[DLM] Make sock_sem into a mutex

Now that there can be multiple dlm_recv threads running we need to prevent two
recvs running for the same connection - it's unlikely but it can happen and it
causes message corruption.

Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 22 insertions, 22 deletions

diff --git a/fs/dlm/lowcomms-tcp.c b/fs/dlm/lowcomms-tcp.c
index 8e6a76cf1805..18ade44287e7 100644
--- a/fs/dlm/lowcomms-tcp.c
+++ b/fs/dlm/lowcomms-tcp.c
@@ -96,7 +96,7 @@ static bool cbuf_empty(struct cbuf *cb)
 struct connection {
         struct socket *sock;    /* NULL if not connected */
         uint32_t nodeid;        /* So we know who we are in the list */
-        struct rw_semaphore sock_sem; /* Stop connect races */
+        struct mutex sock_mutex;
         unsigned long flags;    /* bit 1,2 = We are on the read/write lists */
 #define CF_READ_PENDING 1
 #define CF_WRITE_PENDING 2
@@ -171,7 +171,7 @@ static struct connection *nodeid2con(int nodeid, gfp_t allocation)
                         goto finish;
 
                 con->nodeid = nodeid;
-                init_rwsem(&con->sock_sem);
+                mutex_init(&con->sock_mutex);
                 INIT_LIST_HEAD(&con->writequeue);
                 spin_lock_init(&con->writequeue_lock);
                 INIT_WORK(&con->swork, process_send_sockets);
@@ -247,7 +247,7 @@ static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
 /* Close a remote connection and tidy up */
 static void close_connection(struct connection *con, bool and_other)
 {
-        down_write(&con->sock_sem);
+        mutex_lock(&con->sock_mutex);
 
         if (con->sock) {
                 sock_release(con->sock);
@@ -262,7 +262,7 @@ static void close_connection(struct connection *con, bool and_other)
                 con->rx_page = NULL;
         }
         con->retries = 0;
-        up_write(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
 }
 
 /* Data received from remote end */
@@ -276,7 +276,7 @@ static int receive_from_sock(struct connection *con)
         int r;
         int call_again_soon = 0;
 
-        down_read(&con->sock_sem);
+        mutex_lock(&con->sock_mutex);
 
         if (con->sock == NULL)
                 goto out;
@@ -355,17 +355,17 @@ static int receive_from_sock(struct connection *con)
 out:
         if (call_again_soon)
                 goto out_resched;
-        up_read(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
         return 0;
 
 out_resched:
         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
                 queue_work(recv_workqueue, &con->rwork);
-        up_read(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
         return -EAGAIN;
 
 out_close:
-        up_read(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
         if (ret != -EAGAIN && !test_bit(CF_IS_OTHERCON, &con->flags)) {
                 close_connection(con, false);
                 /* Reconnect when there is something to send */
@@ -391,7 +391,7 @@ static int accept_from_sock(struct connection *con)
         if (result < 0)
                 return -ENOMEM;
 
-        down_read_nested(&con->sock_sem, 0);
+        mutex_lock_nested(&con->sock_mutex, 0);
 
         result = -ENOTCONN;
         if (con->sock == NULL)
@@ -417,7 +417,7 @@ static int accept_from_sock(struct connection *con)
         if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
                 printk("dlm: connect from non cluster node\n");
                 sock_release(newsock);
-                up_read(&con->sock_sem);
+                mutex_unlock(&con->sock_mutex);
                 return -1;
         }
 
@@ -434,7 +434,7 @@ static int accept_from_sock(struct connection *con)
                 result = -ENOMEM;
                 goto accept_err;
         }
-        down_write_nested(&newcon->sock_sem, 1);
+        mutex_lock_nested(&newcon->sock_mutex, 1);
         if (newcon->sock) {
                 struct connection *othercon = newcon->othercon;
 
@@ -442,13 +442,13 @@ static int accept_from_sock(struct connection *con)
                         othercon = kmem_cache_zalloc(con_cache, GFP_KERNEL);
                         if (!othercon) {
                                 printk("dlm: failed to allocate incoming socket\n");
-                                up_write(&newcon->sock_sem);
+                                mutex_unlock(&newcon->sock_mutex);
                                 result = -ENOMEM;
                                 goto accept_err;
                         }
                         othercon->nodeid = nodeid;
                         othercon->rx_action = receive_from_sock;
-                        init_rwsem(&othercon->sock_sem);
+                        mutex_init(&othercon->sock_mutex);
                         INIT_WORK(&othercon->swork, process_send_sockets);
                         INIT_WORK(&othercon->rwork, process_recv_sockets);
                         set_bit(CF_IS_OTHERCON, &othercon->flags);
@@ -466,7 +466,7 @@ static int accept_from_sock(struct connection *con)
                 addcon = newcon;
         }
 
-        up_write(&newcon->sock_sem);
+        mutex_unlock(&newcon->sock_mutex);
 
         /*
          * Add it to the active queue in case we got data
@@ -475,12 +475,12 @@ static int accept_from_sock(struct connection *con)
          */
         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
                 queue_work(recv_workqueue, &addcon->rwork);
-        up_read(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
 
         return 0;
 
 accept_err:
-        up_read(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
         sock_release(newsock);
 
         if (result != -EAGAIN)
@@ -501,7 +501,7 @@ static void connect_to_sock(struct connection *con)
                 return;
         }
 
-        down_write(&con->sock_sem);
+        mutex_lock(&con->sock_mutex);
         if (con->retries++ > MAX_CONNECT_RETRIES)
                 goto out;
 
@@ -553,7 +553,7 @@ out_err:
                 result = 0;
         }
 out:
-        up_write(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
         return;
 }
 
@@ -757,7 +757,7 @@ static void send_to_sock(struct connection *con)
         struct writequeue_entry *e;
         int len, offset;
 
-        down_read(&con->sock_sem);
+        mutex_lock(&con->sock_mutex);
         if (con->sock == NULL)
                 goto out_connect;
 
@@ -803,17 +803,17 @@ static void send_to_sock(struct connection *con)
         }
         spin_unlock(&con->writequeue_lock);
 out:
-        up_read(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
         return;
 
 send_error:
-        up_read(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
         close_connection(con, false);
         lowcomms_connect_sock(con);
         return;
 
 out_connect:
-        up_read(&con->sock_sem);
+        mutex_unlock(&con->sock_mutex);
         connect_to_sock(con);
         return;
 }