On Tue, 2018-01-30 at 11:31 +0800, Ming Lei wrote: > Please take a look at drivers, when BLK_STS_RESOURCE is returned, who > will call blk_mq_delay_run_hw_queue() for drivers? As you know the SCSI and dm drivers in kernel v4.15 already call that function whenever necessary. > > > > > [ ... ] Later, you admitted you understood the patch wrong. [ ... ] > > > > That's nonsense. I never wrote that. > > Believe it or not, follows the link and your reply: > > https://marc.info/?l=dm-devel&m=151672694508389&w=2 > > > So what is wrong with this way? > > Sorry, I swapped BLK_STS_DEV_RESOURCE and BLK_STS_RESOURCE accidentally in my > > reply. What I meant is that changing a blk_mq_delay_run_hw_queue() call followed > > by return BLK_STS_RESOURCE into BLK_STS_DEV_RESOURCE is wrong and introduces a > > race condition in code where there was no race condition. That meant that I made a mistake (typo) while typing the reply and nothing else. Bart.