4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hannes Reinecke <hare@xxxxxxx>
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@xxxxxxxx>
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Todd Poynor <toddpoynor@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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 *