[tip:sched/core] sched/cputime: Refactor the cputime_adjust() code

tip-bot for Gustavo A. R. Silva
2017-06-30T13:15:28Z

Commit-ID: 72298e5c92c50edd8cb7cfda4519483ce65fa166
Gitweb: http://git.kernel.org/tip/72298e5c92c50edd8cb7cfda4519483ce65fa166
Author: Gustavo A. R. Silva <garsilva@embeddedor.com>
AuthorDate: Thu, 29 Jun 2017 13:41:28 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 30 Jun 2017 09:37:59 +0200

sched/cputime: Refactor the cputime_adjust() code

Address a Coverity false positive, which is caused by overly
convoluted code:

Value assigned to variable 'utime' at line 619:utime = rtime;
is overwritten at line 642:utime = rtime - stime; before it
can be used. This makes such variable assignment useless.

Remove this variable assignment and refactor the code related.

Addresses-Coverity-ID: 1371643
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Cc: Frans Klaver <fransklaver@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/20170629184128.GA5271@embeddedgus
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/cputime.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index aea3135..67c70e2 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -615,19 +615,13 @@ static void cputime_adjust(struct task_cputime *curr,
* userspace. Once a task gets some ticks, the monotonicy code at
* 'update' will ensure things converge to the observed ratio.
*/
- if (stime == 0) {
- utime = rtime;
- goto update;
+ if (stime != 0) {
+ if (utime == 0)
+ stime = rtime;
+ else
+ stime = scale_stime(stime, rtime, stime + utime);
}

- if (utime == 0) {
- stime = rtime;
- goto update;
- }
-
- stime = scale_stime(stime, rtime, stime + utime);
-
-update:
/*
* Make sure stime doesn't go backwards; this preserves monotonicity
* for utime because rtime is monotonic.