Subject: [PATCH v6 0/2] Fix compiler warnings/errors in SUNRPC and MACB

From: Sean Chang <[email-masked]>
Date: Mon, 2 Mar 2026 00:17:07 +0800

This series addresses compiler warnings and a build error identified across 
different architectures and configurations.

The first patch refactors the dfprintk macros in the SUNRPC subsystem. This 
global fix silences unused variable warnings and, by incorporating 
no_printk(), ensures continued compiler type checking. It also includes 
a specific fix for a build error in nfsd (nfsfh.c) uncovered by syzbot 
in non-debug configurations.

The second patch fixes a format-truncation warning in the MACB ethernet
driver by ensuring the snprintf output fits within the destination buffer.

v6:
- Instead of wrapping dprintk in #if blocks, completely remove the 
  redundant RPC_IFDEBUG() macro and associated #if guards in nfsfh.c and 
  svc_rdma_transport.c.
- Remove the #if guard around the static helper nlmdbg_cookie2a() in 
  svclock.c.
- Verified via .lst and nm that both variables (buf) and helper functions 
  (nlmdbg_cookie2a) are fully optimized out by the compiler when 
  CONFIG_SUNRPC_DEBUG is disabled.

v5:
- Simplify dfprintk and dfprintk_rcu macros by removing the redundant 'fmt' 
  argument and calling no_printk(__VA_ARGS__) directly, as suggested by 
  David Laight.
- Fix a build error in fs/nfsd/nfsfh.c reported by syzbot. The error was 
  caused by a mismatch between the variable's lifecycle (defined via 
  RPC_IFDEBUG) and its usage in dprintk.
- Add Link tag to the syzbot build failure report.
- Update series title to reflect the general nature of the fixes.

v4:
- Refactor patch 1 to use no_printk() in sunrpc headers instead of marking
  variables as __maybe_unused. This provides a cleaner, global fix and
  enables compiler type checking.

v3:
- Expand commit descriptions to include technical details regarding macro
  expansion, as requested by Andrew Lunn.
- Test the different platform, such as ARM, ARM64, X86_64.

v2:
- Split the original treewide patch into subsystem-specific commits.
- Added more detailed commit descriptions to satisfy checkpatch.

Sean Chang (2):
  sunrpc: simplify dprintk macros and cleanup redundant debug guards
  net: macb: use ethtool_sprintf to fill ethtool stats strings

 drivers/net/ethernet/cadence/macb_main.c | 7 ++-----
 fs/lockd/svclock.c                       | 2 --
 fs/nfsd/nfsfh.c                          | 2 +-
 include/linux/sunrpc/debug.h             | 6 ++----
 net/sunrpc/xprtrdma/svc_rdma_transport.c | 4 +---
 5 files changed, 6 insertions(+), 15 deletions(-)

-- 
2.34.1