[PATCH] sysctl: quiet unused variable warning in fs/proc/proc_sysctl.c:init_header()

[PATCH] sysctl: quiet unused variable warning in fs/proc/proc_sysctl.c:init_header()

[Ethan Nelson-Moore]

The init_header() function uses list_for_each_table_entry() without
using the entry argument. This causes a warning when building with W=1.
Since the code is correct, mark the associated variable as
__maybe_unused.

Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
---
 fs/proc/proc_sysctl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 04a382178c65..d0d76c31d330 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -206,7 +206,7 @@ static void init_header(struct ctl_table_header *head,
 	head->node = node;
 	INIT_HLIST_HEAD(&head->inodes);
 	if (node) {
-		const struct ctl_table *entry;
+		const struct ctl_table *entry __maybe_unused;
 
 		list_for_each_table_entry(entry, head) {
 			node->header = head;
-- 
2.43.0

Re: [PATCH] sysctl: quiet unused variable warning in fs/proc/proc_sysctl.c:init_header()

[Joel Granados]

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On Thu, Sep 17, 2026 at 11:23:38PM -0700, Ethan Nelson-Moore wrote:
> The init_header() function uses list_for_each_table_entry() without
> using the entry argument. This causes a warning when building with W=1.
> Since the code is correct, mark the associated variable as
> __maybe_unused.

I'm probably compiling in a different way but I don't see that warning.
Can you please tell me how you compile, what are you are in. What
version of compiler are you running?

Thx
> 
> Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
> ---
>  fs/proc/proc_sysctl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
> index 04a382178c65..d0d76c31d330 100644
> --- a/fs/proc/proc_sysctl.c
> +++ b/fs/proc/proc_sysctl.c
> @@ -206,7 +206,7 @@ static void init_header(struct ctl_table_header *head,
>  	head->node = node;
>  	INIT_HLIST_HEAD(&head->inodes);
>  	if (node) {
> -		const struct ctl_table *entry;
> +		const struct ctl_table *entry __maybe_unused;
>  
>  		list_for_each_table_entry(entry, head) {
>  			node->header = head;
> -- 
> 2.43.0
> 

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Re: [PATCH] sysctl: quiet unused variable warning in fs/proc/proc_sysctl.c:init_header()

[Ethan Nelson-Moore]

Hi, Joel,

On Fri, Sep 18, 2026 at 4:05 AM Joel Granados <joel.granados@kernel.org> wrote:
> I'm probably compiling in a different way but I don't see that warning.
> Can you please tell me how you compile, what are you are in. What
> version of compiler are you running?

I'm using GCC 16.2, which probably explains it, since newer GCC
versions have gotten more clever at detecting unused variables.

Ethan

Re: [PATCH] sysctl: quiet unused variable warning in fs/proc/proc_sysctl.c:init_header()

[Joel Granados]

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On Sat, Sep 19, 2026 at 03:58:43PM -0700, Ethan Nelson-Moore wrote:
> Hi, Joel,
> 
> On Fri, Sep 18, 2026 at 4:05 AM Joel Granados <joel.granados@kernel.org> wrote:
> > I'm probably compiling in a different way but I don't see that warning.
> > Can you please tell me how you compile, what are you are in. What
> > version of compiler are you running?
> 
> I'm using GCC 16.2, which probably explains it, since newer GCC
> versions have gotten more clever at detecting unused variables.

I'll add it to sysctl-next

best

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