s390/mm: Use pointer from memcpy() call for assignment in s390_replace_asce()

[PATCH] s390/mm: Use pointer from memcpy() call for assignment in s390_replace_asce()

Posted by Markus Elfring 3 months, 1 week ago

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Fri, 31 Oct 2025 07:56:06 +0100

A pointer was assigned to a variable. The same pointer was used for
the destination parameter of a memcpy() call.
This function is documented in the way that the same value is returned.
Thus convert two separate statements into a direct variable assignment for
the return value from a memory copy action.

The source code was transformed by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 arch/s390/mm/gmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 22c448b32340..e49e839933f1 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2440,8 +2440,8 @@ int s390_replace_asce(struct gmap *gmap)
 	page = gmap_alloc_crst();
 	if (!page)
 		return -ENOMEM;
-	table = page_to_virt(page);
-	memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));
+
+	table = memcpy(page_to_virt(page), gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));

 	/* Set new table origin while preserving existing ASCE control bits */
 	asce = (gmap->asce & ~_ASCE_ORIGIN) | __pa(table);
-- 
2.51.1

Re: [PATCH] s390/mm: Use pointer from memcpy() call for assignment in s390_replace_asce()

Posted by Claudio Imbrenda 3 months ago

On Fri, 31 Oct 2025 08:22:30 +0100
Markus Elfring <Markus.Elfring@web.de> wrote:

> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Fri, 31 Oct 2025 07:56:06 +0100
> 
> A pointer was assigned to a variable. The same pointer was used for
> the destination parameter of a memcpy() call.
> This function is documented in the way that the same value is returned.
> Thus convert two separate statements into a direct variable assignment for
> the return value from a memory copy action.
> 
> The source code was transformed by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  arch/s390/mm/gmap.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 22c448b32340..e49e839933f1 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -2440,8 +2440,8 @@ int s390_replace_asce(struct gmap *gmap)
>  	page = gmap_alloc_crst();
>  	if (!page)
>  		return -ENOMEM;
> -	table = page_to_virt(page);
> -	memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));
> +
> +	table = memcpy(page_to_virt(page), gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));
>  
>  	/* Set new table origin while preserving existing ASCE control bits */
>  	asce = (gmap->asce & ~_ASCE_ORIGIN) | __pa(table);

NACK

1) the change makes the code less readable / understandable
2) mm/gmap.c is going away soon