linux-kernel - Re: [PATCH v1 1/1] sunrpc: Fix compilation error (`make W=1`) when dprintk() is no-op

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Message-ID: <CAMuHMdWZx=2-y_OSjCkxmXo-3YjGjU0aH89puTcL0rmvw7E-Eg@mail.gmail.com>
Date: Wed, 4 Feb 2026 08:53:39 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Chuck Lever <chuck.lever@...cle.com>, NeilBrown <neil@...wn.name>, 
	Jeff Layton <jlayton@...nel.org>, linux-nfs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, llvm@...ts.linux.dev, 
	Olga Kornievskaia <okorniev@...hat.com>, Dai Ngo <Dai.Ngo@...cle.com>, Tom Talpey <tom@...pey.com>, 
	Trond Myklebust <trondmy@...nel.org>, Anna Schumaker <anna@...nel.org>, 
	Nathan Chancellor <nathan@...nel.org>, Nick Desaulniers <nick.desaulniers+lkml@...il.com>, 
	Bill Wendling <morbo@...gle.com>, Justin Stitt <justinstitt@...gle.com>
Subject: Re: [PATCH v1 1/1] sunrpc: Fix compilation error (`make W=1`) when
 dprintk() is no-op

Hi Andy,

On Wed, 4 Feb 2026 at 02:11, Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
> On Wed, Feb 04, 2026 at 02:04:15AM +0100, Andy Shevchenko wrote:
> > Clang compiler is not happy about set but unused variables:
> >
> > .../flexfilelayout/flexfilelayoutdev.c:56:9: error: variable 'ret' set but not used [-Werror,-Wunused-but-set-variable]
> > .../flexfilelayout/flexfilelayout.c:1505:6: error: variable 'err' set but not used [-Werror,-Wunused-but-set-variable]
> > .../nfs4proc.c:9244:12: error: variable 'ptr' set but not used [-Werror,-Wunused-but-set-variable]
> >
> > Fix these by forwarding parameters of dprintk() to no_printk().
> > The positive side-effect is a format-string checker enabled even for the cases
> > when dprintk() is no-op.
>
> Note, the alternative fix is to add __maybe_unused all over the place.
> With pros and cons I consider my approach better.

Definitely.  I tried something similar a few years ago[1], but ran into build
errors from the robots, and gave up due to lack of time.

So for the principle:
Acked-by: Geert Uytterhoeven <geert+renesas@...der.be>

Ah, my local tree still has the following fix I never sent out, and still
looks suboptimal:

--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -105,9 +105,11 @@ static __be32 nfsd_setuser_and_check_port(struct
svc_rqst *rqstp,
 {
        /* Check if the request originated from a secure port. */
        if (rqstp && !nfsd_originating_port_ok(rqstp, cred, exp)) {
-               RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
+#ifdef CONFIG_SUNRPC_DEBUG
+               char buf[RPC_MAX_ADDRBUFLEN];
                dprintk("nfsd: request from insecure port %s!\n",
                        svc_print_addr(rqstp, buf, sizeof(buf)));
+#endif
                return nfserr_perm;
        }

[1]  https://lore.kernel.org/a93de2e8afa826745746b00fc5f64e513df5d52f.1697104757.git.geert+renesas@glider.be

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds