[PATCH] fs: quota: avoid unused function warning for !CONFIG_SYSCTL

[PATCH] fs: quota: avoid unused function warning for !CONFIG_SYSCTL

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

Having fs_dqstats_table[] inside of an #ifdef causes a build time
warning:

fs/quota/dquot.c:2864:12: error: 'do_proc_dqstats' defined but not used [-Werror=unused-function]
 2864 | static int do_proc_dqstats(struct ctl_table *table, int write,

Avoid this by using an IS_ENABLED() check in place of the #ifdef,
giving the compiler a better idea of how it is used.

Fixes: 63d00e08515b ("quota: check for register_sysctl() failure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
Note: it may be better to just revert the 63d00e08515b patch, as the
additional pr_notice() does not seem to add much value after
the pr_err() printed by register_sysctl() that tells us exactly what
went wrong.
---
 fs/quota/dquot.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 05bed02b257f..6e9109c6218e 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2877,7 +2877,6 @@ static int do_proc_dqstats(struct ctl_table *table, int write,
 	return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 }
 
-#ifdef CONFIG_SYSCTL
 static struct ctl_table fs_dqstats_table[] = {
 	{
 		.procname	= "lookups",
@@ -2946,7 +2945,6 @@ static struct ctl_table fs_dqstats_table[] = {
 #endif
 	{ },
 };
-#endif
 
 static int __init dquot_init(void)
 {
@@ -2955,10 +2953,10 @@ static int __init dquot_init(void)
 
 	printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
 
-#ifdef CONFIG_SYSCTL
-	if (!register_sysctl("fs/quota", fs_dqstats_table))
-		pr_notice("quota sysctl registration failed!\n");
-#endif
+	if (IS_ENABLED(CONFIG_SYSCTL)) {
+		if (!register_sysctl("fs/quota", fs_dqstats_table))
+			pr_notice("quota sysctl registration failed!\n");
+	}
 
 	dquot_cachep = kmem_cache_create("dquot",
 			sizeof(struct dquot), sizeof(unsigned long) * 4,
-- 
2.39.2

Re: [PATCH] fs: quota: avoid unused function warning for !CONFIG_SYSCTL

[Luis Chamberlain]

On Tue, Mar 28, 2023 at 02:22:31PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> Note: it may be better to just revert the 63d00e08515b patch, as the
> -#ifdef CONFIG_SYSCTL
> -	if (!register_sysctl("fs/quota", fs_dqstats_table))
> -		pr_notice("quota sysctl registration failed!\n");
> -#endif
> +	if (IS_ENABLED(CONFIG_SYSCTL)) {
> +		if (!register_sysctl("fs/quota", fs_dqstats_table))
> +			pr_notice("quota sysctl registration failed!\n");
> +	}

I'd agree to drop that patch and instead just use register_sysctl_init()
iwht Arnd's strategy.

  Luis

Re: [PATCH] fs: quota: avoid unused function warning for !CONFIG_SYSCTL

[Jan Kara]

On Tue 28-03-23 10:48:20, Luis Chamberlain wrote:
> On Tue, Mar 28, 2023 at 02:22:31PM +0200, Arnd Bergmann wrote:
> > From: Arnd Bergmann <arnd@arndb.de>
> > Note: it may be better to just revert the 63d00e08515b patch, as the
> > -#ifdef CONFIG_SYSCTL
> > -	if (!register_sysctl("fs/quota", fs_dqstats_table))
> > -		pr_notice("quota sysctl registration failed!\n");
> > -#endif
> > +	if (IS_ENABLED(CONFIG_SYSCTL)) {
> > +		if (!register_sysctl("fs/quota", fs_dqstats_table))
> > +			pr_notice("quota sysctl registration failed!\n");
> > +	}
> 
> I'd agree to drop that patch and instead just use register_sysctl_init()
> iwht Arnd's strategy.

Ah, indeed, register_sysctl_init() is exactly what we need here. I didn't
know about that helper. Thanks for letting me know.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR