RDMA/cxgb4: Serialize calls to CQ's comp_handler
Commit 01e7da6ba53c ("RDMA/cxgb4: Make sure flush CQ entries are
collected on connection close") introduced a potential problem where a
CQ's comp_handler can get called simultaneously from different places
in the iw_cxgb4 driver. This does not comply with
Documentation/infiniband/core_locking.txt, which states that at a
given point of time, there should be only one callback per CQ should
be active.
This problem was reported by Parav Pandit <Parav.Pandit@Emulex.Com>.
Based on discussion between Parav Pandit and Steve Wise, this patch
fixes the above problem by serializing the calls to a CQ's
comp_handler using a spin_lock.
Reported-by: Parav Pandit <Parav.Pandit@Emulex.Com>
Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/cxgb4/cq.c b/drivers/infiniband/hw/cxgb4/cq.c
index 901c5fb..f35a935 100644
--- a/drivers/infiniband/hw/cxgb4/cq.c
+++ b/drivers/infiniband/hw/cxgb4/cq.c
@@ -818,6 +818,7 @@
chp->cq.size--; /* status page */
chp->ibcq.cqe = entries - 2;
spin_lock_init(&chp->lock);
+ spin_lock_init(&chp->comp_handler_lock);
atomic_set(&chp->refcnt, 1);
init_waitqueue_head(&chp->wait);
ret = insert_handle(rhp, &rhp->cqidr, chp, chp->cq.cqid);