Patch "scsi: sg: reset 'res_in_use' after unlinking reserved array" has been added to the 4.9-stable tree

Patch "scsi: sg: reset 'res_in_use' after unlinking reserved array" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    scsi: sg: reset 'res_in_use' after unlinking reserved array

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     scsi-sg-reset-res_in_use-after-unlinking-reserved-array.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e791ce27c3f6a1d3c746fd6a8f8e36c9540ec6f9 Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare@suse.de>
Date: Mon, 24 Apr 2017 10:26:36 +0200
Subject: scsi: sg: reset 'res_in_use' after unlinking reserved array

From: Hannes Reinecke <hare@suse.de>

commit e791ce27c3f6a1d3c746fd6a8f8e36c9540ec6f9 upstream.

Once the reserved page array is unused we can reset the 'res_in_use'
state; here we can do a lazy update without holding the mutex as we only
need to check against concurrent access, not concurrent release.

[mkp: checkpatch]

Fixes: 1bc0eb044615 ("scsi: sg: protect accesses to 'reserved' page array")
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/scsi/sg.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -2042,6 +2042,8 @@ sg_unlink_reserve(Sg_fd * sfp, Sg_reques
 	req_schp->sglist_len = 0;
 	sfp->save_scat_len = 0;
 	srp->res_used = 0;
+	/* Called without mutex lock to avoid deadlock */
+	sfp->res_in_use = 0;
 }
 
 static Sg_request *


Patches currently in stable-queue which might be from hare@suse.de are

queue-4.9/scsi-sg-protect-accesses-to-reserved-page-array.patch
queue-4.9/scsi-sg-reset-res_in_use-after-unlinking-reserved-array.patch