diff options
author | Ming Lei <ming.lei@redhat.com> | 2020-06-24 16:00:58 -0400 |
---|---|---|
committer | Mike Snitzer <snitzer@redhat.com> | 2020-07-07 12:00:01 -0400 |
commit | 85067747cf9888249fa11fa49ef75af5192d3988 (patch) | |
tree | 4ae28ab98db5eec5c1eae0e14f15a99df4e0604d /drivers/md/dm.c | |
parent | dcb7fd82c75ee2d6e6f9d8cc71c52519ed52e258 (diff) | |
download | linux-85067747cf9888249fa11fa49ef75af5192d3988.tar.bz2 |
dm: do not use waitqueue for request-based DM
Given request-based DM now uses blk-mq's blk_mq_queue_inflight() to
determine if outstanding IO has completed (and DM has no control over
the blk-mq state machine used to track outstanding IO) it is unsafe to
wakeup waiter (dm_wait_for_completion) before blk-mq has cleared a
request's state bits (e.g. MQ_RQ_IN_FLIGHT or MQ_RQ_COMPLETE). As
such dm_wait_for_completion() could be left to wait indefinitely if no
other requests complete.
Fix this by eliminating request-based DM's use of waitqueue to wait
for blk-mq requests to complete in dm_wait_for_completion.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Depends-on: 3c94d83cb3526 ("blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()")
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r-- | drivers/md/dm.c | 64 |
1 files changed, 39 insertions, 25 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index e6807792fec8..446aff589732 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -654,28 +654,6 @@ static void free_tio(struct dm_target_io *tio) bio_put(&tio->clone); } -static bool md_in_flight_bios(struct mapped_device *md) -{ - int cpu; - struct hd_struct *part = &dm_disk(md)->part0; - long sum = 0; - - for_each_possible_cpu(cpu) { - sum += part_stat_local_read_cpu(part, in_flight[0], cpu); - sum += part_stat_local_read_cpu(part, in_flight[1], cpu); - } - - return sum != 0; -} - -static bool md_in_flight(struct mapped_device *md) -{ - if (queue_is_mq(md->queue)) - return blk_mq_queue_inflight(md->queue); - else - return md_in_flight_bios(md); -} - u64 dm_start_time_ns_from_clone(struct bio *bio) { struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone); @@ -2470,15 +2448,29 @@ void dm_put(struct mapped_device *md) } EXPORT_SYMBOL_GPL(dm_put); -static int dm_wait_for_completion(struct mapped_device *md, long task_state) +static bool md_in_flight_bios(struct mapped_device *md) +{ + int cpu; + struct hd_struct *part = &dm_disk(md)->part0; + long sum = 0; + + for_each_possible_cpu(cpu) { + sum += part_stat_local_read_cpu(part, in_flight[0], cpu); + sum += part_stat_local_read_cpu(part, in_flight[1], cpu); + } + + return sum != 0; +} + +static int dm_wait_for_bios_completion(struct mapped_device *md, long task_state) { int r = 0; DEFINE_WAIT(wait); - while (1) { + while (true) { prepare_to_wait(&md->wait, &wait, task_state); - if (!md_in_flight(md)) + if (!md_in_flight_bios(md)) break; if (signal_pending_state(task_state, current)) { @@ -2493,6 +2485,28 @@ static int dm_wait_for_completion(struct mapped_device *md, long task_state) return r; } +static int dm_wait_for_completion(struct mapped_device *md, long task_state) +{ + int r = 0; + + if (!queue_is_mq(md->queue)) + return dm_wait_for_bios_completion(md, task_state); + + while (true) { + if (!blk_mq_queue_inflight(md->queue)) + break; + + if (signal_pending_state(task_state, current)) { + r = -EINTR; + break; + } + + msleep(5); + } + + return r; +} + /* * Process the deferred bios */ |