On Mon, Jan 24, 2022 at 02:15:16PM +0100, Christoph Hellwig wrote: > On Sat, Jan 22, 2022 at 07:10:50PM +0800, Ming Lei wrote: > > In scsi_disk_release() request queue is frozen for clearing > > disk->private_data, and there can't be any FS IO issued to > > this queue, and only private passthrough request will be handled, so > > force unfreezing queue into atomic mode. > > > > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> > > --- > > drivers/scsi/sd.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > > index 0e73c3f2f381..27f04c860f00 100644 > > --- a/drivers/scsi/sd.c > > +++ b/drivers/scsi/sd.c > > @@ -3670,7 +3670,7 @@ static void scsi_disk_release(struct device *dev) > > * in case multiple processes open a /dev/sd... node concurrently. > > */ > > blk_mq_freeze_queue(q); > > - blk_mq_unfreeze_queue(q); > > + __blk_mq_unfreeze_queue(q, true); > > I think the right thing here is to drop the freeze/unfreeze pair. > Now that del_gendisk properly freezes the queue, we don't need this > protection as the issue that Bart fixed with it can't happen any more. As you see, the last patch removes freeze/unfreeze pair in del_gendisk(), which looks not very useful: it can't drain IO on bio based driver, and del_gendisk() is supposed to provide consistent behavior for both request and bio based driver. Thanks, Ming
