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

[ Upstream commit e791ce27c3f6a1d3c746fd6a8f8e36c9540ec6f9 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 7a06417e2bf5f2da6f11e30547c5b66971650fb2..c1232cb6b85f3221678dcf7dc1870e81418664f3 100644 (file)
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -2046,6 +2046,8 @@ sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
        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 *