Re: [PATCH V4 0/2] block/scsi/dm-rq: fix leak of request private data in dm-mpath

On 7/24/19 7:04 PM, 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...

Applied for 5.4, thanks.