Re: [PATCH v6 1/2] sunrpc: simplify dprintk macros and cleanup redundant debug guards

[Andy Shevchenko]

On Mon, Mar 02, 2026 at 12:17:08AM +0800, Sean Chang wrote:
> When CONFIG_SUNRPC_DEBUG is disabled, the dfprintk() macros currently
> expand to empty do-while loops. This causes variables used solely
> within these calls to appear unused, triggering -Wunused-variable
> warnings.
> 
> Following David Laight's suggestion, simplify the macro definitions by
> removing the unnecessary 'fmt' argument and using no_printk(__VA_ARGS__)
> directly. This ensures the compiler performs type checking and "sees"
> the variables, silencing the warnings without emitting any code.
> 
> Verification with .lst files under -O2 confirms that the compiler
> successfully performs "dead code elimination". Even when variables
> (like char buf[] in nfsfh.c) or static helper functions (like
> nlmdbg_cookie2a in svclock.c) are declared without #ifdef, they are
> completely optimized out (no stack allocation, no symbol references in
> the final executable) as they are only referenced within no_printk().
> 
> This allows for significant cleanup:
> - Remove RPC_IFDEBUG() and associated #if blocks in fs/nfsd/nfsfh.c
>   and net/sunrpc/xprtrdma/svc_rdma_transport.c.
> - Remove the #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) guard around
>   nlmdbg_cookie2a in fs/lockd/svclock.c.
> - Consolidate the dprintk definition to be more idiomatic.
> 
> This fixes the build errors reported by the kernel test robot while
> improving code maintainability.

If you feel something has to be done against nfsd-next, please rebase and send
as a standalone patch.

-- 
With Best Regards,
Andy Shevchenko