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| author | Mike Snitzer <snitzer@kernel.org> | 2022-05-31 12:16:49 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@kernel.org> | 2022-05-31 14:44:17 -0400 |
| commit | 9571f829f30a89b888ec4c3a72f5a04573f0e058 (patch) | |
| tree | e1c49996912028edc6a6b51d551493c8ec74db87 | |
| parent | ca522482e3eafd005b8d4e8b1331c911505a58d5 (diff) | |
| download | linux-9571f829f30a89b888ec4c3a72f5a04573f0e058.tar.gz | |
dm table: fix dm_table_supports_poll to return false if no data devices
It was reported that the "generic/250" test in xfstests (which uses
the dm-error target) demonstrates a regression where the kernel
crashes in bioset_exit().
Since commit cfc97abcbe0b ("dm: conditionally enable
BIOSET_PERCPU_CACHE for dm_io bioset") the bioset_init() for the dm_io
bioset will setup the bioset's per-cpu alloc cache if all devices have
QUEUE_FLAG_POLL set.
But there was an bug where a target that doesn't have any data devices
(and that doesn't even set the .iterate_devices dm target callback)
will incorrectly return true from dm_table_supports_poll().
Fix this by updating dm_table_supports_poll() to follow dm-table.c's
well-worn pattern for testing that _all_ targets in a DM table do in
fact have underlying devices that set QUEUE_FLAG_POLL.
NOTE: An additional block fix is still needed so that
bio_alloc_cache_destroy() clears the bioset's ->cache member.
Otherwise, a DM device's table reload that transitions the DM device's
bioset from using a per-cpu alloc cache to _not_ using one will result
in bioset_exit() crashing in bio_alloc_cache_destroy() because dm's
dm_io bioset ("io_bs") was left with a stale ->cache member.
Fixes: cfc97abcbe0b ("dm: conditionally enable BIOSET_PERCPU_CACHE for dm_io bioset")
Reported-by: Matthew Wilcox <willy@infradead.org>
Reported-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
| -rw-r--r-- | drivers/md/dm-table.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index a37c7b76364302..0e833a154b31df 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1005,7 +1005,7 @@ bool dm_table_request_based(struct dm_table *t) return __table_type_request_based(dm_table_get_type(t)); } -static int dm_table_supports_poll(struct dm_table *t); +static bool dm_table_supports_poll(struct dm_table *t); static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md) { @@ -1027,7 +1027,7 @@ static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device * per_io_data_size = max(per_io_data_size, ti->per_io_data_size); min_pool_size = max(min_pool_size, ti->num_flush_bios); } - poll_supported = !!dm_table_supports_poll(t); + poll_supported = dm_table_supports_poll(t); } t->mempools = dm_alloc_md_mempools(md, type, per_io_data_size, min_pool_size, @@ -1547,9 +1547,20 @@ static int count_device(struct dm_target *ti, struct dm_dev *dev, return 0; } -static int dm_table_supports_poll(struct dm_table *t) +static bool dm_table_supports_poll(struct dm_table *t) { - return !dm_table_any_dev_attr(t, device_not_poll_capable, NULL); + 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, device_not_poll_capable, NULL)) + return false; + } + + return true; } /* |