5.15-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 8522f6b760ca588928eede740d5d69dd1e936b49 ]
When printk-indexing is enabled, each printk() invocation emits a pi_entry structure, containing the format string and other information related to its location in the kernel sources. This is even true for no_printk(): while the actual code to print the message is optimized out by the compiler due to the always-false check, the pi_entry structure is still emitted.
As the main purpose of no_printk() is to provide a helper to maintain printf()-style format checking when debugging is disabled, this leads to the inclusion in the index of lots of printk formats that cannot be emitted by the current kernel.
Fix this by switching no_printk() from printk() to _printk().
This reduces the size of an arm64 defconfig kernel with CONFIG_PRINTK_INDEX=y by 576 KiB.
Fixes: 337015573718b161 ("printk: Userspace format indexing support") 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/56cf92edccffea970e1f40a075334dd6cf5bb2a4.170912747... Signed-off-by: Petr Mladek pmladek@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/printk.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/printk.h b/include/linux/printk.h index 9497f6b983399..c4fb84822111d 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -129,7 +129,7 @@ struct va_format { #define no_printk(fmt, ...) \ ({ \ if (0) \ - printk(fmt, ##__VA_ARGS__); \ + _printk(fmt, ##__VA_ARGS__); \ 0; \ })