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 200612ec33e5 ("dm table: propagate QUEUE_FLAG_NO_SG_MERGE"), and removed since commit 2705c93742e9 ("block: kill QUEUE_FLAG_NO_SG_MERGE") in v5.1.

Fixes: c3c4555edd10 ("dm table: clear add_random unless all devices have it set") Fixes: 4693c9668fdc ("dm table: propagate non rotational flag") Cc: stable@vger.kernel.org Signed-off-by: Jeffle Xu jefflexu@linux.alibaba.com Signed-off-by: Mike Snitzer snitzer@redhat.com --- drivers/md/dm-table.c | 83 +++++++++++++++++++++++++++---------------- 1 file changed, 53 insertions(+), 30 deletions(-)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 5d120c3cee57..1728e3638136 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1306,6 +1306,46 @@ 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) { @@ -1476,12 +1516,12 @@ 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, - sector_t start, sector_t len, void *data) +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, @@ -1492,29 +1532,12 @@ 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, - sector_t start, sector_t len, void *data) +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, @@ -1607,18 +1630,18 @@ 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);

@@ -1628,7 +1651,7 @@ 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);

/*