On Tue, Jan 22 2019 at 3:20am -0500,
Ming Lei <ming.lei@xxxxxxxxxx> wrote:
> Except for blk_queue_split(), bio_split() is used for splitting bio too,
> then the remained bio is often resubmit to queue via generic_make_request().
> So the same queue enter recursion exits in this case too. Unfortunatley
> commit cd4a4ae4683dc2 doesn't help this case.
>
> This patch covers the above case by setting BIO_QUEUE_ENTERED before calling
> q->make_request_fn.
>
> In theory the per-bio flag is used to simulate one stack variable, it is
> just fine to clear it after q->make_request_fn is returned. Especially
> the same bio can't be submitted from another context.
>
> Fixes: cd4a4ae4683dc2 ("block: don't use blocking queue entered for recursive bio submits")
> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Cc: NeilBrown <neilb@xxxxxxxx>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Looks good, I'll drop my DM patch that set/cleared BIO_QUEUE_ENTERED.
Jens, you OK with picking this up for 5.0-rc?
Reviewed-by: Mike Snitzer <snitzer@xxxxxxxxxx>
