Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9p: fix put_data error handling
  9p: use an IS_ERR test rather than a NULL test
  9p: introduce missing kfree
  9p-trans_fd: fix and clean up module init/exit paths
  9p-trans_fd: don't do fs segment mangling in p9_fd_poll()
  9p-trans_fd: clean up p9_conn_create()
  9p-trans_fd: fix trans_fd::p9_conn_destroy()
  9p: implement proper trans module refcounting and unregistration

5 files changed, 118 insertions, 96 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 2ffe40c..10e3203 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -75,7 +75,6 @@ static int parse_opts(char *opts, struct p9_client *clnt)
 	int option;
 	int ret = 0;
 
-	clnt->trans_mod = v9fs_default_trans();
 	clnt->dotu = 1;
 	clnt->msize = 8192;
 
@@ -108,7 +107,7 @@ static int parse_opts(char *opts, struct p9_client *clnt)
 			clnt->msize = option;
 			break;
 		case Opt_trans:
-			clnt->trans_mod = v9fs_match_trans(&args[0]);
+			clnt->trans_mod = v9fs_get_trans_by_name(&args[0]);
 			break;
 		case Opt_legacy:
 			clnt->dotu = 0;
@@ -117,6 +116,10 @@ static int parse_opts(char *opts, struct p9_client *clnt)
 			continue;
 		}
 	}
+
+	if (!clnt->trans_mod)
+		clnt->trans_mod = v9fs_get_default_trans();
+
 	kfree(options);
 	return ret;
 }
@@ -150,6 +153,7 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
 	if (!clnt)
 		return ERR_PTR(-ENOMEM);
 
+	clnt->trans_mod = NULL;
 	clnt->trans = NULL;
 	spin_lock_init(&clnt->lock);
 	INIT_LIST_HEAD(&clnt->fidlist);
@@ -235,6 +239,8 @@ void p9_client_destroy(struct p9_client *clnt)
 		clnt->trans = NULL;
 	}
 
+	v9fs_put_trans(clnt->trans_mod);
+
 	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist)
 		p9_fid_destroy(fid);
 
diff --git a/net/9p/conv.c b/net/9p/conv.c
index 4454720..5ad3a3b 100644
--- a/net/9p/conv.c
+++ b/net/9p/conv.c
@@ -451,8 +451,10 @@ p9_put_data(struct cbuf *bufp, const char *data, int count,
 		   unsigned char **pdata)
 {
 	*pdata = buf_alloc(bufp, count);
+	if (*pdata == NULL)
+		return -ENOMEM;
 	memmove(*pdata, data, count);
-	return count;
+	return 0;
 }
 
 static int
@@ -460,6 +462,8 @@ p9_put_user_data(struct cbuf *bufp, const char __user *data, int count,
 		   unsigned char **pdata)
 {
 	*pdata = buf_alloc(bufp, count);
+	if (*pdata == NULL)
+		return -ENOMEM;
 	return copy_from_user(*pdata, data, count);
 }
 
diff --git a/net/9p/mod.c b/net/9p/mod.c
index bdee1fb..1084feb 100644
--- a/net/9p/mod.c
+++ b/net/9p/mod.c
@@ -31,6 +31,7 @@
 #include <linux/parser.h>
 #include <net/9p/transport.h>
 #include <linux/list.h>
+#include <linux/spinlock.h>
 
 #ifdef CONFIG_NET_9P_DEBUG
 unsigned int p9_debug_level = 0;	/* feature-rific global debug level  */
@@ -44,8 +45,8 @@ MODULE_PARM_DESC(debug, "9P debugging level");
  *
  */
 
+static DEFINE_SPINLOCK(v9fs_trans_lock);
 static LIST_HEAD(v9fs_trans_list);
-static struct p9_trans_module *v9fs_default_transport;
 
 /**
  * v9fs_register_trans - register a new transport with 9p
@@ -54,48 +55,87 @@ static struct p9_trans_module *v9fs_default_transport;
  */
 void v9fs_register_trans(struct p9_trans_module *m)
 {
+	spin_lock(&v9fs_trans_lock);
 	list_add_tail(&m->list, &v9fs_trans_list);
-	if (m->def)
-		v9fs_default_transport = m;
+	spin_unlock(&v9fs_trans_lock);
 }
 EXPORT_SYMBOL(v9fs_register_trans);
 
