__blkdev_issue_discard() always returns 0, making the error checking
in nvmet_bdev_discard_range() dead code.

Kill the function nvmet_bdev_discard_range() and call
__blkdev_issue_discard() directly from nvmet_bdev_execute_discard(),
since no error handling is needed anymore for __blkdev_issue_discard()
call.

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
---
 drivers/nvme/target/io-cmd-bdev.c | 28 +++++++---------------------
 1 file changed, 7 insertions(+), 21 deletions(-)

diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index 8d246b8ca604..ca7731048940 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -362,29 +362,14 @@ u16 nvmet_bdev_flush(struct nvmet_req *req)
 	return 0;
 }
 
-static u16 nvmet_bdev_discard_range(struct nvmet_req *req,
-		struct nvme_dsm_range *range, struct bio **bio)
-{
-	struct nvmet_ns *ns = req->ns;
-	int ret;
-
-	ret = __blkdev_issue_discard(ns->bdev,
-			nvmet_lba_to_sect(ns, range->slba),
-			le32_to_cpu(range->nlb) << (ns->blksize_shift - 9),
-			GFP_KERNEL, bio);
-	if (ret && ret != -EOPNOTSUPP) {
-		req->error_slba = le64_to_cpu(range->slba);
-		return errno_to_nvme_status(req, ret);
-	}
-	return NVME_SC_SUCCESS;
-}
-
 static void nvmet_bdev_execute_discard(struct nvmet_req *req)
 {
+	struct nvmet_ns *ns = req->ns;
 	struct nvme_dsm_range range;
 	struct bio *bio = NULL;
+	sector_t nr_sects;
 	int i;
-	u16 status;
+	u16 status = NVME_SC_SUCCESS;
 
 	for (i = 0; i <= le32_to_cpu(req->cmd->dsm.nr); i++) {
 		status = nvmet_copy_from_sgl(req, i * sizeof(range), &range,
@@ -392,9 +377,10 @@ static void nvmet_bdev_execute_discard(struct nvmet_req *req)
 		if (status)
 			break;
 
-		status = nvmet_bdev_discard_range(req, &range, &bio);
-		if (status)
-			break;
+		nr_sects = le32_to_cpu(range.nlb) << (ns->blksize_shift - 9);
+		__blkdev_issue_discard(ns->bdev,
+				nvmet_lba_to_sect(ns, range.slba), nr_sects,
+				GFP_KERNEL, &bio);
 	}
 
 	if (bio) {
-- 
2.40.0

On 11/25/25 07:48, Chaitanya Kulkarni wrote:
> __blkdev_issue_discard() always returns 0, making the error checking
> in nvmet_bdev_discard_range() dead code.
> 
> Kill the function nvmet_bdev_discard_range() and call
> __blkdev_issue_discard() directly from nvmet_bdev_execute_discard(),
> since no error handling is needed anymore for __blkdev_issue_discard()
> call.
> 
> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
> ---
>   drivers/nvme/target/io-cmd-bdev.c | 28 +++++++---------------------
>   1 file changed, 7 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
> index 8d246b8ca604..ca7731048940 100644
> --- a/drivers/nvme/target/io-cmd-bdev.c
> +++ b/drivers/nvme/target/io-cmd-bdev.c
> @@ -362,29 +362,14 @@ u16 nvmet_bdev_flush(struct nvmet_req *req)
>   	return 0;
>   }
>   
> -static u16 nvmet_bdev_discard_range(struct nvmet_req *req,
> -		struct nvme_dsm_range *range, struct bio **bio)
> -{
> -	struct nvmet_ns *ns = req->ns;
> -	int ret;
> -
> -	ret = __blkdev_issue_discard(ns->bdev,
> -			nvmet_lba_to_sect(ns, range->slba),
> -			le32_to_cpu(range->nlb) << (ns->blksize_shift - 9),
> -			GFP_KERNEL, bio);
> -	if (ret && ret != -EOPNOTSUPP) {
> -		req->error_slba = le64_to_cpu(range->slba);
> -		return errno_to_nvme_status(req, ret);
> -	}
> -	return NVME_SC_SUCCESS;
> -}
> -
>   static void nvmet_bdev_execute_discard(struct nvmet_req *req)
>   {
> +	struct nvmet_ns *ns = req->ns;
>   	struct nvme_dsm_range range;
>   	struct bio *bio = NULL;
> +	sector_t nr_sects;
>   	int i;
> -	u16 status;
> +	u16 status = NVME_SC_SUCCESS;
>   
>   	for (i = 0; i <= le32_to_cpu(req->cmd->dsm.nr); i++) {
>   		status = nvmet_copy_from_sgl(req, i * sizeof(range), &range,
> @@ -392,9 +377,10 @@ static void nvmet_bdev_execute_discard(struct nvmet_req *req)
>   		if (status)
>   			break;
>   
> -		status = nvmet_bdev_discard_range(req, &range, &bio);
> -		if (status)
> -			break;
> +		nr_sects = le32_to_cpu(range.nlb) << (ns->blksize_shift - 9);
> +		__blkdev_issue_discard(ns->bdev,
> +				nvmet_lba_to_sect(ns, range.slba), nr_sects,
> +				GFP_KERNEL, &bio);

We also need to check for memory allocation errors in
__blkdev_issue_discard(). However, this cannot be done by simply
checking if bio is NULL. Similar to the issue with xfs_discard_extents,
once __blkdev_issue_discard()->blk_alloc_discard_bio() succeeds once,
any subsequent memory allocation failures cannot be detected by checking
if bio is NULL.

Yongpeng,

>   	}
>   
>   	if (bio) {

On Wed, Nov 26, 2025 at 06:14:32PM +0800, Yongpeng Yang wrote:
> We also need to check for memory allocation errors in
> __blkdev_issue_discard().

No, we still don't.  What is so hard to grasp about mempool allocations
even after repeated explanations?