Re: [PATCH] fs, coda: Fix compile warning when CONFIG_SYSCTL=n.

[Andrew Morton <akpm@linux-foundation.org>]

On Sun, 13 Mar 2011 21:48:23 +0600
Rakib Mullick <rakib.mullick@gmail.com> wrote:

> When CONFIG_SYSCTL=n, we get the following warning:
> 
> fs/coda/sysctl.c:18: warning: ___coda_table___ defined but not used
> 
> Following patches fixes the above warning by making sure coda_table
> and it's callee
> function are in the same context. It also cleans up the code by
> removing extra #ifdef.
> 
> ...
>
> --- a/fs/coda/sysctl.c
> +++ b/fs/coda/sysctl.c
>
> ...
>
> +#else
> +
> +#define	coda_sysctl_init()		do { }  while (0);
> +#define	coda_sysctl_clean()		do { }	while (0);
> +
> +#endif

These do/while stubs should not have the trailing ";" - adding them
will cause breakage in some calling scenarios.

It is much better to implement such stubs in C rather than as macros.

But these stubs can't be doing anything useful anyway: they appear at
the end of a .c file which wasn't #included by anything.  Therefore:

--- a/fs/coda/sysctl.c~fs-coda-fix-compile-warning-when-config_sysctl=n-fix
+++ a/fs/coda/sysctl.c
@@ -61,9 +61,4 @@ void coda_sysctl_clean(void)
 		fs_table_header = NULL;
 	}
 }
-#else
-
-#define	coda_sysctl_init()		do { }  while (0);
-#define	coda_sysctl_clean()		do { }	while (0);
-
 #endif
_