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Commit f5fe1b51 authored by NeilBrown's avatar NeilBrown Committed by Jens Axboe
Browse files

blk: Ensure users for current->bio_list can see the full list. 



Commit 79bd9959 ("blk: improve order of bio handling in generic_make_request()")
changed current->bio_list so that it did not contain *all* of the
queued bios, but only those submitted by the currently running
make_request_fn.

There are two places which walk the list and requeue selected bios,
and others that check if the list is empty.  These are no longer
correct.

So redefine current->bio_list to point to an array of two lists, which
contain all queued bios, and adjust various code to test or walk both
lists.

Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Fixes: 79bd9959 ("blk: improve order of bio handling in generic_make_request()")
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 84c37c16

block/bio.c

+9 −3
Original line number Diff line number Diff line
@@ -376,10 +376,14 @@ static void punt_bios_to_rescuer(struct bio_set *bs) 
	bio_list_init(&punt);

	bio_list_init(&nopunt);



	while ((bio = bio_list_pop(current->bio_list)))

	while ((bio = bio_list_pop(&current->bio_list[0])))

		bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);

	current->bio_list[0] = nopunt;



	*current->bio_list = nopunt;

	bio_list_init(&nopunt);

	while ((bio = bio_list_pop(&current->bio_list[1])))

		bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);

	current->bio_list[1] = nopunt;



	spin_lock(&bs->rescue_lock);

	bio_list_merge(&bs->rescue_list, &punt);
@@ -466,7 +470,9 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) 
		 * we retry with the original gfp_flags.

		 */



		if (current->bio_list && !bio_list_empty(current->bio_list))

		if (current->bio_list &&

		    (!bio_list_empty(&current->bio_list[0]) ||

		     !bio_list_empty(&current->bio_list[1])))

			gfp_mask &= ~__GFP_DIRECT_RECLAIM;



		p = mempool_alloc(bs->bio_pool, gfp_mask);

block/blk-core.c

+18 −12
Original line number Diff line number Diff line
@@ -1973,7 +1973,14 @@ generic_make_request_checks(struct bio *bio) 
 */

blk_qc_t generic_make_request(struct bio *bio)

{

	struct bio_list bio_list_on_stack;

	/*

	 * bio_list_on_stack[0] contains bios submitted by the current

	 * make_request_fn.

	 * bio_list_on_stack[1] contains bios that were submitted before

	 * the current make_request_fn, but that haven't been processed

	 * yet.

	 */

	struct bio_list bio_list_on_stack[2];

	blk_qc_t ret = BLK_QC_T_NONE;



	if (!generic_make_request_checks(bio))
@@ -1990,7 +1997,7 @@ blk_qc_t generic_make_request(struct bio *bio) 
	 * should be added at the tail

	 */

	if (current->bio_list) {

		bio_list_add(current->bio_list, bio);

		bio_list_add(&current->bio_list[0], bio);

		goto out;

	}
@@ -2009,18 +2016,17 @@ blk_qc_t generic_make_request(struct bio *bio) 
	 * bio_list, and call into ->make_request() again.

	 */

	BUG_ON(bio->bi_next);

	bio_list_init(&bio_list_on_stack);

	current->bio_list = &bio_list_on_stack;

	bio_list_init(&bio_list_on_stack[0]);

	current->bio_list = bio_list_on_stack;

	do {

		struct request_queue *q = bdev_get_queue(bio->bi_bdev);



		if (likely(blk_queue_enter(q, false) == 0)) {

			struct bio_list hold;

			struct bio_list lower, same;



			/* Create a fresh bio_list for all subordinate requests */

			hold = bio_list_on_stack;

			bio_list_init(&bio_list_on_stack);

			bio_list_on_stack[1] = bio_list_on_stack[0];

			bio_list_init(&bio_list_on_stack[0]);

			ret = q->make_request_fn(q, bio);



			blk_queue_exit(q);
@@ -2030,19 +2036,19 @@ blk_qc_t generic_make_request(struct bio *bio) 
			 */

			bio_list_init(&lower);

			bio_list_init(&same);

			while ((bio = bio_list_pop(&bio_list_on_stack)) != NULL)

			while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL)

				if (q == bdev_get_queue(bio->bi_bdev))

					bio_list_add(&same, bio);

				else

					bio_list_add(&lower, bio);

			/* now assemble so we handle the lowest level first */

			bio_list_merge(&bio_list_on_stack, &lower);

			bio_list_merge(&bio_list_on_stack, &same);

			bio_list_merge(&bio_list_on_stack, &hold);

			bio_list_merge(&bio_list_on_stack[0], &lower);

			bio_list_merge(&bio_list_on_stack[0], &same);

			bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]);

		} else {

			bio_io_error(bio);

		}

		bio = bio_list_pop(current->bio_list);

		bio = bio_list_pop(&bio_list_on_stack[0]);

	} while (bio);

	current->bio_list = NULL; /* deactivate */

drivers/md/dm.c

+16 −13
Original line number Diff line number Diff line
@@ -989,19 +989,21 @@ static void flush_current_bio_list(struct blk_plug_cb *cb, bool from_schedule) 
	struct dm_offload *o = container_of(cb, struct dm_offload, cb);

	struct bio_list list;

	struct bio *bio;

	int i;



	INIT_LIST_HEAD(&o->cb.list);



	if (unlikely(!current->bio_list))

		return;



	list = *current->bio_list;

	bio_list_init(current->bio_list);

	for (i = 0; i < 2; i++) {

		list = current->bio_list[i];

		bio_list_init(&current->bio_list[i]);



		while ((bio = bio_list_pop(&list))) {

			struct bio_set *bs = bio->bi_pool;

			if (unlikely(!bs) || bs == fs_bio_set) {

			bio_list_add(current->bio_list, bio);

				bio_list_add(&current->bio_list[i], bio);

				continue;

			}
@@ -1011,6 +1013,7 @@ static void flush_current_bio_list(struct blk_plug_cb *cb, bool from_schedule) 
			spin_unlock(&bs->rescue_lock);

		}

	}

}



static void dm_offload_start(struct dm_offload *o)

{

drivers/md/raid10.c

+2 −1
Original line number Diff line number Diff line
@@ -974,7 +974,8 @@ static void wait_barrier(struct r10conf *conf) 
				    !conf->barrier ||

				    (atomic_read(&conf->nr_pending) &&

				     current->bio_list &&

				     !bio_list_empty(current->bio_list)),

				     (!bio_list_empty(&current->bio_list[0]) ||

				      !bio_list_empty(&current->bio_list[1]))),

				    conf->resync_lock);

		conf->nr_waiting--;

		if (!conf->nr_waiting)