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

8 files changed, 127 insertions, 100 deletions

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index c95295c65045..e83aa5ebe861 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -626,8 +626,7 @@ static struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
         return NULL;
 
 error:
-        if (fid)
-                p9_client_clunk(fid);
+        p9_client_clunk(fid);
 
         return ERR_PTR(result);
 }
diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index b3d3e27c6299..c3626c0ba9d3 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -596,4 +596,5 @@ int p9_idpool_check(int id, struct p9_idpool *p);
 int p9_error_init(void);
 int p9_errstr2errno(char *, int);
 int p9_trans_fd_init(void);
+void p9_trans_fd_exit(void);
 #endif /* NET_9P_H */
diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index 0db3a4038dc0..3ca737120a90 100644
--- a/include/net/9p/transport.h
+++ b/include/net/9p/transport.h
@@ -26,6 +26,8 @@
 #ifndef NET_9P_TRANSPORT_H
 #define NET_9P_TRANSPORT_H
 
+#include <linux/module.h>
+
 /**
  * enum p9_trans_status - different states of underlying transports
  * @Connected: transport is connected and healthy
@@ -91,9 +93,12 @@ struct p9_trans_module {
         int maxsize;            /* max message size of transport */
         int def;                /* this transport should be default */
         struct p9_trans * (*create)(const char *, char *, int, unsigned char);
+        struct module *owner;
 };
 
 void v9fs_register_trans(struct p9_trans_module *m);
-struct p9_trans_module *v9fs_match_trans(const substring_t *name);
-struct p9_trans_module *v9fs_default_trans(void);
+void v9fs_unregister_trans(struct p9_trans_module *m);
+struct p9_trans_module *v9fs_get_trans_by_name(const substring_t *name);
+struct p9_trans_module *v9fs_get_default_trans(void);
+void v9fs_put_trans(struct p9_trans_module *m);
 #endif /* NET_9P_TRANSPORT_H */
diff --git a/net/9p/client.c b/net/9p/client.c
index 2ffe40cf2f01..10e320307ec0 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 44547201f5bc..5ad3a3bd73b2 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 bdee1fb7cc62..1084feb24cb0 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 cdf137af7adc..d652baf5ff91 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 42adc052b149..94912e077a55 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);