On Tue, Jul 30, 2019 at 08:43:59AM +0800, Ming Lei wrote:
On Thu, Jul 25, 2019 at 10:04:58AM +0800, Ming Lei wrote:
Hi,
When one request is dispatched to LLD via dm-rq, if the result is BLK_STS_*RESOURCE, dm-rq will free the request. However, LLD may allocate private data for this request, so this way will cause memory leak.
Add .cleanup_rq() callback and implement it in SCSI for fixing the issue, since SCSI is the only driver which allocates private requst data in .queue_rq() path.
Another use case of this callback is to free the request and re-submit bios during cpu hotplug when the hctx is dead, see the following link:
https://lore.kernel.org/linux-block/f122e8f2-5ede-2d83-9ca0-bc713ce66d01@hua...
V4:
- add more commit log on the new .cleanup_rq callback, as suggested by Mike
V3:
- run .cleanup_rq() from dm-rq because this issue is dm-rq specific,
and even in future it should be still very unusual to free request in this way. If we call .cleanup_rq() in generic rq free code(fast path), cost will be introduced unnecessarily, also we have to consider related race.
V2:
- run .cleanup_rq() in blk_mq_free_request(), as suggested by Mike
Ming Lei (2): blk-mq: add callback of .cleanup_rq scsi: implement .cleanup_rq callback
drivers/md/dm-rq.c | 1 + drivers/scsi/scsi_lib.c | 13 +++++++++++++ include/linux/blk-mq.h | 13 +++++++++++++ 3 files changed, 27 insertions(+)
Cc: Ewan D. Milne emilne@redhat.com Cc: Bart Van Assche bvanassche@acm.org Cc: Hannes Reinecke hare@suse.com Cc: Christoph Hellwig hch@lst.de Cc: Mike Snitzer snitzer@redhat.com Cc: dm-devel@redhat.com Cc: stable@vger.kernel.org Fixes: 396eaf21ee17 ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback")
Hello Jens & guys,
Ping on this fix.
Hi Jens,
Could you make the patcheset merged for 5.4? And it has been verified that big memory leak issue can be fixed by this patchset.
thanks, Ming