[PATCH] mpt3sas: Fix timeouts observed while reenabling IRQ

[Sreekanth Reddy <sreekanth.reddy@broadcom.com>]

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While reenabling the IRQ after irq poll there may be small time
window where HBA firmware has posted some replies and raise the
interrupts but driver has not received the interrupts. So we may
observe IO timeouts as the driver has not processed the replies
as interrupts got missed while reenabling the IRQ.

So, to fix this issue, the driver has to go for one more
round of processing the reply descriptors from reply descriptor
post queue after enabling the IRQ.

Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Reported-by: Tomas Henzl <thenzl@redhat.com>
---
 drivers/scsi/mpt3sas/mpt3sas_base.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index b096917..a0ab44d 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -1740,6 +1740,13 @@ _base_irqpoll(struct irq_poll *irqpoll, int budget)
 		reply_q->irq_poll_scheduled = false;
 		reply_q->irq_line_enable = true;
 		enable_irq(reply_q->os_irq);
+		/*
+		 * Go for one more round of processing the
+		 * reply descriptor post queue incase if HBA
+		 * Firmware has posted some reply descriptors
+		 * while reenabling the IRQ.
+		 */
+		_base_process_reply_queue(reply_q);
 	}
 
 	return num_entries;
-- 
2.18.4


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