From mboxrd@z Thu Jan 1 00:00:00 1970 From: jianchao.w.wang@oracle.com (jianchao.wang) Date: Mon, 25 Mar 2019 15:37:04 +0800 Subject: [PATCH V2 8/8] blk-mq: remove blk_mq_tagset_busy_iter In-Reply-To: <47fe0e2a-f427-0e3e-e15b-a9e2bffb502f@suse.de> References: <1553492318-1810-1-git-send-email-jianchao.w.wang@oracle.com> <1553492318-1810-9-git-send-email-jianchao.w.wang@oracle.com> <47fe0e2a-f427-0e3e-e15b-a9e2bffb502f@suse.de> Message-ID: Hi Hannes On 3/25/19 3:18 PM, Hannes Reinecke wrote: > On 3/25/19 6:38 AM, Jianchao Wang wrote: >> As nobody uses blk_mq_tagset_busy_iter, remove it. >> >> Signed-off-by: Jianchao Wang >> --- >> ? block/blk-mq-tag.c???? | 95 -------------------------------------------------- >> ? include/linux/blk-mq.h |? 2 -- >> ? 2 files changed, 97 deletions(-) >> > Please, don't. > > I'm currently implementing reserved commands for SCSI and reworking the SCSI error handling where I rely on this interface quite heavily. blk_mq_tagset_busy_iter could access some stale requests which maybe freed due to io scheduler switching, request_queue cleanup (shared tagset) when there is someone submits io and gets driver tag. When io scheduler attached, even quiesce request_queue won't work. If this patchset is accepted, blk_mq_tagset_busy_iter could be replaced with blk_mq_queue_inflight_tag_iter which needs to be invoked by every request_queue that shares the tagset. Please go ahead your work. Thanks Jianchao > > Cheers, > > Hannes