posix-timers: Use get_timespec64() and put_timespec64()

Usage of these apis and their compat versions makes
the syscalls: clock_gettime, clock_settime, clock_getres
and their compat implementations simpler.

This is a preparatory patch to isolate data conversions to
struct timespec64 at userspace boundaries. This helps contain
the changes needed to transition to new y2038 safe types.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 45 insertions, 38 deletions

diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 65878221cbfb..06f34feb635e 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -51,40 +51,52 @@ SYS_NI(alarm);
 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
 		const struct timespec __user *, tp)
 {
-	struct timespec64 new_tp64;
-	struct timespec new_tp;
+	struct timespec64 new_tp;
 
 	if (which_clock != CLOCK_REALTIME)
 		return -EINVAL;
-	if (copy_from_user(&new_tp, tp, sizeof (*tp)))
+	if (get_timespec64(&new_tp, tp))
 		return -EFAULT;
 
-	new_tp64 = timespec_to_timespec64(new_tp);
-	return do_sys_settimeofday64(&new_tp64, NULL);
+	return do_sys_settimeofday64(&new_tp, NULL);
 }
 
-SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
-		struct timespec __user *,tp)
+int do_clock_gettime(clockid_t which_clock, struct timespec64 *tp)
 {
-	struct timespec64 kernel_tp64;
-	struct timespec kernel_tp;
-
 	switch (which_clock) {
-	case CLOCK_REALTIME: ktime_get_real_ts64(&kernel_tp64); break;
-	case CLOCK_MONOTONIC: ktime_get_ts64(&kernel_tp64); break;
-	case CLOCK_BOOTTIME: get_monotonic_boottime64(&kernel_tp64); break;
-	default: return -EINVAL;
+	case CLOCK_REALTIME:
+		ktime_get_real_ts64(tp);
+		break;
+	case CLOCK_MONOTONIC:
+		ktime_get_ts64(tp);
+		break;
+	case CLOCK_BOOTTIME:
+		get_monotonic_boottime64(tp);
+		break;
+	default:
+		return -EINVAL;
 	}
 
-	kernel_tp = timespec64_to_timespec(kernel_tp64);
-	if (copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
+	return 0;
+}
+SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
+		struct timespec __user *, tp)
+{
+	int ret;
+	struct timespec64 kernel_tp;
+
+	ret = do_clock_gettime(which_clock, &kernel_tp);
+	if (ret)
+		return ret;
+
+	if (put_timespec64(&kernel_tp, tp))
 		return -EFAULT;
 	return 0;
 }
 
 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct timespec __user *, tp)
 {
-	struct timespec rtn_tp = {
+	struct timespec64 rtn_tp = {
 		.tv_sec = 0,
 		.tv_nsec = hrtimer_resolution,
 	};
@@ -93,7 +105,7 @@ SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct timespec __us
 	case CLOCK_REALTIME:
 	case CLOCK_MONOTONIC:
 	case CLOCK_BOOTTIME:
-		if (copy_to_user(tp, &rtn_tp, sizeof(rtn_tp)))
+		if (put_timespec64(&rtn_tp, tp))
 			return -EFAULT;
 		return 0;
 	default:
@@ -142,41 +154,35 @@ COMPAT_SYS_NI(setitimer);
 COMPAT_SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
 		       struct compat_timespec __user *, tp)
 {
-	struct timespec64 new_tp64;
-	struct timespec new_tp;
+	struct timespec64 new_tp;
 
 	if (which_clock != CLOCK_REALTIME)
 		return -EINVAL;
-	if (compat_get_timespec(&new_tp, tp))
+	if (compat_get_timespec64(&new_tp, tp))
 		return -EFAULT;
 
-	new_tp64 = timespec_to_timespec64(new_tp);
-	return do_sys_settimeofday64(&new_tp64, NULL);
+	return do_sys_settimeofday64(&new_tp, NULL);
 }
 
-COMPAT_SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
-		       struct compat_timespec __user *,tp)
+COMPAT_SYSCALL_DEFINE2(clock_gettime, clockid_t, which_clock,
+		       struct compat_timespec __user *, tp)
 {
-	struct timespec64 kernel_tp64;
-	struct timespec kernel_tp;
+	int ret;
+	struct timespec64 kernel_tp;
 
-	switch (which_clock) {
-	case CLOCK_REALTIME: ktime_get_real_ts64(&kernel_tp64); break;
-	case CLOCK_MONOTONIC: ktime_get_ts64(&kernel_tp64); break;
-	case CLOCK_BOOTTIME: get_monotonic_boottime64(&kernel_tp64); break;
-	default: return -EINVAL;
-	}
+	ret = do_clock_gettime(which_clock, &kernel_tp);
+	if (ret)
+		return ret;
 
-	kernel_tp = timespec64_to_timespec(kernel_tp64);
-	if (compat_put_timespec(&kernel_tp, tp))
+	if (compat_put_timespec64(&kernel_tp, tp))
 		return -EFAULT;
 	return 0;
 }
 
-COMPAT_SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
+COMPAT_SYSCALL_DEFINE2(clock_getres, clockid_t, which_clock,
 		       struct compat_timespec __user *, tp)
 {
-	struct timespec rtn_tp = {
+	struct timespec64 rtn_tp = {
 		.tv_sec = 0,
 		.tv_nsec = hrtimer_resolution,
 	};
@@ -185,13 +191,14 @@ COMPAT_SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
 	case CLOCK_REALTIME:
 	case CLOCK_MONOTONIC:
 	case CLOCK_BOOTTIME:
-		if (compat_put_timespec(&rtn_tp, tp))
+		if (compat_put_timespec64(&rtn_tp, tp))
 			return -EFAULT;
 		return 0;
 	default:
 		return -EINVAL;
 	}
 }
+
 COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, which_clock, int, flags,
 		       struct compat_timespec __user *, rqtp,
 		       struct compat_timespec __user *, rmtp)