From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Ming Lei <ming.lei@redhat.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
NeilBrown <neilb@suse.com>, Jens Axboe <axboe@kernel.dk>,
Sasha Levin <sashal@kernel.org>,
linux-block@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 41/65] block: cover another queue enter recursion via BIO_QUEUE_ENTERED
Date: Thu, 14 Feb 2019 21:10:57 -0500 [thread overview]
Message-ID: <20190215021121.177674-41-sashal@kernel.org> (raw)
In-Reply-To: <20190215021121.177674-1-sashal@kernel.org>
From: Ming Lei <ming.lei@redhat.com>
[ Upstream commit 698cef173983b086977e633e46476e0f925ca01e ]
Except for blk_queue_split(), bio_split() is used for splitting bio too,
then the remained bio is often resubmit to queue via generic_make_request().
So the same queue enter recursion exits in this case too. Unfortunatley
commit cd4a4ae4683dc2 doesn't help this case.
This patch covers the above case by setting BIO_QUEUE_ENTERED before calling
q->make_request_fn.
In theory the per-bio flag is used to simulate one stack variable, it is
just fine to clear it after q->make_request_fn is returned. Especially
the same bio can't be submitted from another context.
Fixes: cd4a4ae4683dc2 ("block: don't use blocking queue entered for recursive bio submits")
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: NeilBrown <neilb@suse.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
block/blk-core.c | 11 +++++++++++
block/blk-merge.c | 10 ----------
2 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index eb8b52241453..a9fde80606d7 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2454,7 +2454,18 @@ blk_qc_t generic_make_request(struct bio *bio)
/* Create a fresh bio_list for all subordinate requests */
bio_list_on_stack[1] = bio_list_on_stack[0];
bio_list_init(&bio_list_on_stack[0]);
+
+ /*
+ * Since we're recursing into make_request here, ensure
+ * that we mark this bio as already having entered the queue.
+ * If not, and the queue is going away, we can get stuck
+ * forever on waiting for the queue reference to drop. But
+ * that will never happen, as we're already holding a
+ * reference to it.
+ */
+ bio_set_flag(bio, BIO_QUEUE_ENTERED);
ret = q->make_request_fn(q, bio);
+ bio_clear_flag(bio, BIO_QUEUE_ENTERED);
/* sort new bios into those for a lower level
* and those for the same level
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 2e042190a4f1..ba7f732c519e 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -211,16 +211,6 @@ void blk_queue_split(struct request_queue *q, struct bio **bio)
/* there isn't chance to merge the splitted bio */
split->bi_opf |= REQ_NOMERGE;
- /*
- * Since we're recursing into make_request here, ensure
- * that we mark this bio as already having entered the queue.
- * If not, and the queue is going away, we can get stuck
- * forever on waiting for the queue reference to drop. But
- * that will never happen, as we're already holding a
- * reference to it.
- */
- bio_set_flag(*bio, BIO_QUEUE_ENTERED);
-
bio_chain(split, *bio);
trace_block_split(q, split, (*bio)->bi_iter.bi_sector);
generic_make_request(*bio);
--
2.19.1
next parent reply other threads:[~2019-02-15 2:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190215021121.177674-1-sashal@kernel.org>
2019-02-15 2:10 ` Sasha Levin [this message]
2019-02-15 2:11 ` [PATCH AUTOSEL 4.19 65/65] Revert "block: cover another queue enter recursion via BIO_QUEUE_ENTERED" Sasha Levin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190215021121.177674-41-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=axboe@kernel.dk \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ming.lei@redhat.com \
--cc=neilb@suse.com \
--cc=penguin-kernel@I-love.SAKURA.ne.jp \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).