 /**
- * v9fs_match_trans - match transport versus registered transports
+ * v9fs_unregister_trans - unregister a 9p transport
+ * @m: the transport to remove
+ *
+ */
+void v9fs_unregister_trans(struct p9_trans_module *m)
+{
+	spin_lock(&v9fs_trans_lock);
+	list_del_init(&m->list);
+	spin_unlock(&v9fs_trans_lock);
+}
+EXPORT_SYMBOL(v9fs_unregister_trans);
+
+/**
+ * v9fs_get_trans_by_name - get transport with the matching name
  * @name: string identifying transport
  *
  */
-struct p9_trans_module *v9fs_match_trans(const substring_t *name)
+struct p9_trans_module *v9fs_get_trans_by_name(const substring_t *name)
 {
-	struct list_head *p;
-	struct p9_trans_module *t = NULL;
-
-	list_for_each(p, &v9fs_trans_list) {
-		t = list_entry(p, struct p9_trans_module, list);
-		if (strncmp(t->name, name->from, name->to-name->from) == 0)
-			return t;
-	}
-	return NULL;
+	struct p9_trans_module *t, *found = NULL;
+
+	spin_lock(&v9fs_trans_lock);
+
+	list_for_each_entry(t, &v9fs_trans_list, list)
+		if (strncmp(t->name, name->from, name->to-name->from) == 0 &&
+		    try_module_get(t->owner)) {
+			found = t;
+			break;
+		}
+
+	spin_unlock(&v9fs_trans_lock);
+	return found;
 }
-EXPORT_SYMBOL(v9fs_match_trans);
+EXPORT_SYMBOL(v9fs_get_trans_by_name);
 
 /**
- * v9fs_default_trans - returns pointer to default transport
+ * v9fs_get_default_trans - get the default transport
  *
  */
 
-struct p9_trans_module *v9fs_default_trans(void)
+struct p9_trans_module *v9fs_get_default_trans(void)
 {
-	if (v9fs_default_transport)
-		return v9fs_default_transport;
-	else if (!list_empty(&v9fs_trans_list))
-		return list_first_entry(&v9fs_trans_list,
-					struct p9_trans_module, list);
-	else
-		return NULL;
+	struct p9_trans_module *t, *found = NULL;
+
+	spin_lock(&v9fs_trans_lock);
+
+	list_for_each_entry(t, &v9fs_trans_list, list)
+		if (t->def && try_module_get(t->owner)) {
+			found = t;
+			break;
+		}
+
+	if (!found)
+		list_for_each_entry(t, &v9fs_trans_list, list)
+			if (try_module_get(t->owner)) {
+				found = t;
+				break;
+			}
+
+	spin_unlock(&v9fs_trans_lock);
+	return found;
 }
-EXPORT_SYMBOL(v9fs_default_trans);
+EXPORT_SYMBOL(v9fs_get_default_trans);
 
+/**
+ * v9fs_put_trans - put trans
+ * @m: transport to put
+ *
+ */
+void v9fs_put_trans(struct p9_trans_module *m)
+{
+	if (m)
+		module_put(m->owner);
+}
 
 /**
  * v9fs_init - Initialize module
@@ -120,6 +160,8 @@ static int __init init_p9(void)
 static void __exit exit_p9(void)
 {
 	printk(KERN_INFO "Unloading 9P2000 support\n");
+
+	p9_trans_fd_exit();
 }
 
 module_init(init_p9)
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index cdf137a..d652baf 100644
--- a/net/9p/trans_fd.c
+++ b/net/9p/trans_fd.c
@@ -151,7 +151,6 @@ struct p9_mux_poll_task {
  * @trans: reference to transport instance for this connection
  * @tagpool: id accounting for transactions
  * @err: error state
- * @equeue: event wait_q (?)
  * @req_list: accounting for requests which have been sent
  * @unsent_req_list: accounting for requests that haven't been sent
  * @rcall: current response &p9_fcall structure
@@ -178,7 +177,6 @@ struct p9_conn {
 	struct p9_trans *trans;
 	struct p9_idpool *tagpool;
 	int err;
-	wait_queue_head_t equeue;
 	struct list_head req_list;
 	struct list_head unsent_req_list;
 	struct p9_fcall *rcall;
@@ -240,22 +238,6 @@ static int p9_conn_rpcnb(struct p9_conn *m, struct p9_fcall *tc,
 
 static void p9_conn_cancel(struct p9_conn *m, int err);
 
