linux-kernel - [PATCH 4/4] ceph: Use no

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Message-Id: <a21767eccb823435a7f18cdf115d7d572b4e945d.1709127473.git.geert+renesas@glider.be>
Date: Wed, 28 Feb 2024 15:00:05 +0100
From: Geert Uytterhoeven <geert+renesas@...der.be>
To: Chris Down <chris@...isdown.name>,
	Petr Mladek <pmladek@...e.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Jessica Yu <jeyu@...nel.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	John Ogness <john.ogness@...utronix.de>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	Jason Baron <jbaron@...mai.com>,
	Jim Cromie <jim.cromie@...il.com>,
	Ilya Dryomov <idryomov@...il.com>,
	Xiubo Li <xiubli@...hat.com>,
	Jeff Layton <jlayton@...nel.org>
Cc: linux-kernel@...r.kernel.org,
	ceph-devel@...r.kernel.org,
	Geert Uytterhoeven <geert+renesas@...der.be>
Subject: [PATCH 4/4] ceph: Use no_printk() helper

When printk-indexing is enabled, each printk() invocation emits a
pi_entry structure.  This is even true when the call is protected by an
always-false check: while the actual code to print the message is
optimized out by the compiler, the pi_entry structure is still emitted.

Fix this by replacing "if (0) printk(...)" constructs by calls to the
no_printk() helper.

This reduces the size of an arm64 kernel with CONFIG_PRINTK_INDEX=y and
CONFIG_CEPH_FS=y by ca. 4 KiB.

Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
---
 include/linux/ceph/ceph_debug.h | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/include/linux/ceph/ceph_debug.h b/include/linux/ceph/ceph_debug.h
index 11a92a946016eab5..5f904591fa5f9e57 100644
--- a/include/linux/ceph/ceph_debug.h
+++ b/include/linux/ceph/ceph_debug.h
@@ -27,17 +27,13 @@
 		 ##__VA_ARGS__)
 # else
 /* faux printk call just to see any compiler warnings. */
-#  define dout(fmt, ...)	do {				\
-		if (0)						\
-			printk(KERN_DEBUG fmt, ##__VA_ARGS__);	\
-	} while (0)
-#  define doutc(client, fmt, ...)	do {			\
-		if (0)						\
-			printk(KERN_DEBUG "[%pU %llu] " fmt,	\
-			&client->fsid,				\
-			client->monc.auth->global_id,		\
-			##__VA_ARGS__);				\
-		} while (0)
+#  define dout(fmt, ...)					\
+		no_printk(KERN_DEBUG fmt, ##__VA_ARGS__)
+#  define doutc(client, fmt, ...)				\
+		no_printk(KERN_DEBUG "[%pU %llu] " fmt,		\
+			  &client->fsid,			\
+			  client->monc.auth->global_id,		\
+			  ##__VA_ARGS__)
 # endif
 
 #else
-- 
2.34.1