thermal/debugfs: replace kzalloc() with kcalloc() in thermal_debug_tz_add()

[PATCH] thermal/debugfs: replace kzalloc() with kcalloc() in thermal_debug_tz_add()

Posted by Ethan Carter Edwards 11 months, 2 weeks ago

We are trying to get rid of all multiplications from allocation
functions to prevent integer overflows[1]. Here the multiplication is
obviously safe, but using kcalloc() is more appropriate and improves
readability. This patch has no effect on runtime behavior.

Link: https://github.com/KSPP/linux/issues/162 [1]
Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

Signed-off-by: Ethan Carter Edwards <ethan@ethancedwards.com>
---
 drivers/thermal/thermal_debugfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_debugfs.c b/drivers/thermal/thermal_debugfs.c
index c800504c3cfe0ea3b4a51286f348dd5802e1898f..60ee6c366998e26447a0b985112f578ba8757f17 100644
--- a/drivers/thermal/thermal_debugfs.c
+++ b/drivers/thermal/thermal_debugfs.c
@@ -876,7 +876,7 @@ void thermal_debug_tz_add(struct thermal_zone_device *tz)
 
 	tz_dbg->tz = tz;
 
-	tz_dbg->trips_crossed = kzalloc(sizeof(int) * tz->num_trips, GFP_KERNEL);
+	tz_dbg->trips_crossed = kcalloc(tz->num_trips, sizeof(int), GFP_KERNEL);
 	if (!tz_dbg->trips_crossed) {
 		thermal_debugfs_remove_id(thermal_dbg);
 		return;

---
base-commit: 5cf80612d3f72c46ad53ef5042b4c609c393122f
change-id: 20250222-thermal_kcalloc-881dcf5b77b8

Best regards,
-- 
Ethan Carter Edwards <ethan@ethancedwards.com>

Re: [PATCH] thermal/debugfs: replace kzalloc() with kcalloc() in thermal_debug_tz_add()

Posted by Rafael J. Wysocki 11 months, 2 weeks ago

On Sat, Feb 22, 2025 at 9:02 PM Ethan Carter Edwards
<ethan@ethancedwards.com> wrote:
>
> We are trying to get rid of all multiplications from allocation
> functions to prevent integer overflows[1]. Here the multiplication is
> obviously safe, but using kcalloc() is more appropriate and improves
> readability. This patch has no effect on runtime behavior.
>
> Link: https://github.com/KSPP/linux/issues/162 [1]
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
>
> Signed-off-by: Ethan Carter Edwards <ethan@ethancedwards.com>
> ---
>  drivers/thermal/thermal_debugfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/thermal_debugfs.c b/drivers/thermal/thermal_debugfs.c
> index c800504c3cfe0ea3b4a51286f348dd5802e1898f..60ee6c366998e26447a0b985112f578ba8757f17 100644
> --- a/drivers/thermal/thermal_debugfs.c
> +++ b/drivers/thermal/thermal_debugfs.c
> @@ -876,7 +876,7 @@ void thermal_debug_tz_add(struct thermal_zone_device *tz)
>
>         tz_dbg->tz = tz;
>
> -       tz_dbg->trips_crossed = kzalloc(sizeof(int) * tz->num_trips, GFP_KERNEL);
> +       tz_dbg->trips_crossed = kcalloc(tz->num_trips, sizeof(int), GFP_KERNEL);
>         if (!tz_dbg->trips_crossed) {
>                 thermal_debugfs_remove_id(thermal_dbg);
>                 return;
>
> ---

Applied as 6.15 material with some edits in the changelog, thanks!

Re: [PATCH] thermal/debugfs: replace kzalloc() with kcalloc() in thermal_debug_tz_add()

Posted by Lukasz Luba 11 months, 2 weeks ago


On 2/22/25 20:02, Ethan Carter Edwards wrote:
> We are trying to get rid of all multiplications from allocation
> functions to prevent integer overflows[1]. Here the multiplication is
> obviously safe, but using kcalloc() is more appropriate and improves
> readability. This patch has no effect on runtime behavior.
> 
> Link: https://github.com/KSPP/linux/issues/162 [1]
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
> 


IMO there is no need for such links in the patch header.
The explanation is enough. Just drop those two links
and should be good.

Thanks for the patch!

Regards,
Lukasz

Re: [PATCH v4?] thermal/debugfs: replace kzalloc() with kcalloc() in thermal_debug_tz_add()

Posted by Markus Elfring 11 months, 2 weeks ago

…
> We are trying to get rid of all multiplications from allocation
> functions to prevent integer overflows[1]. …

Is an imperative wording more desirable for such a change description?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.14-rc3#n94


…
> ---
>  drivers/thermal/thermal_debugfs.c | 2 +-
…

How do you think about to improve your version management?
https://lore.kernel.org/all/?q=%22This+looks+like+a+new+version+of+a+previously+submitted+patch%22
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.14-rc3#n780


…
> +++ b/drivers/thermal/thermal_debugfs.c
> @@ -876,7 +876,7 @@ void thermal_debug_tz_add(struct thermal_zone_device *tz)
>
>  	tz_dbg->tz = tz;
>
> -	tz_dbg->trips_crossed = kzalloc(sizeof(int) * tz->num_trips, GFP_KERNEL);
> +	tz_dbg->trips_crossed = kcalloc(tz->num_trips, sizeof(int), GFP_KERNEL);
…

See also:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?h=v6.14-rc3#n941

Regards,
Markus