RDMA/rtrs-clt: Check if the queue_depth has changed during a reconnection

The queue_depth is a module parameter for rtrs_server. It is used on the
client side to determing the queue_depth of the request queue for the RNBD
virtual block device.

During a reconnection event for an already mapped device, in case the
rtrs_server module queue_depth has changed, fail the reconnect attempt.

Also stop further auto reconnection attempts. A manual reconnect via
sysfs has to be triggerred.

Fixes: 6a98d71daea18 ("RDMA/rtrs: client: main functionality")
Link: https://lore.kernel.org/r/20210528113018.52290-20-jinpu.wang@ionos.com
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 88a1c93..e4a23c4 100644 (file)
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -1780,7 +1780,19 @@ static int rtrs_rdma_conn_established(struct rtrs_clt_con *con,
                                  queue_depth);
                        return -ECONNRESET;
                }
-               if (!sess->rbufs || sess->queue_depth < queue_depth) {
+               if (sess->queue_depth > 0 && queue_depth != sess->queue_depth) {
+                       rtrs_err(clt, "Error: queue depth changed\n");
+
+                       /*
+                        * Stop any more reconnection attempts
+                        */
+                       sess->reconnect_attempts = -1;
+                       rtrs_err(clt,
+                               "Disabling auto-reconnect. Trigger a manual reconnect after issue is resolved\n");
+                       return -ECONNRESET;
+               }
+
+               if (!sess->rbufs) {
                        kfree(sess->rbufs);
                        sess->rbufs = kcalloc(queue_depth, sizeof(*sess->rbufs),
                                              GFP_KERNEL);
@@ -1794,7 +1806,7 @@ static int rtrs_rdma_conn_established(struct rtrs_clt_con *con,
                sess->chunk_size = sess->max_io_size + sess->max_hdr_size;
 
                /*
-                * Global queue depth and IO size is always a minimum.
+                * Global IO size is always a minimum.
                 * If while a reconnection server sends us a value a bit
                 * higher - client does not care and uses cached minimum.
                 *
@@ -1802,8 +1814,7 @@ static int rtrs_rdma_conn_established(struct rtrs_clt_con *con,
                 * connections in parallel, use lock.
                 */
                mutex_lock(&clt->paths_mutex);
-               clt->queue_depth = min_not_zero(sess->queue_depth,
-                                               clt->queue_depth);
+               clt->queue_depth = sess->queue_depth;
                clt->max_io_size = min_not_zero(sess->max_io_size,
                                                clt->max_io_size);
                mutex_unlock(&clt->paths_mutex);