[PATCH 4.14 019/118] iw_cxgb4: only clear the ARMED bit if a notification is needed

From: Greg Kroah-Hartman
Date: Mon Jan 15 2018 - 08:24:07 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>

commit 335ebf6fa35ca1c59b73f76fad19b249d3550e86 upstream.

In __flush_qp(), the CQ ARMED bit was being cleared regardless of
whether any notification is actually needed. This resulted in the iser
termination logic getting stuck in ib_drain_sq() because the CQ was not
marked ARMED and thus the drain CQE notification wasn't triggered.

This new bug was exposed when this commit was merged:

commit cbb40fadd31c ("iw_cxgb4: only call the cq comp_handler when the
cq is armed")

Signed-off-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/infiniband/hw/cxgb4/qp.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/hw/cxgb4/qp.c
+++ b/drivers/infiniband/hw/cxgb4/qp.c
@@ -1301,21 +1301,21 @@ static void __flush_qp(struct c4iw_qp *q
spin_unlock_irqrestore(&rchp->lock, flag);

if (schp == rchp) {
- if (t4_clear_cq_armed(&rchp->cq) &&
- (rq_flushed || sq_flushed)) {
+ if ((rq_flushed || sq_flushed) &&
+ t4_clear_cq_armed(&rchp->cq)) {
spin_lock_irqsave(&rchp->comp_handler_lock, flag);
(*rchp->ibcq.comp_handler)(&rchp->ibcq,
rchp->ibcq.cq_context);
spin_unlock_irqrestore(&rchp->comp_handler_lock, flag);
}
} else {
- if (t4_clear_cq_armed(&rchp->cq) && rq_flushed) {
+ if (rq_flushed && t4_clear_cq_armed(&rchp->cq)) {
spin_lock_irqsave(&rchp->comp_handler_lock, flag);
(*rchp->ibcq.comp_handler)(&rchp->ibcq,
rchp->ibcq.cq_context);
spin_unlock_irqrestore(&rchp->comp_handler_lock, flag);
}
- if (t4_clear_cq_armed(&schp->cq) && sq_flushed) {
+ if (sq_flushed && t4_clear_cq_armed(&schp->cq)) {
spin_lock_irqsave(&schp->comp_handler_lock, flag);
(*schp->ibcq.comp_handler)(&schp->ibcq,
schp->ibcq.cq_context);