6.6-stable review patch. If anyone has any objections, please let me know.
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From: Geert Uytterhoeven geert+renesas@glider.be
[ 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: ad7d61f159db7397 ("printk: index: Add indexing support to dev_printk") Signed-off-by: Geert Uytterhoeven geert+renesas@glider.be Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Reviewed-by: Xiubo Li xiubli@redhat.com Reviewed-by: Chris Down chris@chrisdown.name Reviewed-by: Petr Mladek pmladek@suse.com Link: https://lore.kernel.org/r/8583d54f1687c801c6cda8edddf2cf0344c6e883.170912747... Signed-off-by: Petr Mladek pmladek@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/dev_printk.h | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-)
diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h index 6bfe70decc9fb..ae80a303c216b 100644 --- a/include/linux/dev_printk.h +++ b/include/linux/dev_printk.h @@ -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
/*