From c4a11827b760ef8dcda26b5731d072b1d8fb7c81 Mon Sep 17 00:00:00 2001
From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>
Date: Fri, 2 Sep 2016 15:40:41 -0500
Subject: scsi: cxlflash: Fix context reference tracking on detach
Commit 888baf069f49 ("scsi: cxlflash: Add kref to context") introduced a
kref to the context. In particular, the detach routine was updated to
use the kref services for managing the removal and destruction of a
context.
As part of this change, the tracking mechanism internal to the detach
handler was refactored. This introduced a bug that can cause the
tracking state to be lost. This can lead to a situation where exclusive
access to a context is prematurely [and unknowingly] relinquished for
the executing thread.
To remedy, only update the tracking state when the kref operation
indicates the context was removed.
Fixes: 888baf069f49 ("scsi: cxlflash: Add kref to context")
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Acked-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---
drivers/scsi/cxlflash/superpipe.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
(limited to 'drivers/scsi')
diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c
index c91fe6fe8d08..9636970d9611 100644
--- a/drivers/scsi/cxlflash/superpipe.c
+++ b/drivers/scsi/cxlflash/superpipe.c
@@ -912,7 +912,8 @@ static int _cxlflash_disk_detach(struct scsi_device *sdev,
* Release the context reference and the sdev reference that
* bound this LUN to the context.
*/
- put_ctx = !kref_put(&ctxi->kref, remove_context);
+ if (kref_put(&ctxi->kref, remove_context))
+ put_ctx = false;
scsi_device_put(sdev);
out:
if (put_ctx)
--
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