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Commit f6453ec5 authored by Jeffle Xu's avatar Jeffle Xu Committed by Greg Kroah-Hartman
Browse files

dm table: fix iterate_devices based device capability checks 



commit a4c8dd9c2d0987cf542a2a0c42684c9c6d78a04e upstream.

According to the definition of dm_iterate_devices_fn:
 * This function must iterate through each section of device used by the
 * target until it encounters a non-zero return code, which it then returns.
 * Returns zero if no callout returned non-zero.

For some target type (e.g. dm-stripe), one call of iterate_devices() may
iterate multiple underlying devices internally, in which case a non-zero
return code returned by iterate_devices_callout_fn will stop the iteration
in advance. No iterate_devices_callout_fn should return non-zero unless
device iteration should stop.

Rename dm_table_requires_stable_pages() to dm_table_any_dev_attr() and
elevate it for reuse to stop iterating (and return non-zero) on the
first device that causes iterate_devices_callout_fn to return non-zero.
Use dm_table_any_dev_attr() to properly iterate through devices.

Rename device_is_nonrot() to device_is_rotational() and invert logic
accordingly to fix improper disposition.

[jeffle: backport notes]
No stable writes. Also convert the no_sg_merge capability check,
which is introduced by commit 200612ec ("dm table: propagate
QUEUE_FLAG_NO_SG_MERGE"), and removed since commit 2705c93742e9 ("block:
kill QUEUE_FLAG_NO_SG_MERGE") in v5.1.

Fixes: c3c4555e ("dm table: clear add_random unless all devices have it set")
Fixes: 4693c966 ("dm table: propagate non rotational flag")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 12a9ffac

drivers/md/dm-table.c

+53 −30
Original line number Diff line number Diff line
@@ -1210,6 +1210,46 @@ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector) 
	return &t->targets[(KEYS_PER_NODE * n) + k];

}



/*

 * type->iterate_devices() should be called when the sanity check needs to

 * iterate and check all underlying data devices. iterate_devices() will

 * iterate all underlying data devices until it encounters a non-zero return

 * code, returned by whether the input iterate_devices_callout_fn, or

 * iterate_devices() itself internally.

 *

 * For some target type (e.g. dm-stripe), one call of iterate_devices() may

 * iterate multiple underlying devices internally, in which case a non-zero

 * return code returned by iterate_devices_callout_fn will stop the iteration

 * in advance.

 *

 * Cases requiring _any_ underlying device supporting some kind of attribute,

 * should use the iteration structure like dm_table_any_dev_attr(), or call

 * it directly. @func should handle semantics of positive examples, e.g.

 * capable of something.

 *

 * Cases requiring _all_ underlying devices supporting some kind of attribute,

 * should use the iteration structure like dm_table_supports_nowait() or

 * dm_table_supports_discards(). Or introduce dm_table_all_devs_attr() that

 * uses an @anti_func that handle semantics of counter examples, e.g. not

 * capable of something. So: return !dm_table_any_dev_attr(t, anti_func);

 */

static bool dm_table_any_dev_attr(struct dm_table *t,

				  iterate_devices_callout_fn func)

{

	struct dm_target *ti;

	unsigned int i;



	for (i = 0; i < dm_table_get_num_targets(t); i++) {

		ti = dm_table_get_target(t, i);



		if (ti->type->iterate_devices &&

		    ti->type->iterate_devices(ti, func, NULL))

			return true;

        }



	return false;

}



static int count_device(struct dm_target *ti, struct dm_dev *dev,

			sector_t start, sector_t len, void *data)

{
@@ -1380,12 +1420,12 @@ static bool dm_table_discard_zeroes_data(struct dm_table *t) 
	return true;

}



static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,

static int device_is_rotational(struct dm_target *ti, struct dm_dev *dev,

				sector_t start, sector_t len, void *data)

{

	struct request_queue *q = bdev_get_queue(dev->bdev);



	return q && blk_queue_nonrot(q);

	return q && !blk_queue_nonrot(q);

}



static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
@@ -1396,29 +1436,12 @@ static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev, 
	return q && !blk_queue_add_random(q);

}



static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,

static int queue_no_sg_merge(struct dm_target *ti, struct dm_dev *dev,

			     sector_t start, sector_t len, void *data)

{

	struct request_queue *q = bdev_get_queue(dev->bdev);



	return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);

}



static bool dm_table_all_devices_attribute(struct dm_table *t,

					   iterate_devices_callout_fn func)

{

	struct dm_target *ti;

	unsigned i = 0;



	while (i < dm_table_get_num_targets(t)) {

		ti = dm_table_get_target(t, i++);



		if (!ti->type->iterate_devices ||

		    !ti->type->iterate_devices(ti, func, NULL))

			return false;

	}



	return true;

	return q && test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);

}



static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
@@ -1511,18 +1534,18 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, 
		q->limits.discard_zeroes_data = 0;



	/* Ensure that all underlying devices are non-rotational. */

	if (dm_table_all_devices_attribute(t, device_is_nonrot))

		queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);

	else

	if (dm_table_any_dev_attr(t, device_is_rotational))

		queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);

	else

		queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);



	if (!dm_table_supports_write_same(t))

		q->limits.max_write_same_sectors = 0;



	if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))

		queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);

	else

	if (dm_table_any_dev_attr(t, queue_no_sg_merge))

		queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);

	else

		queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);



	dm_table_verify_integrity(t);
@@ -1532,7 +1555,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, 
	 * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not

	 * have it set.

	 */

	if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))

	if (blk_queue_add_random(q) && dm_table_any_dev_attr(t, device_is_not_random))

		queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);



	/*