Commit 9fc4468d authored Oct 02, 2015 by Rasmus Villemoes Committed by Thomas Gleixner Oct 11, 2015

timers: Use __fls in apply_slack()



In apply_slack(), find_last_bit() is applied to a bitmask consisting
of precisely BITS_PER_LONG bits. Since mask is non-zero, we might as
well eliminate the function call and use __fls() directly. On x86_64,
this shaves 23 bytes of the only caller, mod_timer().

This also gets rid of Coverity CID 1192106, but that is a false
positive: Coverity is not aware that mask != 0 implies that
find_last_bit will not return BITS_PER_LONG.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1443771931-6284-1-git-send-email-linux@rasmusvillemoes.dk


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent cfed432d

kernel/time/timer.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -874,7 +874,7 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
		if (mask == 0)
		return expires;

		bit = find_last_bit(&mask, BITS_PER_LONG);
		bit = __fls(mask);

		mask = (1UL << bit) - 1;