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

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