHAN; count++)
-		channels[count].initialized = false;
+	INIT_LIST_HEAD(&virtio_chan_list);
 
 	v9fs_register_trans(&p9_virtio_trans);
 	return register_virtio_driver(&p9_virtio_drv);