diff mbox

IB/hfi1: Fix deadlock with txreq allocation slow path

Message ID 20160720211254.15373.67532.stgit@phlsvslse11.ph.intel.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Marciniszyn, Mike July 20, 2016, 9:12 p.m. UTC 
A failure in the get_txreq() inline will result in a
slow path retry using __get_txreq().

__get_txreq() attempts to procure the qp s_lock, which
is already held in all callers.

Fix by deleting the s_lock maintenance in __get_txreq()
and add sparse syntax hooks to future proof the code.

Ported from upstream 2aee309d3e01 to 4.6 stable.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
---
 drivers/staging/rdma/hfi1/verbs_txreq.c |    4 +---
 drivers/staging/rdma/hfi1/verbs_txreq.h |    1 +
 2 files changed, 2 insertions(+), 3 deletions(-)


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diff mbox

Patch

diff --git a/drivers/staging/rdma/hfi1/verbs_txreq.c b/drivers/staging/rdma/hfi1/verbs_txreq.c
index bc95c41..d8fb056 100644
--- a/drivers/staging/rdma/hfi1/verbs_txreq.c
+++ b/drivers/staging/rdma/hfi1/verbs_txreq.c
@@ -92,11 +92,10 @@  void hfi1_put_txreq(struct verbs_txreq *tx)
 
 struct verbs_txreq *__get_txreq(struct hfi1_ibdev *dev,
 				struct rvt_qp *qp)
+	__must_hold(&qp->s_lock)
 {
 	struct verbs_txreq *tx = ERR_PTR(-EBUSY);
-	unsigned long flags;
 
-	spin_lock_irqsave(&qp->s_lock, flags);
 	write_seqlock(&dev->iowait_lock);
 	if (ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK) {
 		struct hfi1_qp_priv *priv;
@@ -116,7 +115,6 @@  struct verbs_txreq *__get_txreq(struct hfi1_ibdev *dev,
 	}
 out:
 	write_sequnlock(&dev->iowait_lock);
-	spin_unlock_irqrestore(&qp->s_lock, flags);
 	return tx;
 }
 
diff --git a/drivers/staging/rdma/hfi1/verbs_txreq.h b/drivers/staging/rdma/hfi1/verbs_txreq.h
index 1cf69b2..a1d6e08 100644
--- a/drivers/staging/rdma/hfi1/verbs_txreq.h
+++ b/drivers/staging/rdma/hfi1/verbs_txreq.h
@@ -73,6 +73,7 @@  struct verbs_txreq *__get_txreq(struct hfi1_ibdev *dev,
 
 static inline struct verbs_txreq *get_txreq(struct hfi1_ibdev *dev,
 					    struct rvt_qp *qp)
+	__must_hold(&qp->slock)
 {
 	struct verbs_txreq *tx;
 	struct hfi1_qp_priv *priv = qp->priv;