posix-cpu-timers: Avoid timespec conversion in do_cpu_nanosleep()

No point in converting the expiry time back and forth.

No point either to update the value in the caller supplied variable. mark
the rqtp argument const.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 515148d4eeb13c3c3ae603528410b077828e8444..3adfa42ca24ce5b5c13e7fba50a83c77ead2bedd 100644 (file)
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -1227,10 +1227,11 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
 }
 
 static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
-                           struct timespec64 *rqtp)
+                           const struct timespec64 *rqtp)
 {
-       struct k_itimer timer;
        struct itimerspec64 it;
+       struct k_itimer timer;
+       u64 expires;
        int error;
 
        /*
@@ -1279,7 +1280,7 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
                /*
                 * We were interrupted by a signal.
                 */
-               *rqtp = ns_to_timespec64(timer.it.cpu.expires);
+               expires = timer.it.cpu.expires;
                error = posix_cpu_timer_set(&timer, 0, &zero_it, &it);
                if (!error) {
                        /*
@@ -1312,7 +1313,7 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
                 * Report back to the user the time still remaining.
                 */
                restart = &current->restart_block;
-               restart->nanosleep.expires = timespec64_to_ns(rqtp);
+               restart->nanosleep.expires = expires;
                if (restart->nanosleep.type != TT_NONE) {
                        struct timespec ts;