linux-kernel - [PATCH RFC v3 13/15] block: skip unnecessary checks for split bio

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250901033220.42982-14-yukuai1@huaweicloud.com>
Date: Mon,  1 Sep 2025 11:32:18 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: hch@...radead.org,
	colyli@...nel.org,
	hare@...e.de,
	dlemoal@...nel.org,
	tieren@...as.com,
	axboe@...nel.dk,
	tj@...nel.org,
	josef@...icpanda.com,
	song@...nel.org,
	kmo@...erainc.com,
	satyat@...gle.com,
	ebiggers@...gle.com,
	neil@...wn.name,
	akpm@...ux-foundation.org
Cc: linux-block@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	cgroups@...r.kernel.org,
	linux-raid@...r.kernel.org,
	yukuai3@...wei.com,
	yukuai1@...weicloud.com,
	yi.zhang@...wei.com,
	yangerkun@...wei.com,
	johnny.chenyi@...wei.com
Subject: [PATCH RFC v3 13/15] block: skip unnecessary checks for split bio

From: Yu Kuai <yukuai3@...wei.com>

Lots of checks are already done while submitting this bio the first
time, and there is no need to check them again when this bio is
resubmitted after split.

Hence factor out a helper submit_split_bio_noacct() for resubmitting
bio after splitting, only should_fail_bio() and blk_throtl_bio() are
kept.

Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 block/blk-core.c  | 16 ++++++++++++++++
 block/blk-merge.c |  2 +-
 block/blk.h       |  1 +
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 4201504158a1..ea194a1a5b2c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -765,6 +765,22 @@ static blk_status_t blk_validate_atomic_write_op_size(struct request_queue *q,
 	return BLK_STS_OK;
 }
 
+/* resubmit a bio after split, see bio_submit_split_bioset() */
+void submit_split_bio_noacct(struct bio *bio)
+{
+	might_sleep();
+
+	if (should_fail_bio(bio)) {
+		bio_io_error(bio);
+		return;
+	}
+
+	if (blk_throtl_bio(bio))
+		return;
+
+	submit_bio_noacct_nocheck(bio);
+}
+
 /**
  * submit_bio_noacct - re-submit a bio to the block device layer for I/O
  * @bio:  The bio describing the location in memory and on the device.
diff --git a/block/blk-merge.c b/block/blk-merge.c
index e1afb07040c0..4feeaab0d3db 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -131,7 +131,7 @@ struct bio *bio_submit_split_bioset(struct bio *bio, unsigned int split_sectors,
 	bio_chain(split, bio);
 	trace_block_split(split, bio->bi_iter.bi_sector);
 	WARN_ON_ONCE(bio_zone_write_plugging(bio));
-	submit_bio_noacct(bio);
+	submit_split_bio_noacct(bio);
 
 	return split;
 }
diff --git a/block/blk.h b/block/blk.h
index 0268deb22268..68bf637ab7ca 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -54,6 +54,7 @@ bool blk_queue_start_drain(struct request_queue *q);
 bool __blk_freeze_queue_start(struct request_queue *q,
 			      struct task_struct *owner);
 int __bio_queue_enter(struct request_queue *q, struct bio *bio);
+void submit_split_bio_noacct(struct bio *bio);
 void submit_bio_noacct_nocheck(struct bio *bio);
 void bio_await_chain(struct bio *bio);
 
-- 
2.39.2