From: Hannes Reinecke <hare@xxxxxxx> This patch has been added to the v4.1 stable tree. If you have any objections, please let us know. =============== [ 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@xxxxxxxx> Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> --- drivers/scsi/sg.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 7a06417e2bf5..c1232cb6b85f 100644 --- 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 * -- 2.11.0