-static int p9_mux_global_init(void)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++)
-		p9_mux_poll_tasks[i].task = NULL;
-
-	p9_mux_wq = create_workqueue("v9fs");
-	if (!p9_mux_wq) {
-		printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
-		return -ENOMEM;
-	}
-
-	return 0;
-}
-
 static u16 p9_mux_get_tag(struct p9_conn *m)
 {
 	int tag;
@@ -409,11 +391,11 @@ static void p9_mux_poll_stop(struct p9_conn *m)
 static struct p9_conn *p9_conn_create(struct p9_trans *trans)
 {
 	int i, n;
-	struct p9_conn *m, *mtmp;
+	struct p9_conn *m;
 
 	P9_DPRINTK(P9_DEBUG_MUX, "transport %p msize %d\n", trans,
 								trans->msize);
-	m = kmalloc(sizeof(struct p9_conn), GFP_KERNEL);
+	m = kzalloc(sizeof(struct p9_conn), GFP_KERNEL);
 	if (!m)
 		return ERR_PTR(-ENOMEM);
 
@@ -424,25 +406,14 @@ static struct p9_conn *p9_conn_create(struct p9_trans *trans)
 	m->trans = trans;
 	m->tagpool = p9_idpool_create();
 	if (IS_ERR(m->tagpool)) {
-		mtmp = ERR_PTR(-ENOMEM);
 		kfree(m);
-		return mtmp;
+		return ERR_PTR(-ENOMEM);
 	}
 
-	m->err = 0;
-	init_waitqueue_head(&m->equeue);
 	INIT_LIST_HEAD(&m->req_list);
 	INIT_LIST_HEAD(&m->unsent_req_list);
-	m->rcall = NULL;
-	m->rpos = 0;
-	m->rbuf = NULL;
-	m->wpos = m->wsize = 0;
-	m->wbuf = NULL;
 	INIT_WORK(&m->rq, p9_read_work);
 	INIT_WORK(&m->wq, p9_write_work);
-	m->wsched = 0;
-	memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
-	m->poll_task = NULL;
 	n = p9_mux_poll_start(m);
 	if (n) {
 		kfree(m);
@@ -463,10 +434,8 @@ static struct p9_conn *p9_conn_create(struct p9_trans *trans)
 	for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
 		if (IS_ERR(m->poll_waddr[i])) {
 			p9_mux_poll_stop(m);
-			mtmp = (void *)m->poll_waddr;	/* the error code */
 			kfree(m);
-			m = mtmp;
-			break;
+			return (void *)m->poll_waddr;	/* the error code */
 		}
 	}
 
@@ -483,18 +452,13 @@ static void p9_conn_destroy(struct p9_conn *m)
 {
 	P9_DPRINTK(P9_DEBUG_MUX, "mux %p prev %p next %p\n", m,
 		m->mux_list.prev, m->mux_list.next);
-	p9_conn_cancel(m, -ECONNRESET);
-
-	if (!list_empty(&m->req_list)) {
-		/* wait until all processes waiting on this session exit */
-		P9_DPRINTK(P9_DEBUG_MUX,
-			"mux %p waiting for empty request queue\n", m);
-		wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
-		P9_DPRINTK(P9_DEBUG_MUX, "mux %p request queue empty: %d\n", m,
-			list_empty(&m->req_list));
-	}
 
 	p9_mux_poll_stop(m);
+	cancel_work_sync(&m->rq);
+	cancel_work_sync(&m->wq);
+
+	p9_conn_cancel(m, -ECONNRESET);
+
 	m->trans = NULL;
 	p9_idpool_destroy(m->tagpool);
 	kfree(m);
@@ -840,8 +804,6 @@ static void p9_read_work(struct work_struct *work)
 					(*req->cb) (req, req->cba);
 				else
 					kfree(req->rcall);
-
-				wake_up(&m->equeue);
 			}
 		} else {
 			if (err >= 0 && rcall->id != P9_RFLUSH)
@@ -908,8 +870,10 @@ static struct p9_req *p9_send_request(struct p9_conn *m,
 	else
 		n = p9_mux_get_tag(m);
 
