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Commit 7049de65 authored by Mike Marciniszyn's avatar Mike Marciniszyn Committed by Doug Ledford
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IB/hfi1: Fix hard lockup due to not using save/restore spin lock 



Commit b9b06cb6
("IB/hfi1: Fix missing lock/unlock in verbs drain callback")
added a spin lock.

Unfortunately, the new lock code can be called from a base
level interrupt state, and an interrupt that can get stacked
will attempt to get the same lock.

Fix by using the flag save/restore spin lock variation.

Cc: stable@vger.kernel.org # 4.6+
Reviewed-by: default avatarSebastian Sanchez <sebastian.sanchez@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 bdd8a98c

drivers/infiniband/hw/hfi1/qp.c

+3 −2
Original line number Diff line number Diff line
@@ -512,6 +512,7 @@ static void iowait_wakeup(struct iowait *wait, int reason) 
static void iowait_sdma_drained(struct iowait *wait)

{

	struct rvt_qp *qp = iowait_to_qp(wait);

	unsigned long flags;



	/*

	 * This happens when the send engine notes
@@ -519,12 +520,12 @@ static void iowait_sdma_drained(struct iowait *wait) 
	 * do the flush work until that QP's

	 * sdma work has finished.

	 */

	spin_lock(&qp->s_lock);

	spin_lock_irqsave(&qp->s_lock, flags);

	if (qp->s_flags & RVT_S_WAIT_DMA) {

		qp->s_flags &= ~RVT_S_WAIT_DMA;

		hfi1_schedule_send(qp);

	}

	spin_unlock(&qp->s_lock);

	spin_unlock_irqrestore(&qp->s_lock, flags);

}



/**