xfs: use kmalloc_array() instead of kmalloc() for map allocation

[PATCH] xfs: use kmalloc_array() instead of kmalloc() for map allocation

Posted by Kriish Sharma 3 months, 3 weeks ago

Using kmalloc_array() better reflects the intent to allocate an array of
map entries, and improves consistency with similar allocations across the
kernel.

No functional change intended.

Signed-off-by: Kriish Sharma <kriish.sharma2006@gmail.com>
---
 fs/xfs/xfs_qm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 23ba84ec919a..34ec61e455ff 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1218,7 +1218,7 @@ xfs_qm_reset_dqcounts_buf(
 	if (qip->i_nblocks == 0)
 		return 0;
 
-	map = kmalloc(XFS_DQITER_MAP_SIZE * sizeof(*map),
+	map = kmalloc_array(XFS_DQITER_MAP_SIZE, sizeof(*map),
 			GFP_KERNEL | __GFP_NOFAIL);
 
 	lblkno = 0;
-- 
2.34.1

Re: [PATCH] xfs: use kmalloc_array() instead of kmalloc() for map allocation

Posted by Darrick J. Wong 3 months, 2 weeks ago

On Sat, Oct 18, 2025 at 07:45:28PM +0000, Kriish Sharma wrote:
> Using kmalloc_array() better reflects the intent to allocate an array of
> map entries, and improves consistency with similar allocations across the
> kernel.
> 
> No functional change intended.
> 
> Signed-off-by: Kriish Sharma <kriish.sharma2006@gmail.com>
> ---
>  fs/xfs/xfs_qm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
> index 23ba84ec919a..34ec61e455ff 100644
> --- a/fs/xfs/xfs_qm.c
> +++ b/fs/xfs/xfs_qm.c
> @@ -1218,7 +1218,7 @@ xfs_qm_reset_dqcounts_buf(
>  	if (qip->i_nblocks == 0)
>  		return 0;
>  
> -	map = kmalloc(XFS_DQITER_MAP_SIZE * sizeof(*map),
> +	map = kmalloc_array(XFS_DQITER_MAP_SIZE, sizeof(*map),

Why would we replace a constant that can be computed at compile time
with a dynamic computation that is now fallible despite NOFAIL?

--D

>  			GFP_KERNEL | __GFP_NOFAIL);
>  
>  	lblkno = 0;
> -- 
> 2.34.1
> 
>

Re: [PATCH] xfs: use kmalloc_array() instead of kmalloc() for map allocation

Posted by Carlos Maiolino 3 months, 2 weeks ago

Hello.

On Sat, Oct 18, 2025 at 07:45:28PM +0000, Kriish Sharma wrote:
> Using kmalloc_array() better reflects the intent to allocate an array of
> map entries, and improves consistency with similar allocations across the
> kernel.
> 
> No functional change intended.

Thanks for the patch.
Have you ran xfstests against this patch? All patches sent to xfs should
at least pass basic testing via xfstests. I.e. ensure there is no new
failure between an unpatched kernel and a kernel with your patch.

If you did, please send me the results summary, if you did not, please
run it, and send a V2 of this patch  including in the patch description
the summary of the results.

Any changes includes risk, and so every patch sent to xfs should be at
least basically tested against xfstests auto group.

Thanks,
Carlos

> 
> Signed-off-by: Kriish Sharma <kriish.sharma2006@gmail.com>
> ---
>  fs/xfs/xfs_qm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
> index 23ba84ec919a..34ec61e455ff 100644
> --- a/fs/xfs/xfs_qm.c
> +++ b/fs/xfs/xfs_qm.c
> @@ -1218,7 +1218,7 @@ xfs_qm_reset_dqcounts_buf(
>  	if (qip->i_nblocks == 0)
>  		return 0;
> 
> -	map = kmalloc(XFS_DQITER_MAP_SIZE * sizeof(*map),
> +	map = kmalloc_array(XFS_DQITER_MAP_SIZE, sizeof(*map),
>  			GFP_KERNEL | __GFP_NOFAIL);
> 
>  	lblkno = 0;
> --
> 2.34.1
>