Peek at the CQ after arming it so that we can return a hint.
This avoids missed completions due to a race between posting
CQEs and arming the CQ.
For example, CM teardown waits on MAD requests to complete with
ib_cq_poll_work(). Without this fix, the last completion might be
left on the CQ, hanging the kthread doing the teardown.
The console backtraces look like this:
[ 4199.911284] Call Trace:
[ 4199.911401] [<ffffffff9657fe95>] schedule+0x35/0x80
[ 4199.911556] [<ffffffff965830df>] schedule_timeout+0x22f/0x2c0
[ 4199.911727] [<ffffffff9657f7a8>] ? __schedule+0x368/0xa20
[ 4199.911891] [<ffffffff96580903>] wait_for_completion+0xb3/0x130
[ 4199.912067] [<ffffffff960a17e0>] ? wake_up_q+0x70/0x70
[ 4199.912243] [<ffffffffc074a06d>] cm_destroy_id+0x13d/0x450 [ib_cm]
[ 4199.912422] [<ffffffff961615d5>] ? printk+0x57/0x73
[ 4199.912578] [<ffffffffc074a390>] ib_destroy_cm_id+0x10/0x20 [ib_cm]
[ 4199.912759] [<ffffffffc076098c>] rdma_destroy_id+0xac/0x340 [rdma_cm]
[ 4199.912941] [<ffffffffc076f2cc>] 0xffffffffc076f2cc
Signed-off-by: Andrew Boyer <andrew.boyer@xxxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_verbs.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 19841c8..de39b0a 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -1007,11 +1007,19 @@ static int rxe_peek_cq(struct ib_cq *ibcq, int wc_cnt)
static int rxe_req_notify_cq(struct ib_cq *ibcq, enum ib_cq_notify_flags flags)
{
struct rxe_cq *cq = to_rcq(ibcq);
+ unsigned long irq_flags;
+ int ret = 0;
+ spin_lock_irqsave(&cq->cq_lock, irq_flags);
if (cq->notify != IB_CQ_NEXT_COMP)
cq->notify = flags & IB_CQ_SOLICITED_MASK;
- return 0;
+ if ((flags & IB_CQ_REPORT_MISSED_EVENTS) && !queue_empty(cq->queue))
+ ret = 1;
+
+ spin_unlock_irqrestore(&cq->cq_lock, irq_flags);
+
+ return ret;
}
static struct ib_mr *rxe_get_dma_mr(struct ib_pd *ibpd, int access)
--
1.8.3.1
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
