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
