[PATCH 0/2] target: remove dead kmap checks

[PATCH 0/2] target: remove dead kmap checks

[shao.mingyin]

kmap() and kmap_local_page() never return NULL, so the checks after them are
dead code.  Remove them.

No functional change intended; both patches are independent and can be
applied on their own or as a subset.

Signed-off-by: Shao Mingyin <shao.mingyin@zte.com.cn>
---
base-commit: 7649ba73f9e7e1e04d0b46213e39c79ae09dd55c

[PATCH 1/2] target: iblock: drop the dead kmap() NULL check

[shao.mingyin]

From: Shao Mingyin <shao.mingyin@zte.com.cn>

kmap() never returns NULL, so the check after it is dead code.

No functional change.

Signed-off-by: Shao Mingyin <shao.mingyin@zte.com.cn>
---
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index ea65d39fef88..604fca959f2e 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -461,8 +461,6 @@ iblock_execute_zero_out(struct block_device *bdev, struct se_cmd *cmd)
 	int ret;
 
 	buf = kmap(sg_page(sg)) + sg->offset;
-	if (!buf)
-		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 	/*
 	 * Fall back to block_execute_write_same() slow-path if
 	 * incoming WRITE_SAME payload does not contain zeros.

Re: [PATCH 1/2] target: iblock: drop the dead kmap() NULL check

[Laurence Oberman]

On Thu, 2026-11-05 at 19:33 +0800, shao.mingyin@zte.com.cn wrote:
> From: Shao Mingyin <shao.mingyin@zte.com.cn>
> 
> kmap() never returns NULL, so the check after it is dead code.
> 
> No functional change.
> 
> Signed-off-by: Shao Mingyin <shao.mingyin@zte.com.cn>
> ---
> diff --git a/drivers/target/target_core_iblock.c
> b/drivers/target/target_core_iblock.c
> index ea65d39fef88..604fca959f2e 100644
> --- a/drivers/target/target_core_iblock.c
> +++ b/drivers/target/target_core_iblock.c
> @@ -461,8 +461,6 @@ iblock_execute_zero_out(struct block_device
> *bdev, struct se_cmd *cmd)
>  	int ret;
>  
>  	buf = kmap(sg_page(sg)) + sg->offset;
> -	if (!buf)
> -		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
>  	/*
>  	 * Fall back to block_execute_write_same() slow-path if
>  	 * incoming WRITE_SAME payload does not contain zeros.

Looks good.
Reviewed-by: Laurence Oberman <loberman@redhat.com>

[PATCH 2/2] target: core: drop the dead kmap_local_page() NULL check

[shao.mingyin]

From: Shao Mingyin <shao.mingyin@zte.com.cn>

kmap_local_page() never returns NULL; drop the wrapper and always
zero the segment.

No functional change.

Signed-off-by: Shao Mingyin <shao.mingyin@zte.com.cn>
---
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 927861c30afc..9819515ce967 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1646,10 +1646,8 @@ static int __target_submit(struct se_cmd *cmd)
 			BUG_ON(!sgl);
 
 			buf = kmap_local_page(sg_page(sgl));
-			if (buf) {
-				memset(buf + sgl->offset, 0, sgl->length);
-				kunmap_local(buf);
-			}
+			memset(buf + sgl->offset, 0, sgl->length);
+			kunmap_local(buf);
 		}
 	}

Re: [PATCH 0/2] target: remove dead kmap checks

[Martin K. Petersen]

> kmap() and kmap_local_page() never return NULL, so the checks after
> them are dead code. Remove them.
>
> No functional change intended; both patches are independent and can be
> applied on their own or as a subset.

Applied to 7.5/scsi-staging, thanks!

-- 
Martin K. Petersen