Messages in this thread | | | Subject | Re: [PATCH V2 8/8] blk-mq: remove blk_mq_tagset_busy_iter | From | "jianchao.wang" <> | Date | Mon, 25 Mar 2019 15:37:04 +0800 |
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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 <jianchao.w.wang@oracle.com> >> --- >> 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
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