Yeah looks good. Reviewed-by: Jesse Barnes <jsbarnes@xxxxxxxxxx> A further change (just for readability) might be to factor out these "don't trigger hangcheck" waits from here and blk_execute_rq() into a small helper with a descriptive name. Thanks, Jesse On Thu, Feb 20, 2020 at 5:05 AM Ming Lei <ming.lei@xxxxxxxxxx> wrote: > > submit_bio_wait() can be called from ioctl(BLKSECDISCARD), which > may take long time to complete, as Salman mentioned, 4K BLKSECDISCARD > takes up to 100 second on some devices. Also any block I/O operation > that occurs after the BLKSECDISCARD is submitted will also potentially > be affected by the hung task timeouts. > > So prevent hung_check from firing by taking same approach used > in blk_execute_rq(), and the wake-up interval is set as half the > hung_check timer period, which keeps overhead low enough. > > Cc: Salman Qazi <sqazi@xxxxxxxxxx> > Cc: Jesse Barnes <jsbarnes@xxxxxxxxxx> > Cc: Bart Van Assche <bvanassche@xxxxxxx> > Link: https://lkml.org/lkml/2020/2/12/1193 > Reported-by: Salman Qazi <sqazi@xxxxxxxxxx> > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> > --- > block/bio.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/block/bio.c b/block/bio.c > index 94d697217887..c9ce19a86de7 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -17,6 +17,7 @@ > #include <linux/cgroup.h> > #include <linux/blk-cgroup.h> > #include <linux/highmem.h> > +#include <linux/sched/sysctl.h> > > #include <trace/events/block.h> > #include "blk.h" > @@ -1019,12 +1020,19 @@ static void submit_bio_wait_endio(struct bio *bio) > int submit_bio_wait(struct bio *bio) > { > DECLARE_COMPLETION_ONSTACK_MAP(done, bio->bi_disk->lockdep_map); > + unsigned long hang_check; > > bio->bi_private = &done; > bio->bi_end_io = submit_bio_wait_endio; > bio->bi_opf |= REQ_SYNC; > submit_bio(bio); > - wait_for_completion_io(&done); > + > + /* Prevent hang_check timer from firing at us during very long I/O */ > + hang_check = sysctl_hung_task_timeout_secs; > + if (hang_check) > + while (!wait_for_completion_io_timeout(&done, hang_check * (HZ/2))); > + else > + wait_for_completion_io(&done); > > return blk_status_to_errno(bio->bi_status); > } > -- > 2.20.1 >
