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>

diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c
index c91fe6fe8d088323de2aa3833462ee6890d9c061..9636970d96116107be34ed08201bd099bc0603f6 100644 (file)
--- 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)