linux-kernel - Re: [PATCH V3 1/6] block: ignore discard return value

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: <851516d5-a5e8-47dd-82e0-3e34090e600d@gmail.com>
Date: Tue, 25 Nov 2025 11:09:35 -0800
From: Chaitanya Kulkarni <ckulkarnilinux@...il.com>
To: Jens Axboe <axboe@...nel.dk>, agk@...hat.com, snitzer@...nel.org,
 mpatocka@...hat.com, song@...nel.org, yukuai@...as.com, hch@....de,
 sagi@...mberg.me, kch@...dia.com, jaegeuk@...nel.org, chao@...nel.org,
 cem@...nel.org
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
 dm-devel@...ts.linux.dev, linux-raid@...r.kernel.org,
 linux-nvme@...ts.infradead.org, linux-f2fs-devel@...ts.sourceforge.net,
 linux-xfs@...r.kernel.org, bpf@...r.kernel.org,
 Johannes Thumshirn <johannes.thumshirn@....com>,
 "Martin K . Petersen" <martin.petersen@...cle.com>
Subject: Re: [PATCH V3 1/6] block: ignore discard return value

On 11/25/25 09:38, Jens Axboe wrote:
> On 11/24/25 4:48 PM, Chaitanya Kulkarni wrote:
>> __blkdev_issue_discard() always returns 0, making the error check
>> in blkdev_issue_discard() dead code.
> Shouldn't it be a void instead then?
>
Yes, we have decided to clean up the callers first [1]. Once they are
merged safely, after rc1 I'll send a patch [2] to make it void since
it touches many different subsystems.

-ck

[1]
https://marc.info/?l=linux-block&m=176405170918235&w=2
https://marc.info/?l=dm-devel&m=176345232320530&w=2

[2]
 From abdf4d1863a02d4be816aaab9a789f44bfca568f Mon Sep 17 00:00:00 2001
From: Chaitanya Kulkarni <ckulkarnilinux@...il.com>
Date: Tue, 18 Nov 2025 10:35:58 -0800
Subject: [PATCH 6/6] block: change discar return type to  void

Now that all callers have been updated to not check the return value
of __blkdev_issue_discard(), change its return type from int to void
and remove the return 0 statement.

This completes the cleanup of dead error checking code around
__blkdev_issue_discard().

Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@...il.com>
---
  block/blk-lib.c        | 3 +--
  include/linux/blkdev.h | 2 +-
  2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 19e0203cc18a..0a5f39325b2d 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -60,7 +60,7 @@ struct bio *blk_alloc_discard_bio(struct block_device *bdev,
  	return bio;
  }

-int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
+void __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop)
  {
  	struct bio *bio;
@@ -68,7 +68,6 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  	while ((bio = blk_alloc_discard_bio(bdev, &sector, &nr_sects,
  			gfp_mask)))
  		*biop = bio_chain_and_submit(*biop, bio);
-	return 0;
  }
  EXPORT_SYMBOL(__blkdev_issue_discard);

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f0ab02e0a673..b05c37d20b09 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1258,7 +1258,7 @@ extern void blk_io_schedule(void);

  int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  		sector_t nr_sects, gfp_t gfp_mask);
-int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
+void __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
  		sector_t nr_sects, gfp_t gfp_mask, struct bio **biop);
  int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
  		sector_t nr_sects, gfp_t gfp);
-- 
2.40.0