[patch 058/163] mm/page_io.c: use blk_io_schedule() for avoiding task hung in sync io

Andrew Morton
2020-08-07T06:20:21Z

From: Xianting Tian <xianting_tian@126.com>
Subject: mm/page_io.c: use blk_io_schedule() for avoiding task hung in sync io

swap_readpage() does the sync io for one page, the io is not big,
normally, the io can be finished quickly, but it may take long time or
wait forever in case of io failure or discard.

This patch uses blk_io_schedule() instead of io_schedule() to avoid task
hung and crash (when set /proc/sys/kernel/hung_task_panic) when the above
exception occurs.

This is similar to the hung task avoidance in submit_bio_wait(),
blk_execute_rq() and __blkdev_direct_IO().

Link: http://lkml.kernel.org/r/1596461807-21087-1-git-send-email-xianting_tian@126.com
Signed-off-by: Xianting Tian <xianting_tian@126.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

mm/page_io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/page_io.c~mm-use-blk_io_schedule-for-avoiding-task-hung-in-sync-io
+++ a/mm/page_io.c
@@ -441,7 +441,7 @@ int swap_readpage(struct page *page, boo
break;

if (!blk_poll(disk->queue, qc, true))
- io_schedule();
+ blk_io_schedule();
}
__set_current_state(TASK_RUNNING);
bio_put(bio);
_