[PATCH v6 1/2] sunrpc: simplify dprintk macros and cleanup redundant debug guards
From: Sean Chang <hidden>
Date: 2026-03-01 16:17:29
Also in:
linux-nfs, lkml
Subsystem:
filesystems (vfs and infrastructure), kernel nfsd, sunrpc, and lockd servers, networking [general], nfs, sunrpc, and lockd clients, the rest · Maintainers:
Alexander Viro, Christian Brauner, Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, Linus Torvalds
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. Link: https://lore.kernel.org/all/69a2e269.050a0220.3a55be.003e.GAE@google.com/ (local) Reported-by: kernel test robot <redacted> Closes: https://lore.kernel.org/oe-kbuild-all/202603010612.uRmHYMsi-lkp@intel.com/ (local) Closes: https://lore.kernel.org/oe-kbuild-all/202603010852.3RKXCwyF-lkp@intel.com/ (local) Closes: https://lore.kernel.org/oe-kbuild-all/202603010808.w3TtG6fC-lkp@intel.com/ (local) Suggested-by: Andrew Lunn <andrew@lunn.ch> Suggested-by: David Laight <redacted> Signed-off-by: Sean Chang <redacted> --- fs/lockd/svclock.c | 2 -- fs/nfsd/nfsfh.c | 2 +- include/linux/sunrpc/debug.h | 6 ++---- net/sunrpc/xprtrdma/svc_rdma_transport.c | 4 +--- 4 files changed, 4 insertions(+), 10 deletions(-)
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 255a847ca0b6..4bac32f009f6 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c@@ -53,7 +53,6 @@ static const struct rpc_call_ops nlmsvc_grant_ops; static LIST_HEAD(nlm_blocked); static DEFINE_SPINLOCK(nlm_blocked_lock); -#if IS_ENABLED(CONFIG_SUNRPC_DEBUG) static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie) { /*
@@ -80,7 +79,6 @@ static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie) return buf; } -#endif /* * Insert a blocked lock into the global list
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index ed85dd43da18..cb3fb91d18c0 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c@@ -105,7 +105,7 @@ 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]); + char buf[RPC_MAX_ADDRBUFLEN]; dprintk("nfsd: request from insecure port %s!\n", svc_print_addr(rqstp, buf, sizeof(buf))); return nfserr_perm;
diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
index eb4bd62df319..f6f2a106eeaf 100644
--- a/include/linux/sunrpc/debug.h
+++ b/include/linux/sunrpc/debug.h@@ -49,12 +49,10 @@ do { \ } \ } while (0) -# define RPC_IFDEBUG(x) x #else # define ifdebug(fac) if (0) -# define dfprintk(fac, fmt, ...) do {} while (0) -# define dfprintk_rcu(fac, fmt, ...) do {} while (0) -# define RPC_IFDEBUG(x) +# define dfprintk(fac, ...) no_printk(__VA_ARGS__) +# define dfprintk_rcu(fac, ...) no_printk(__VA_ARGS__) #endif /*
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 9b623849723e..ba6fe0fd387d 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c@@ -414,7 +414,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) struct ib_qp_init_attr qp_attr; struct ib_device *dev; int ret = 0; - RPC_IFDEBUG(struct sockaddr *sap); + struct sockaddr *sap; listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt); clear_bit(XPT_CONN, &xprt->xpt_flags);
@@ -560,7 +560,6 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) goto errout; } -#if IS_ENABLED(CONFIG_SUNRPC_DEBUG) dprintk("svcrdma: new connection accepted on device %s:\n", dev->name); sap = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr; dprintk(" local address : %pIS:%u\n", sap, rpc_get_port(sap));
@@ -571,7 +570,6 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) dprintk(" rdma_rw_ctxs : %d\n", ctxts); dprintk(" max_requests : %d\n", newxprt->sc_max_requests); dprintk(" ord : %d\n", conn_param.initiator_depth); -#endif return &newxprt->sc_xprt;
--
2.34.1