[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>

diff --git a/fs/dlm/lowcomms-tcp.c b/fs/dlm/lowcomms-tcp.c
index 8e6a76c..18ade44 100644 (file)
--- 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;
 }