--- /dev/null
+From foo@baz Wed Mar 10 01:11:30 PM CET 2021
+From: Jeffle Xu <jefflexu@linux.alibaba.com>
+Date: Tue, 9 Mar 2021 11:04:31 +0800
+Subject: dm table: fix iterate_devices based device capability checks
+To: snitzer@redhat.com, gregkh@linuxfoundation.org, sashal@kernel.org
+Cc: stable@vger.kernel.org, jefflexu@linux.alibaba.com
+Message-ID: <20210309030431.85939-1-jefflexu@linux.alibaba.com>
+
+From: Jeffle Xu <jefflexu@linux.alibaba.com>
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/md/dm-table.c | 83 +++++++++++++++++++++++++++++++-------------------
+ 1 file changed, 53 insertions(+), 30 deletions(-)
+
+--- a/drivers/md/dm-table.c
++++ b/drivers/md/dm-table.c
+@@ -1210,6 +1210,46 @@ struct dm_target *dm_table_find_target(s
+ 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
+ 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,
+@@ -1396,29 +1436,12 @@ static int device_is_not_random(struct d
+ 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,
+@@ -1511,18 +1534,18 @@ void dm_table_set_restrictions(struct dm
+ 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
+ * 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);
+
+ /*
projects / thirdparty / kernel / stable-queue.git / commitdiff
