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From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>
To: linux-scsi@vger.kernel.org,
	James.Bottomley@HansenPartnership.com, nab@linux-iscsi.org,
	brking@linux.vnet.ibm.com, imunsie@au1.ibm.com,
	dja@ozlabs.au.ibm.com, andrew.donnellan@au1.ibm.com
Cc: mikey@neuling.org, linuxppc-dev@lists.ozlabs.org,
	"Manoj N. Kumar" <manoj@linux.vnet.ibm.com>
Subject: [PATCH v2 28/30] cxlflash: Fix to prevent stale AFU RRQ
Date: Wed, 16 Sep 2015 12:05:29 -0500	[thread overview]
Message-ID: <1442423129-42373-1-git-send-email-mrochs@linux.vnet.ibm.com> (raw)

Following an adapter reset, the AFU RRQ that resides in host memory
holds stale data. This can lead to a condition where the RRQ interrupt
handler tries to process stale entries and/or endlessly loops due to an
out of sync generation bit.

To fix, the AFU RRQ in host memory needs to be cleared after each reset.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
---
 drivers/scsi/cxlflash/main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index a5b45ed..0487fac 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -1609,6 +1609,9 @@ static int start_afu(struct cxlflash_cfg *cfg)
 
 	init_pcr(cfg);
 
+	/* After an AFU reset, RRQ entries are stale, clear them */
+	memset(&afu->rrq_entry, 0, sizeof(afu->rrq_entry));
+
 	/* Initialize RRQ pointers */
 	afu->hrrq_start = &afu->rrq_entry[0];
 	afu->hrrq_end = &afu->rrq_entry[NUM_RRQ_ENTRY - 1];
-- 
2.1.0

             reply	other threads:[~2015-09-16 17:06 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-16 17:05 Matthew R. Ochs [this message]
  -- strict thread matches above, loose matches on Subject: below --
2015-09-16 21:23 [PATCH v2 00/30] cxlflash: Miscellaneous bug fixes and corrections Matthew R. Ochs
2015-09-16 21:32 ` [PATCH v2 28/30] cxlflash: Fix to prevent stale AFU RRQ Matthew R. Ochs
2015-09-23 19:18   ` Brian King

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