Re: [PATCH v2] sunrpc: simplify dprintk() macros and cleanup redundant debug guards

Following David Laight's suggestion, simplify the macro definitions by
removing the unnecessary 'fmt' argument and using no_printk(__VA_ARGS__)
directly.

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().

Suggested-by: Andrew Lunn <andrew@lunn.ch>
Suggested-by: David Laight <redacted>
Signed-off-by: Sean Chang <redacted>
---
v2:
 - Follow reversed xmas tree order for variables in svc_rdma_transport.c
   as requested by Andy Shevchenko.
 - Polish commit message: use dprintk() and remove redundant file list.
 - Correct the technical claim about dprintk() type checking.

 fs/lockd/svclock.c                       |  7 -------
 fs/nfsd/nfsfh.c                          |  8 +++-----
 include/linux/sunrpc/debug.h             |  8 ++------
 net/sunrpc/xprtrdma/svc_rdma_transport.c | 25 +++++++++++-------------
 4 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index ee23f5802af1..9b978a087b3c 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c

@@ -47,7 +47,6 @@ 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)
 {
 	/*

@@ -74,12 +73,6 @@ static const char *nlmdbg_cookie2a(const struct 

nlm_cookie *cookie)

 	return buf;
 }
-#else
-static inline const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie)
-{
-	return "???";
-}
-#endif

 /*
  * Insert a blocked lock into the global list

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 68b629fbaaeb..91514326d1b4 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c

@@ -105,12 +105,10 @@ 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)) {
-		if (IS_ENABLED(CONFIG_SUNRPC_DEBUG)) {
-			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)));
-		}
+		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 ab61bed2f7af..f6f2a106eeaf 100644
--- a/include/linux/sunrpc/debug.h
+++ b/include/linux/sunrpc/debug.h

@@ -38,8 +38,6 @@ extern unsigned int		nlm_debug;
 do {									\
 	ifdebug(fac)							\
 		__sunrpc_printk(fmt, ##__VA_ARGS__);			\
-	else								\
-		no_printk(fmt, ##__VA_ARGS__);				\
 } while (0)

 # define dfprintk_rcu(fac, fmt, ...)					\

@@ -48,15 +46,13 @@ do {									\
 		rcu_read_lock();					\
 		__sunrpc_printk(fmt, ##__VA_ARGS__);			\
 		rcu_read_unlock();					\
-	} else {							\
-		no_printk(fmt, ##__VA_ARGS__);				\
 	}								\
 } while (0)

 #else
 # define ifdebug(fac)		if (0)
-# define dfprintk(fac, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
-# define dfprintk_rcu(fac, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
+# 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 f2d72181a6fe..0759444bda50 100644

--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c

@@ -413,6 +413,7 @@ static struct svc_xprt *svc_rdma_accept(struct 

svc_xprt *xprt)
 	struct rpcrdma_connect_private pmsg;
 	struct ib_qp_init_attr qp_attr;
 	struct ib_device *dev;
+	struct sockaddr *sap;
 	int ret = 0;

 	listen_rdma = container_of(xprt, struct svcxprt_rdma, sc_xprt);

@@ -559,20 +560,16 @@ static struct svc_xprt *svc_rdma_accept(struct 

svc_xprt *xprt)
 		goto errout;
 	}

-	if (IS_ENABLED(CONFIG_SUNRPC_DEBUG)) {
-		struct sockaddr *sap;
-
-		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));
-		sap = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
-		dprintk("    remote address  : %pIS:%u\n", sap, rpc_get_port(sap));
-		dprintk("    max_sge         : %d\n", newxprt->sc_max_send_sges);
-		dprintk("    sq_depth        : %d\n", newxprt->sc_sq_depth);
-		dprintk("    rdma_rw_ctxs    : %d\n", ctxts);
-		dprintk("    max_requests    : %d\n", newxprt->sc_max_requests);
-		dprintk("    ord             : %d\n", conn_param.initiator_depth);
-	}
+	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));
+	sap = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.dst_addr;
+	dprintk("    remote address  : %pIS:%u\n", sap, rpc_get_port(sap));
+	dprintk("    max_sge         : %d\n", newxprt->sc_max_send_sges);
+	dprintk("    sq_depth        : %d\n", newxprt->sc_sq_depth);
+	dprintk("    rdma_rw_ctxs    : %d\n", ctxts);
+	dprintk("    max_requests    : %d\n", newxprt->sc_max_requests);
+	dprintk("    ord             : %d\n", conn_param.initiator_depth);

 	return &newxprt->sc_xprt;

-- 
2.34.1