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

From: Sean Chang

Date: Sun Mar 01 2026 - 11:17:36 EST


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