Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle

From: Bart Van Assche
Date: Thu Jan 18 2018 - 15:58:59 EST


On Thu, 2018-01-18 at 15:48 -0500, Mike Snitzer wrote:
> For Bart's test the underlying scsi-mq driver is what is regularly
> hitting this case in __blk_mq_try_issue_directly():
>
> if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))

Hello Mike,

That code path is not the code path that triggered the lockups that I reported
during the past days. These lockups were all triggered by incorrect handling of
.queue_rq() returning BLK_STS_RESOURCE.

Bart.