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Commit 2aee309d authored by Mike Marciniszyn's avatar Mike Marciniszyn Committed by Doug Ledford
Browse files

IB/hfi1: Fix deadlock with txreq allocation slow path 



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.

Cc: Stable <stable@vger.kernel.org> # 4.6+
Reviewed-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarMike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: default avatarDennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 34d351f8

drivers/infiniband/hw/hfi1/verbs_txreq.c

+1 −3
Original line number Diff line number Diff line
@@ -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;

}

drivers/infiniband/hw/hfi1/verbs_txreq.h

+1 −0
Original line number Diff line number Diff line
@@ -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;