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tick-sched: avoid a maybe-uninitialized warning

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The use of bitfields seems to confuse gcc, leading to a false-positive
warning in all compiler versions:

kernel/time/tick-sched.c: In function 'tick_nohz_idle_exit':
kernel/time/tick-sched.c:538:2: error: 'now' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This introduces a temporary variable to track the flags so gcc
doesn't have to evaluate twice, eliminating the code path that
leads to the warning.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85301
Fixes: 1cae544d42d2 ("nohz: Gather tick_sched booleans under a common flag field")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Arnd Bergmann 2018-04-09 14:23:33 +02:00 committed by Rafael J. Wysocki
parent 792ccb457a
commit bbe9a70a47
1 changed files with 6 additions and 3 deletions
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9
kernel/time/tick-sched.c
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@ -1134,6 +1134,7 @@ void tick_nohz_idle_restart_tick(void)
void tick_nohz_idle_exit(void)
{
struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
bool idle_active, tick_stopped;
ktime_t now;
local_irq_disable();
@ -1142,14 +1143,16 @@ void tick_nohz_idle_exit(void)
WARN_ON_ONCE(ts->timer_expires_base);
ts->inidle = 0;
idle_active = ts->idle_active;
tick_stopped = ts->tick_stopped;
if (ts->idle_active || ts->tick_stopped)
if (idle_active || tick_stopped)
now = ktime_get();
if (ts->idle_active)
if (idle_active)
tick_nohz_stop_idle(ts, now);
if (ts->tick_stopped)
if (tick_stopped)
__tick_nohz_idle_restart_tick(ts, now);
local_irq_enable();