time/posix-timers: Move the compat copyouts to the nanosleep implementations

Turn restart_block.nanosleep.{rmtp,compat_rmtp} into a tagged union (kind =
1 -> native, kind = 2 -> compat, kind = 0 -> nothing) and make the places
doing actual copyout handle compat as well as native (that will become a
helper in the next commit).  Result: compat wrappers, messing with
reassignments, etc. are gone.

[ tglx: Folded in a variant of Peter Zijlstras enum patch ]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170607084241.28657-6-viro@ZenIV.linux.org.uk

1 files changed, 42 insertions, 13 deletions

diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 156a5e6f3bd2..749b76f2d757 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -17,6 +17,7 @@
 #include <linux/ktime.h>
 #include <linux/timekeeping.h>
 #include <linux/posix-timers.h>
+#include <linux/compat.h>
 
 asmlinkage long sys_ni_posix_timers(void)
 {
@@ -110,25 +111,53 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
 	case CLOCK_REALTIME:
 	case CLOCK_MONOTONIC:
 	case CLOCK_BOOTTIME:
-		if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
-			return -EFAULT;
-		t64 = timespec_to_timespec64(t);
-		if (!timespec64_valid(&t64))
-			return -EINVAL;
-		if (flags & TIMER_ABSTIME)
-			rmtp = NULL;
-		current->restart_block.nanosleep.rmtp = rmtp;
-		return hrtimer_nanosleep(&t64, flags & TIMER_ABSTIME ?
-					 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
-					 which_clock);
+		break;
 	default:
 		return -EINVAL;
 	}
+
+	if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
+		return -EFAULT;
+	t64 = timespec_to_timespec64(t);
+	if (!timespec64_valid(&t64))
+		return -EINVAL;
+	if (flags & TIMER_ABSTIME)
+		rmtp = NULL;
+	current->restart_block.nanosleep.type = rmtp ? TT_NATIVE : TT_NONE;
+	current->restart_block.nanosleep.rmtp = rmtp;
+	return hrtimer_nanosleep(&t64, flags & TIMER_ABSTIME ?
+				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+				 which_clock);
 }
 
 #ifdef CONFIG_COMPAT
-long clock_nanosleep_restart(struct restart_block *restart_block)
+COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, which_clock, int, flags,
+		       struct compat_timespec __user *, rqtp,
+		       struct compat_timespec __user *, rmtp)
 {
-	return hrtimer_nanosleep_restart(restart_block);
+	struct timespec64 t64;
+	struct timespec t;
+
+	switch (which_clock) {
+	case CLOCK_REALTIME:
+	case CLOCK_MONOTONIC:
+	case CLOCK_BOOTTIME:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (compat_get_timespec(&t, rqtp))
+		return -EFAULT;
+	t64 = timespec_to_timespec64(t);
+	if (!timespec64_valid(&t64))
+		return -EINVAL;
+	if (flags & TIMER_ABSTIME)
+		rmtp = NULL;
+	current->restart_block.nanosleep.type = rmtp ? TT_COMPAT : TT_NONE;
+	current->restart_block.nanosleep.compat_rmtp = rmtp;
+	return hrtimer_nanosleep(&t64, flags & TIMER_ABSTIME ?
+				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+				 which_clock);
 }
 #endif