RDMA/cxgb3: Serialize calls to CQ's comp_handler
iw_cxgb3 has a potential problem where a CQ's comp_handler can get
called simultaneously from different places in iw_cxgb3 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.
Such problem was reported by Parav Pandit <Parav.Pandit@Emulex.Com>
for iw_cxgb4 driver. 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.
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/cxgb3/iwch_ev.c b/drivers/infiniband/hw/cxgb3/iwch_ev.c
index 71e0d84..abcc9e7 100644
--- a/drivers/infiniband/hw/cxgb3/iwch_ev.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_ev.c
@@ -46,6 +46,7 @@
struct ib_event event;
struct iwch_qp_attributes attrs;
struct iwch_qp *qhp;
+ unsigned long flag;
spin_lock(&rnicp->lock);
qhp = get_qhp(rnicp, CQE_QPID(rsp_msg->cqe));
@@ -94,7 +95,9 @@
if (qhp->ibqp.event_handler)
(*qhp->ibqp.event_handler)(&event, qhp->ibqp.qp_context);
+ spin_lock_irqsave(&chp->comp_handler_lock, flag);
(*chp->ibcq.comp_handler)(&chp->ibcq, chp->ibcq.cq_context);
+ spin_unlock_irqrestore(&chp->comp_handler_lock, flag);
if (atomic_dec_and_test(&qhp->refcnt))
wake_up(&qhp->wait);
@@ -107,6 +110,7 @@
struct iwch_cq *chp;
struct iwch_qp *qhp;
u32 cqid = RSPQ_CQID(rsp_msg);
+ unsigned long flag;
rnicp = (struct iwch_dev *) rdev_p->ulp;
spin_lock(&rnicp->lock);
@@ -170,7 +174,9 @@
*/
if (qhp->ep && SQ_TYPE(rsp_msg->cqe))
dst_confirm(qhp->ep->dst);
+ spin_lock_irqsave(&chp->comp_handler_lock, flag);
(*chp->ibcq.comp_handler)(&chp->ibcq, chp->ibcq.cq_context);
+ spin_unlock_irqrestore(&chp->comp_handler_lock, flag);
break;
case TPT_ERR_STAG: