[PATCH v1 1/1] nfsd: Mark variable __maybe_unused to avoid W=1 build break

[PATCH v1 1/1] nfsd: Mark variable __maybe_unused to avoid W=1 build break

[Andy Shevchenko]

Clang is not happy about set but (in some cases) unused variable:

fs/nfsd/export.c:1027:17: error: variable 'inode' set but not used [-Werror,-Wunused-but-set-variable]

since it's used as a parameter to dprintk() which might be configured
a no-op. To avoid uglifying code with the specific ifdeffery just mark
the variable __maybe_unused.

The commit [1], which introduced this behaviour, is quite old and hence
the Fixes tag points to the first of Git era.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=0431923fb7a1 [1]
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 fs/nfsd/export.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 9d55512d0cc9..2a1499f2ad19 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -1024,7 +1024,7 @@ exp_rootfh(struct net *net, struct auth_domain *clp, char *name,
 {
 	struct svc_export	*exp;
 	struct path		path;
-	struct inode		*inode;
+	struct inode		*inode __maybe_unused;
 	struct svc_fh		fh;
 	int			err;
 	struct nfsd_net		*nn = net_generic(net, nfsd_net_id);
-- 
2.50.1

Re: [PATCH v1 1/1] nfsd: Mark variable __maybe_unused to avoid W=1 build break

[Chuck Lever]

On 11/13/25 3:31 AM, Andy Shevchenko wrote:
> Clang is not happy about set but (in some cases) unused variable:
> 
> fs/nfsd/export.c:1027:17: error: variable 'inode' set but not used [-Werror,-Wunused-but-set-variable]
> 
> since it's used as a parameter to dprintk() which might be configured
> a no-op. To avoid uglifying code with the specific ifdeffery just mark
> the variable __maybe_unused.
> 
> The commit [1], which introduced this behaviour, is quite old and hence
> the Fixes tag points to the first of Git era.
> 
> Link: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=0431923fb7a1 [1]
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  fs/nfsd/export.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
> index 9d55512d0cc9..2a1499f2ad19 100644
> --- a/fs/nfsd/export.c
> +++ b/fs/nfsd/export.c
> @@ -1024,7 +1024,7 @@ exp_rootfh(struct net *net, struct auth_domain *clp, char *name,
>  {
>  	struct svc_export	*exp;
>  	struct path		path;
> -	struct inode		*inode;
> +	struct inode		*inode __maybe_unused;

We typically use "#ifdef CONFIG_SUNRPC_DEBUG" instead for this purpose.
I don't think that would be terribly out of place.


>  	struct svc_fh		fh;
>  	int			err;
>  	struct nfsd_net		*nn = net_generic(net, nfsd_net_id);


-- 
Chuck Lever

Re: [PATCH v1 1/1] nfsd: Mark variable __maybe_unused to avoid W=1 build break

[Chuck Lever]

From: Chuck Lever <chuck.lever@oracle.com>

On Thu, 13 Nov 2025 09:31:31 +0100, Andy Shevchenko wrote:
> Clang is not happy about set but (in some cases) unused variable:
> 
> fs/nfsd/export.c:1027:17: error: variable 'inode' set but not used [-Werror,-Wunused-but-set-variable]
> 
> since it's used as a parameter to dprintk() which might be configured
> a no-op. To avoid uglifying code with the specific ifdeffery just mark
> the variable __maybe_unused.
> 
> [...]

Applied to nfsd-testing, thanks!

[1/1] nfsd: Mark variable __maybe_unused to avoid W=1 build break
      commit: 56e9f88b25abf08de6f2b1bfbbb2ddc4e6622d1e

--
Chuck Lever