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>

1 files changed, 5 insertions, 4 deletions

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index 515148d4eeb1..3adfa42ca24c 100644
--- 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;