Commit 99757b87 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Ma Wupeng
Browse files

dev_printk: Add and use dev_no_printk() 

stable inclusion
from stable-v6.6.33
commit fc49f4d1a15f88cdb1b90fba17cb8e11e7a9f167
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAD6H2

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fc49f4d1a15f88cdb1b90fba17cb8e11e7a9f167



--------------------------------

[ Upstream commit c26ec799042a3888935d59b599f33e41efedf5f8 ]

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

Avoid emitting pi_entry structures for unavailable dev_printk() kernel
messages by:
  1. Introducing a dev_no_printk() helper, mimicked after the existing
     no_printk() helper, which calls _dev_printk() instead of
     dev_printk(),
  2. Replacing all "if (0) dev_printk(...)" constructs by calls to the
     new helper.

This reduces the size of an arm64 defconfig kernel with
CONFIG_PRINTK_INDEX=y by 957 KiB.

Fixes: ad7d61f1 ("printk: index: Add indexing support to dev_printk")
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: default avatarXiubo Li <xiubli@redhat.com>
Reviewed-by: default avatarChris Down <chris@chrisdown.name>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/8583d54f1687c801c6cda8edddf2cf0344c6e883.1709127473.git.geert+renesas@glider.be


Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarWang Hai <wanghai38@huawei.com>
parent f916ce00

include/linux/dev_printk.h

+13 −12
Original line number Diff line number Diff line
@@ -129,6 +129,16 @@ void _dev_info(const struct device *dev, const char *fmt, ...) 
		_dev_printk(level, dev, fmt, ##__VA_ARGS__);		\

	})



/*

 * Dummy dev_printk for disabled debugging statements to use whilst maintaining

 * gcc's format checking.

 */

#define dev_no_printk(level, dev, fmt, ...)				\

	({								\

		if (0)							\

			_dev_printk(level, dev, fmt, ##__VA_ARGS__);	\

	})



/*

 * #defines for all the dev_<level> macros to prefix with whatever

 * possible use of #define dev_fmt(fmt) ...
@@ -158,10 +168,7 @@ void _dev_info(const struct device *dev, const char *fmt, ...) 
	dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__)

#else

#define dev_dbg(dev, fmt, ...)						\

({									\

	if (0)								\

		dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \

})

	dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__)

#endif



#ifdef CONFIG_PRINTK
@@ -247,20 +254,14 @@ do { \ 
} while (0)

#else

#define dev_dbg_ratelimited(dev, fmt, ...)				\

do {									\

	if (0)								\

		dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \

} while (0)

	dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__)

#endif



#ifdef VERBOSE_DEBUG

#define dev_vdbg	dev_dbg

#else

#define dev_vdbg(dev, fmt, ...)						\

({									\

	if (0)								\

		dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \

})

	dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__)

#endif



/*