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authorSteve Wise <swise@opengridcomputing.com>2017-11-09 18:21:26 +0300
committerDoug Ledford <dledford@redhat.com>2017-11-14 00:59:22 +0300
commitbc52e9ca74b9a395897bb640c6671b2cbf716032 (patch)
treebf286e85ae7597e6b6bbd744491ea49631904952 /drivers/infiniband
parentcbb40fadd31c6bbc59104e58ac95c6ef492d038b (diff)
downloadlinux-bc52e9ca74b9a395897bb640c6671b2cbf716032.tar.xz
iw_cxgb4: atomically flush the qp
__flush_qp() has a race condition where during the flush operation, the qp lock is released allowing another thread to possibly post a WR, which corrupts the queue state, possibly causing crashes. The lock was released to preserve the cq/qp locking hierarchy of cq first, then qp. However releasing the qp lock is not necessary; both RQ and SQ CQ locks can be acquired first, followed by the qp lock, and then the RQ and SQ flushing can be done w/o unlocking. Signed-off-by: Steve Wise <swise@opengridcomputing.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'drivers/infiniband')
-rw-r--r--drivers/infiniband/hw/cxgb4/qp.c19
1 files changed, 11 insertions, 8 deletions
diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c
index fefc5fed1778..5ee7fe433136 100644
--- a/drivers/infiniband/hw/cxgb4/qp.c
+++ b/drivers/infiniband/hw/cxgb4/qp.c
@@ -1255,31 +1255,34 @@ static void __flush_qp(struct c4iw_qp *qhp, struct c4iw_cq *rchp,
pr_debug("qhp %p rchp %p schp %p\n", qhp, rchp, schp);
- /* locking hierarchy: cq lock first, then qp lock. */
+ /* locking hierarchy: cqs lock first, then qp lock. */
spin_lock_irqsave(&rchp->lock, flag);
+ if (schp != rchp)
+ spin_lock(&schp->lock);
spin_lock(&qhp->lock);
if (qhp->wq.flushed) {
spin_unlock(&qhp->lock);
+ if (schp != rchp)
+ spin_unlock(&schp->lock);
spin_unlock_irqrestore(&rchp->lock, flag);
return;
}
qhp->wq.flushed = 1;
+ t4_set_wq_in_error(&qhp->wq);
c4iw_flush_hw_cq(rchp);
c4iw_count_rcqes(&rchp->cq, &qhp->wq, &count);
rq_flushed = c4iw_flush_rq(&qhp->wq, &rchp->cq, count);
- spin_unlock(&qhp->lock);
- spin_unlock_irqrestore(&rchp->lock, flag);
- /* locking hierarchy: cq lock first, then qp lock. */
- spin_lock_irqsave(&schp->lock, flag);
- spin_lock(&qhp->lock);
if (schp != rchp)
c4iw_flush_hw_cq(schp);
sq_flushed = c4iw_flush_sq(qhp);
+
spin_unlock(&qhp->lock);
- spin_unlock_irqrestore(&schp->lock, flag);
+ if (schp != rchp)
+ spin_unlock(&schp->lock);
+ spin_unlock_irqrestore(&rchp->lock, flag);
if (schp == rchp) {
if (t4_clear_cq_armed(&rchp->cq) &&
@@ -1313,8 +1316,8 @@ static void flush_qp(struct c4iw_qp *qhp)
rchp = to_c4iw_cq(qhp->ibqp.recv_cq);
schp = to_c4iw_cq(qhp->ibqp.send_cq);
- t4_set_wq_in_error(&qhp->wq);
if (qhp->ibqp.uobject) {
+ t4_set_wq_in_error(&qhp->wq);
t4_set_cq_in_error(&rchp->cq);
spin_lock_irqsave(&rchp->comp_handler_lock, flag);
(*rchp->ibcq.comp_handler)(&rchp->ibcq, rchp->ibcq.cq_context);