From a7602681fc63f1a3ddd3da336296c9634c2ff974 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 7 Jun 2017 09:42:29 +0100 Subject: [PATCH] hrtimer: Move copyout of remaining time to do_nanosleep() The hrtimer nanosleep() implementation can be simplified by moving the copy out of the remaining time to do_nanosleep() which is shared between the real nanosleep function and the restart function. The pointer to the timespec64 which is updated is already stored in the restart block at the call site, so the seperate handling of nanosleep and restart function can be avoided. [ tglx: Added changelog ] Signed-off-by: Al Viro Signed-off-by: Thomas Gleixner Cc: John Stultz Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20170607084241.28657-4-viro@ZenIV.linux.org.uk --- kernel/time/hrtimer.c | 62 ++++++++++++++----------------------------- 1 file changed, 20 insertions(+), 42 deletions(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 4ae777f159de..baa7b846b6e3 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1441,6 +1441,7 @@ EXPORT_SYMBOL_GPL(hrtimer_init_sleeper); static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mode) { + struct timespec __user *rmtp; hrtimer_init_sleeper(t, current); do { @@ -1457,48 +1458,33 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod __set_current_state(TASK_RUNNING); - return t->task == NULL; -} - -static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp) -{ - struct timespec rmt; - ktime_t rem; - - rem = hrtimer_expires_remaining(timer); - if (rem <= 0) + if (!t->task) return 0; - rmt = ktime_to_timespec(rem); - if (copy_to_user(rmtp, &rmt, sizeof(*rmtp))) - return -EFAULT; - - return 1; + rmtp = current->restart_block.nanosleep.rmtp; + if (rmtp) { + struct timespec rmt; + ktime_t rem = hrtimer_expires_remaining(&t->timer); + if (rem <= 0) + return 0; + rmt = ktime_to_timespec(rem); + + if (copy_to_user(rmtp, &rmt, sizeof(*rmtp))) + return -EFAULT; + } + return -ERESTART_RESTARTBLOCK; } long __sched hrtimer_nanosleep_restart(struct restart_block *restart) { struct hrtimer_sleeper t; - struct timespec __user *rmtp; - int ret = 0; + int ret; hrtimer_init_on_stack(&t.timer, restart->nanosleep.clockid, HRTIMER_MODE_ABS); hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires); - if (do_nanosleep(&t, HRTIMER_MODE_ABS)) - goto out; - - rmtp = restart->nanosleep.rmtp; - if (rmtp) { - ret = update_rmtp(&t.timer, rmtp); - if (ret <= 0) - goto out; - } - - /* The other values in restart are already filled in */ - ret = -ERESTART_RESTARTBLOCK; -out: + ret = do_nanosleep(&t, HRTIMER_MODE_ABS); destroy_hrtimer_on_stack(&t.timer); return ret; } @@ -1506,8 +1492,7 @@ out: long hrtimer_nanosleep(struct timespec64 *rqtp, const enum hrtimer_mode mode, const clockid_t clockid) { - struct restart_block *restart = ¤t->restart_block; - struct timespec __user *rmtp; + struct restart_block *restart; struct hrtimer_sleeper t; int ret = 0; u64 slack; @@ -1518,7 +1503,8 @@ long hrtimer_nanosleep(struct timespec64 *rqtp, hrtimer_init_on_stack(&t.timer, clockid, mode); hrtimer_set_expires_range_ns(&t.timer, timespec64_to_ktime(*rqtp), slack); - if (do_nanosleep(&t, mode)) + ret = do_nanosleep(&t, mode); + if (ret != -ERESTART_RESTARTBLOCK) goto out; /* Absolute timers do not update the rmtp value and restart: */ @@ -1527,18 +1513,10 @@ long hrtimer_nanosleep(struct timespec64 *rqtp, goto out; } - rmtp = restart->nanosleep.rmtp; - if (rmtp) { - ret = update_rmtp(&t.timer, rmtp); - if (ret <= 0) - goto out; - } - + restart = ¤t->restart_block; restart->fn = hrtimer_nanosleep_restart; restart->nanosleep.clockid = t.timer.base->clockid; restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer); - - ret = -ERESTART_RESTARTBLOCK; out: destroy_hrtimer_on_stack(&t.timer); return ret; -- 2.20.1