Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 14/16] scsi: sg: reset res_in_use after unlinking reserved array | Date | Thu, 31 Aug 2017 17:44:07 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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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 @@ -2052,6 +2052,8 @@ 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 *
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