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

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>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 8147147df2f4..06503c10ea27 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -2056,6 +2056,8 @@ sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
         req_schp->page_order = 0;
         req_schp->sglist_len = 0;
         srp->res_used = 0;
+        /* Called without mutex lock to avoid deadlock */
+        sfp->res_in_use = 0;
 }
 
 static Sg_request *