-	if (n < 0)
+	if (n < 0) {
+		kfree(req);
 		return ERR_PTR(-ENOMEM);
+	}
 
 	p9_set_tag(tc, n);
 
@@ -984,8 +948,6 @@ static void p9_mux_flush_cb(struct p9_req *freq, void *a)
 			(*req->cb) (req, req->cba);
 		else
 			kfree(req->rcall);
-
-		wake_up(&m->equeue);
 	}
 
 	kfree(freq->tcall);
@@ -1191,8 +1153,6 @@ void p9_conn_cancel(struct p9_conn *m, int err)
 		else
 			kfree(req->rcall);
 	}
-
-	wake_up(&m->equeue);
 }
 
 /**
@@ -1370,7 +1330,6 @@ p9_fd_poll(struct p9_trans *trans, struct poll_table_struct *pt)
 {
 	int ret, n;
 	struct p9_trans_fd *ts = NULL;
-	mm_segment_t oldfs;
 
 	if (trans && trans->status == Connected)
 		ts = trans->priv;
@@ -1384,24 +1343,17 @@ p9_fd_poll(struct p9_trans *trans, struct poll_table_struct *pt)
 	if (!ts->wr->f_op || !ts->wr->f_op->poll)
 		return -EIO;
 
-	oldfs = get_fs();
-	set_fs(get_ds());
-
 	ret = ts->rd->f_op->poll(ts->rd, pt);
 	if (ret < 0)
-		goto end;
+		return ret;
 
 	if (ts->rd != ts->wr) {
 		n = ts->wr->f_op->poll(ts->wr, pt);
-		if (n < 0) {
-			ret = n;
-			goto end;
-		}
+		if (n < 0)
+			return n;
 		ret = (ret & ~POLLOUT) | (n & ~POLLIN);
 	}
 
-end:
-	set_fs(oldfs);
 	return ret;
 }
 
@@ -1629,6 +1581,7 @@ static struct p9_trans_module p9_tcp_trans = {
 	.maxsize = MAX_SOCK_BUF,
 	.def = 1,
 	.create = p9_trans_create_tcp,
+	.owner = THIS_MODULE,
 };
 
 static struct p9_trans_module p9_unix_trans = {
@@ -1636,6 +1589,7 @@ static struct p9_trans_module p9_unix_trans = {
 	.maxsize = MAX_SOCK_BUF,
 	.def = 0,
 	.create = p9_trans_create_unix,
+	.owner = THIS_MODULE,
 };
 
 static struct p9_trans_module p9_fd_trans = {
@@ -1643,14 +1597,20 @@ static struct p9_trans_module p9_fd_trans = {
 	.maxsize = MAX_SOCK_BUF,
 	.def = 0,
 	.create = p9_trans_create_fd,
+	.owner = THIS_MODULE,
 };
 
 int p9_trans_fd_init(void)
 {
-	int ret = p9_mux_global_init();
-	if (ret) {
-		printk(KERN_WARNING "9p: starting mux failed\n");
-		return ret;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++)
+		p9_mux_poll_tasks[i].task = NULL;
+
+	p9_mux_wq = create_workqueue("v9fs");
+	if (!p9_mux_wq) {
+		printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
+		return -ENOMEM;
 	}
 
 	v9fs_register_trans(&p9_tcp_trans);
@@ -1659,4 +1619,12 @@ int p9_trans_fd_init(void)
 
 	return 0;
 }
-EXPORT_SYMBOL(p9_trans_fd_init);
+
+void p9_trans_fd_exit(void)
+{
+	v9fs_unregister_trans(&p9_tcp_trans);
+	v9fs_unregister_trans(&p9_unix_trans);
+	v9fs_unregister_trans(&p9_fd_trans);
+
+	destroy_workqueue(p9_mux_wq);
+}
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 42adc05..94912e0 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -528,6 +528,7 @@ static struct p9_trans_module p9_virtio_trans = {
 	.create = p9_virtio_create,
 	.maxsize = PAGE_SIZE*16,
 	.def = 0,
+	.owner = THIS_MODULE,
 };
 
 /* The standard init function */
@@ -545,6 +546,7 @@ static int __init p9_virtio_init(void)
 static void __exit p9_virtio_cleanup(void)
 {
 	unregister_virtio_driver(&p9_virtio_drv);
+	v9fs_unregister_trans(&p9_virtio_trans);
 }
 
 module_init(p9_virtio_init);