drbd: Introduce a "lockless" variant of drbd_send_protocoll()

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index e6e4f4e..44f7726 100644 (file)
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1051,6 +1051,7 @@ extern int drbd_send(struct drbd_tconn *tconn, struct socket *sock,
 extern int drbd_send_all(struct drbd_tconn *, struct socket *, void *, size_t,
                         unsigned);
 
+extern int __drbd_send_protocol(struct drbd_tconn *tconn);
 extern int drbd_send_protocol(struct drbd_tconn *tconn);
 extern int drbd_send_uuids(struct drbd_conf *mdev);
 extern int drbd_send_uuids_skip_initial_sync(struct drbd_conf *mdev);

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 7472235..3cb2af6 100644 (file)
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -757,14 +757,24 @@ static unsigned int prepare_header(struct drbd_tconn *tconn, int vnr,
                return prepare_header80(buffer, cmd, size);
 }
 
+static void *__conn_prepare_command(struct drbd_tconn *tconn,
+                                   struct drbd_socket *sock)
+{
+       if (!sock->socket)
+               return NULL;
+       return sock->sbuf + drbd_header_size(tconn);
+}
+
 void *conn_prepare_command(struct drbd_tconn *tconn, struct drbd_socket *sock)
 {
+       void *p;
+
        mutex_lock(&sock->mutex);
-       if (!sock->socket) {
+       p = __conn_prepare_command(tconn, sock);
+       if (!p)
                mutex_unlock(&sock->mutex);
-               return NULL;
-       }
-       return sock->sbuf + drbd_header_size(tconn);
+
+       return p;
 }
 
 void *drbd_prepare_command(struct drbd_conf *mdev, struct drbd_socket *sock)
@@ -798,13 +808,20 @@ static int __send_command(struct drbd_tconn *tconn, int vnr,
        return err;
 }
 
+static int __conn_send_command(struct drbd_tconn *tconn, struct drbd_socket *sock,
+                              enum drbd_packet cmd, unsigned int header_size,
+                              void *data, unsigned int size)
+{
+       return __send_command(tconn, 0, sock, cmd, header_size, data, size);
+}
+
 int conn_send_command(struct drbd_tconn *tconn, struct drbd_socket *sock,
                      enum drbd_packet cmd, unsigned int header_size,
                      void *data, unsigned int size)
 {
        int err;
 
-       err = __send_command(tconn, 0, sock, cmd, header_size, data, size);
+       err = __conn_send_command(tconn, sock, cmd, header_size, data, size);
        mutex_unlock(&sock->mutex);
        return err;
 }
@@ -893,7 +910,7 @@ int drbd_send_sync_param(struct drbd_conf *mdev)
        return drbd_send_command(mdev, sock, cmd, size, NULL, 0);
 }
 
-int drbd_send_protocol(struct drbd_tconn *tconn)
+int __drbd_send_protocol(struct drbd_tconn *tconn)
 {
        struct drbd_socket *sock;
        struct p_protocol *p;
@@ -901,7 +918,7 @@ int drbd_send_protocol(struct drbd_tconn *tconn)
        int size, cf;
 
        sock = &tconn->data;
-       p = conn_prepare_command(tconn, sock);
+       p = __conn_prepare_command(tconn, sock);
        if (!p)
                return -EIO;
 
@@ -935,7 +952,18 @@ int drbd_send_protocol(struct drbd_tconn *tconn)
                strcpy(p->integrity_alg, nc->integrity_alg);
        rcu_read_unlock();
 
-       return conn_send_command(tconn, sock, P_PROTOCOL, size, NULL, 0);
+       return __conn_send_command(tconn, sock, P_PROTOCOL, size, NULL, 0);
+}
+
+int drbd_send_protocol(struct drbd_tconn *tconn)
+{
+       int err;
+
+       mutex_lock(&tconn->data.mutex);
+       err = __drbd_send_protocol(tconn);
+       mutex_unlock(&tconn->data.mutex);
+
+       return err;
 }
 
 int _drbd_send_uuids(struct drbd_conf *mdev, u64 uuid_flags)