__blkdev_issue_discard() always returns 0, making the error check
in blkdev_issue_discard() dead code.

In function blkdev_issue_discard() initialize ret = 0, remove ret
assignment from __blkdev_issue_discard(), rely on bio == NULL check to
call submit_bio_wait(), preserve submit_bio_wait() error handling, and
preserve -EOPNOTSUPP to 0 mapping.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
---
 block/blk-lib.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 3030a772d3aa..19e0203cc18a 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -87,11 +87,11 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 {
 	struct bio *bio = NULL;
 	struct blk_plug plug;
-	int ret;
+	int ret = 0;
 
 	blk_start_plug(&plug);
-	ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, &bio);
-	if (!ret && bio) {
+	__blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, &bio);
+	if (bio) {
 		ret = submit_bio_wait(bio);
 		if (ret == -EOPNOTSUPP)
 			ret = 0;
-- 
2.40.0

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?

-- 
Jens Axboe

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@gmail.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@gmail.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

On 11/25/25 12:09 PM, Chaitanya Kulkarni wrote:
> 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.

OK, that make sense. I'll queue patch 1.

-- 
Jens Axboe