From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <tj@kernel.org>,
linux-block@vger.kernel.org, Ming Lei <ming.lei@redhat.com>
Subject: [PATCH 2/4] block: split bio_queue_enter from blk_queue_enter
Date: Mon, 20 Sep 2021 13:24:03 +0200 [thread overview]
Message-ID: <20210920112405.1299667-3-hch@lst.de> (raw)
In-Reply-To: <20210920112405.1299667-1-hch@lst.de>
To prepare for fixing a gendisk shutdown race, open code the
blk_queue_enter logic in bio_queue_enter. This also remove the
pointless flags translation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-core.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 4c078681f39b8..be7cd1819b605 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -475,18 +475,32 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags)
static inline int bio_queue_enter(struct bio *bio)
{
struct request_queue *q = bio->bi_bdev->bd_disk->queue;
- bool nowait = bio->bi_opf & REQ_NOWAIT;
- int ret;
- ret = blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0);
- if (unlikely(ret)) {
- if (nowait && !blk_queue_dying(q))
+ while (!blk_try_enter_queue(q, false)) {
+ if (bio->bi_opf & REQ_NOWAIT) {
bio_wouldblock_error(bio);
- else
+ return -EBUSY;
+ }
+
+ /*
+ * read pair of barrier in blk_freeze_queue_start(), we need to
+ * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and
+ * reading .mq_freeze_depth or queue dying flag, otherwise the
+ * following wait may never return if the two reads are
+ * reordered.
+ */
+ smp_rmb();
+ wait_event(q->mq_freeze_wq,
+ (!q->mq_freeze_depth &&
+ blk_pm_resume_queue(false, q)) ||
+ blk_queue_dying(q));
+ if (blk_queue_dying(q)) {
bio_io_error(bio);
+ return -ENODEV;
+ }
}
- return ret;
+ return 0;
}
void blk_queue_exit(struct request_queue *q)
--
2.30.2
next prev parent reply other threads:[~2021-09-20 11:26 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-20 11:24 tear down file system I/O in del_gendisk Christoph Hellwig
2021-09-20 11:24 ` [PATCH 1/4] block: factor out a blk_try_enter_queue helper Christoph Hellwig
2021-09-21 3:17 ` Bart Van Assche
2021-09-20 11:24 ` Christoph Hellwig [this message]
2021-09-21 3:25 ` [PATCH 2/4] block: split bio_queue_enter from blk_queue_enter Bart Van Assche
2021-09-20 11:24 ` [PATCH 3/4] block: drain file system I/O on del_gendisk Christoph Hellwig
2021-09-20 11:24 ` [PATCH 4/4] block: keep q_usage_counter in atomic mode after del_gendisk Christoph Hellwig
2021-09-21 3:29 ` Bart Van Assche
2021-09-21 9:07 ` Christoph Hellwig
2021-09-21 3:38 ` tear down file system I/O in del_gendisk Bart Van Assche
2021-09-21 9:08 ` Christoph Hellwig
2021-09-21 14:24 ` Bart Van Assche
2021-09-21 22:33 ` Bart Van Assche
2021-09-22 17:22 tear down file system I/O in del_gendisk v2 Christoph Hellwig
2021-09-22 17:22 ` [PATCH 2/4] block: split bio_queue_enter from blk_queue_enter Christoph Hellwig
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