diff options
author | Chengming Zhou <zhouchengming@bytedance.com> | 2023-11-20 04:25:21 +0100 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2023-11-20 18:26:26 +0100 |
commit | 53f2bca2609237f910531f2c1a7779b16ce7952d (patch) | |
tree | 6a9108d20cdb839ecbc8fa184ebc3b788cd59eb9 /drivers/block | |
parent | block: Remove blk_set_runtime_active() (diff) | |
download | linux-53f2bca2609237f910531f2c1a7779b16ce7952d.tar.xz linux-53f2bca2609237f910531f2c1a7779b16ce7952d.zip |
block/null_blk: Fix double blk_mq_start_request() warning
When CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION is enabled, null_queue_rq()
would return BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE for the request,
which has been marked as MQ_RQ_IN_FLIGHT by blk_mq_start_request().
Then null_queue_rqs() put these requests in the rqlist, return back to
the block layer core, which would try to queue them individually again,
so the warning in blk_mq_start_request() triggered.
Fix it by splitting the null_queue_rq() into two parts: the first is the
preparation of request, the second is the handling of request. We put
the blk_mq_start_request() after the preparation part, which may fail
and return back to the block layer core.
The throttling also belongs to the preparation part, so move it before
blk_mq_start_request(). And change the return type of null_handle_cmd()
to void, since it always return BLK_STS_OK now.
Reported-by: <syzbot+fcc47ba2476570cbbeb0@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/all/0000000000000e6aac06098aee0c@google.com/
Fixes: d78bfa1346ab ("block/null_blk: add queue_rqs() support")
Suggested-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Link: https://lore.kernel.org/r/20231120032521.1012037-1-chengming.zhou@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block')
-rw-r--r-- | drivers/block/null_blk/main.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c index 22a3cf7f32e2..3021d58ca51c 100644 --- a/drivers/block/null_blk/main.c +++ b/drivers/block/null_blk/main.c @@ -1464,19 +1464,13 @@ blk_status_t null_process_cmd(struct nullb_cmd *cmd, enum req_op op, return BLK_STS_OK; } -static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector, - sector_t nr_sectors, enum req_op op) +static void null_handle_cmd(struct nullb_cmd *cmd, sector_t sector, + sector_t nr_sectors, enum req_op op) { struct nullb_device *dev = cmd->nq->dev; struct nullb *nullb = dev->nullb; blk_status_t sts; - if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) { - sts = null_handle_throttled(cmd); - if (sts != BLK_STS_OK) - return sts; - } - if (op == REQ_OP_FLUSH) { cmd->error = errno_to_blk_status(null_handle_flush(nullb)); goto out; @@ -1493,7 +1487,6 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd, sector_t sector, out: nullb_complete_cmd(cmd); - return BLK_STS_OK; } static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer) @@ -1724,8 +1717,6 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx, cmd->fake_timeout = should_timeout_request(rq) || blk_should_fake_timeout(rq->q); - blk_mq_start_request(rq); - if (should_requeue_request(rq)) { /* * Alternate between hitting the core BUSY path, and the @@ -1738,6 +1729,15 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx, return BLK_STS_OK; } + if (test_bit(NULLB_DEV_FL_THROTTLED, &nq->dev->flags)) { + blk_status_t sts = null_handle_throttled(cmd); + + if (sts != BLK_STS_OK) + return sts; + } + + blk_mq_start_request(rq); + if (is_poll) { spin_lock(&nq->poll_lock); list_add_tail(&rq->queuelist, &nq->poll_list); @@ -1747,7 +1747,8 @@ static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx, if (cmd->fake_timeout) return BLK_STS_OK; - return null_handle_cmd(cmd, sector, nr_sectors, req_op(rq)); + null_handle_cmd(cmd, sector, nr_sectors, req_op(rq)); + return BLK_STS_OK; } static void null_queue_rqs(struct request **rqlist) |