[tip:timers/core] timers: Use __fls in apply_slack()
From: tip-bot for Rasmus Villemoes
Date: Sun Oct 11 2015 - 16:16:09 EST
Commit-ID: 9fc4468d546b6eb55b0aa5b04b0c36238ebf57e7
Gitweb: http://git.kernel.org/tip/9fc4468d546b6eb55b0aa5b04b0c36238ebf57e7
Author: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 2 Oct 2015 09:45:30 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sun, 11 Oct 2015 22:13:46 +0200
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@xxxxxxxxxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1443771931-6284-1-git-send-email-linux@xxxxxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/time/timer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index d3f5e92..74591ba 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -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;
--
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