| Message ID | 1454029869-15585-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/include/linux/printk.h b/include/linux/printk.h index 4d5bf57..20370e66 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -104,13 +104,13 @@ struct va_format { /* * Dummy printk for disabled debugging statements to use whilst maintaining - * gcc's format and side-effect checking. + * gcc's format checking. */ -static inline __printf(1, 2) -int no_printk(const char *fmt, ...) -{ - return 0; -} +#define no_printk(fmt, ...) \ +do { \ + if (0) \ + printk(fmt, ##__VA_ARGS__); \ +} while (0) #ifdef CONFIG_EARLY_PRINTK extern asmlinkage __printf(1, 2)
This is a note to let you know that I have just added a patch titled printk: help pr_debug and pr_devel to optimize out arguments to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt14. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From e51935904962ff61aa95b6f61066ff4dda2ed6ad Mon Sep 17 00:00:00 2001 From: Aaron Conole <aconole@redhat.com> Date: Fri, 15 Jan 2016 16:59:12 -0800 Subject: printk: help pr_debug and pr_devel to optimize out arguments commit fe22cd9b7c980b8b948ec85f034a8668c57ec867 upstream. Currently, pr_debug and pr_devel will not elide function call arguments appearing in calls to the no_printk for these macros. This is because all side effects must be honored before proceeding to the 0-value assignment in no_printk. The behavior is contrary to documentation found in the CodingStyle and the header file where these functions are declared. This patch corrects that behavior by shunting out the call to no_printk completely. The format string is still checked by gcc for correctness, but no code seems to be emitted in common cases. [akpm@linux-foundation.org: remove braces, per Joe] Fixes: 5264f2f75d86 ("include/linux/printk.h: use and neaten no_printk") Signed-off-by: Aaron Conole <aconole@redhat.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: Joe Perches <joe@perches.com> Cc: Jason Baron <jbaron@akamai.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- include/linux/printk.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) -- 1.9.1