* [PATCH] sg: reset 'res_in_use' after unlinking reserved array
@ 2017-04-24 8:26 Hannes Reinecke
2017-04-24 8:32 ` Johannes Thumshirn
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Hannes Reinecke @ 2017-04-24 8:26 UTC (permalink / raw)
To: Martin K. Petersen
Cc: Christoph Hellwig, James Bottomley, Johannes Thumshirn,
linux-scsi, Hannes Reinecke, Hannes Reinecke
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.
Fixes: 1bc0eb0 ("scsi: sg: protect accesses to 'reserved' page array")
Signed-off-by: Hannes Reinecke <hare@suse.com>
---
drivers/scsi/sg.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 8147147..06503c1 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -2056,6 +2056,8 @@ static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned lon
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 *
--
1.8.5.6
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] sg: reset 'res_in_use' after unlinking reserved array
2017-04-24 8:26 [PATCH] sg: reset 'res_in_use' after unlinking reserved array Hannes Reinecke
@ 2017-04-24 8:32 ` Johannes Thumshirn
2017-04-24 15:30 ` Christoph Hellwig
2017-04-24 22:20 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Johannes Thumshirn @ 2017-04-24 8:32 UTC (permalink / raw)
To: Hannes Reinecke
Cc: Martin K. Petersen, Christoph Hellwig, James Bottomley,
Johannes Thumshirn, linux-scsi, Hannes Reinecke
On Mon, Apr 24, 2017 at 10:26:36AM +0200, Hannes Reinecke wrote:
> 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.
>
> Fixes: 1bc0eb0 ("scsi: sg: protect accesses to 'reserved' page array")
> Signed-off-by: Hannes Reinecke <hare@suse.com>
> ---
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sg: reset 'res_in_use' after unlinking reserved array
2017-04-24 8:26 [PATCH] sg: reset 'res_in_use' after unlinking reserved array Hannes Reinecke
2017-04-24 8:32 ` Johannes Thumshirn
@ 2017-04-24 15:30 ` Christoph Hellwig
2017-04-24 22:20 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Christoph Hellwig @ 2017-04-24 15:30 UTC (permalink / raw)
To: Hannes Reinecke
Cc: Martin K. Petersen, Christoph Hellwig, James Bottomley,
Johannes Thumshirn, linux-scsi, Hannes Reinecke
Looks fine,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sg: reset 'res_in_use' after unlinking reserved array
2017-04-24 8:26 [PATCH] sg: reset 'res_in_use' after unlinking reserved array Hannes Reinecke
2017-04-24 8:32 ` Johannes Thumshirn
2017-04-24 15:30 ` Christoph Hellwig
@ 2017-04-24 22:20 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Martin K. Petersen @ 2017-04-24 22:20 UTC (permalink / raw)
To: Hannes Reinecke
Cc: Martin K. Petersen, Christoph Hellwig, James Bottomley,
Johannes Thumshirn, linux-scsi, Hannes Reinecke
Hannes,
> 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.
Applied to 4.12/scsi-queue.
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-04-24 22:21 UTC | newest]
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2017-04-24 8:26 [PATCH] sg: reset 'res_in_use' after unlinking reserved array Hannes Reinecke
2017-04-24 8:32 ` Johannes Thumshirn
2017-04-24 15:30 ` Christoph Hellwig
2017-04-24 22:20 ` Martin K. Petersen
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