On Fri, Mar 05, 2021 at 02:55:22PM +0800, Jeffle Xu wrote:
> 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.
>
> Fixes: c3c4555edd10 ("dm table: clear add_random unless all devices have it set")
> Fixes: 4693c9668fdc ("dm table: propagate non rotational flag")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
> ---
> drivers/md/dm-table.c | 97 +++++++++++++++++++++++--------------------
> 1 file changed, 51 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index 916433742485..686cc7c20113 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -1392,6 +1392,46 @@ 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)
> {
> @@ -1708,12 +1748,12 @@ static int dm_table_supports_dax_write_cache(struct dm_table *t)
> return false;
> }
>
> -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,
> @@ -1732,23 +1772,6 @@ static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
> 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;
> -
> - 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 false;
> - }
> -
> - return true;
> -}
> -
> static int device_no_partial_completion(struct dm_target *ti, struct dm_dev *dev,
> sector_t start, sector_t len, void *data)
> {
> @@ -1887,27 +1910,6 @@ static int device_requires_stable_pages(struct dm_target *ti,
> return q && bdi_cap_stable_pages_required(q->backing_dev_info);
> }
>
> -/*
> - * If any underlying device requires stable pages, a table must require
> - * them as well. Only targets that support iterate_devices are considered:
> - * don't want error, zero, etc to require stable pages.
> - */
> -static bool dm_table_requires_stable_pages(struct dm_table *t)
> -{
> - struct dm_target *ti;
> - unsigned 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, device_requires_stable_pages, NULL))
> - return true;
> - }
> -
> - return false;
> -}
> -
> void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
> struct queue_limits *limits)
> {
> @@ -1948,10 +1950,10 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
> dax_write_cache(t->md->dax_dev, true);
>
> /* Ensure that all underlying devices are non-rotational. */
> - if (dm_table_all_devices_attribute(t, device_is_nonrot))
> - blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
> - else
> + if (dm_table_any_dev_attr(t, device_is_rotational))
> blk_queue_flag_clear(QUEUE_FLAG_NONROT, q);
> + else
> + blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
>
> if (!dm_table_supports_write_same(t))
> q->limits.max_write_same_sectors = 0;
> @@ -1968,8 +1970,11 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
> /*
> * Some devices don't use blk_integrity but still want stable pages
> * because they do their own checksumming.
> + * If any underlying device requires stable pages, a table must require
> + * them as well. Only targets that support iterate_devices are considered:
> + * don't want error, zero, etc to require stable pages.
> */
> - if (dm_table_requires_stable_pages(t))
> + if (dm_table_any_dev_attr(t, device_requires_stable_pages))
> q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
> else
> q->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES;
> @@ -1980,7 +1985,7 @@ 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))
> blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q);
> }
>
> --
> 2.27.0
>
Breaks the build :(
