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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Sreekanth Reddy <sreekanth.reddy@broadcom.com>,
        Tomas Henzl <thenzl@redhat.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 219/633] scsi: mpt3sas: Fix sync irqs
Date:   Tue, 27 Oct 2020 14:49:22 +0100
Message-Id: <20201027135532.959168099@linuxfoundation.org>
In-Reply-To: <20201027135522.655719020@linuxfoundation.org>
References: <20201027135522.655719020@linuxfoundation.org>
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From: Tomas Henzl <thenzl@redhat.com>

[ Upstream commit 45181eab8ba79ed7a41b549f00500c0093828521 ]

_base_process_reply_queue() called from _base_interrupt() may schedule a
new irq poll. Fix this by calling synchronize_irq() first.

Also ensure that enable_irq() is called only when necessary to avoid
"Unbalanced enable for IRQ..." errors.

Link: https://lore.kernel.org/r/20200910142126.8147-1-thenzl@redhat.com
Fixes: 320e77acb327 ("scsi: mpt3sas: Irq poll to avoid CPU hard lockups")
Acked-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/mpt3sas/mpt3sas_base.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index a85c9672c6ea3..a67749c8f4ab3 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -1808,18 +1808,22 @@ mpt3sas_base_sync_reply_irqs(struct MPT3SAS_ADAPTER *ioc)
 		/* TMs are on msix_index == 0 */
 		if (reply_q->msix_index == 0)
 			continue;
+		synchronize_irq(pci_irq_vector(ioc->pdev, reply_q->msix_index));
 		if (reply_q->irq_poll_scheduled) {
 			/* Calling irq_poll_disable will wait for any pending
 			 * callbacks to have completed.
 			 */
 			irq_poll_disable(&reply_q->irqpoll);
 			irq_poll_enable(&reply_q->irqpoll);
-			reply_q->irq_poll_scheduled = false;
-			reply_q->irq_line_enable = true;
-			enable_irq(reply_q->os_irq);
-			continue;
+			/* check how the scheduled poll has ended,
+			 * clean up only if necessary
+			 */
+			if (reply_q->irq_poll_scheduled) {
+				reply_q->irq_poll_scheduled = false;
+				reply_q->irq_line_enable = true;
+				enable_irq(reply_q->os_irq);
+			}
 		}
-		synchronize_irq(pci_irq_vector(ioc->pdev, reply_q->msix_index));
 	}
 }
 
-- 
2.25.1