[PATCH v3 18/18] ibmvfc: drop host lock when completing commands in CRQ
From: Tyrel Datwyler <tyreld@linux.ibm.com>
Date: 2020-12-03 02:10:49
Also in:
linux-scsi, lkml
Subsystem:
ibm power virtual fc device drivers, linux for powerpc (32-bit and 64-bit), scsi subsystem, the rest · Maintainers:
Tyrel Datwyler, Madhavan Srinivasan, "James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds
The legacy CRQ holds the host lock the even while completing commands. This presents a problem when in legacy single queue mode and nr_hw_queues is greater than one since calling scsi_done() introduces the potential for deadlock. If nr_hw_queues is greater than one drop the hostlock in the legacy CRQ path when completing a command. Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com> --- drivers/scsi/ibmvscsi/ibmvfc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index e499599662ec..e2200bdff2be 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c@@ -2969,6 +2969,7 @@ static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost) { long rc; struct ibmvfc_event *evt = (struct ibmvfc_event *)be64_to_cpu(crq->ioba); + unsigned long flags; switch (crq->valid) { case IBMVFC_CRQ_INIT_RSP:
@@ -3039,7 +3040,12 @@ static void ibmvfc_handle_crq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost) del_timer(&evt->timer); list_del(&evt->queue); ibmvfc_trc_end(evt); - evt->done(evt); + if (nr_scsi_hw_queues > 1) { + spin_unlock_irqrestore(vhost->host->host_lock, flags); + evt->done(evt); + spin_lock_irqsave(vhost->host->host_lock, flags); + } else + evt->done(evt); } /**
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2.27.0