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, 14 insertions, 6 deletions

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index ec6258c9cde5..1563ca22cf1f 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -12,6 +12,7 @@
 #include <trace/events/timer.h>
 #include <linux/tick.h>
 #include <linux/workqueue.h>
+#include <linux/compat.h>
 
 #include "posix-timers.h"
 
@@ -1243,10 +1244,9 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
 	timer.it_process = current;
 	if (!error) {
 		static struct itimerspec64 zero_it;
-		struct restart_block *restart = &current->restart_block;
-		struct timespec __user *rmtp;
+		struct restart_block *restart;
 
-		memset(&it, 0, sizeof it);
+		memset(&it, 0, sizeof(it));
 		it.it_value = *rqtp;
 
 		spin_lock_irq(&timer.it_lock);
@@ -1311,12 +1311,20 @@ static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
 		/*
 		 * Report back to the user the time still remaining.
 		 */
-		rmtp = restart->nanosleep.rmtp;
-		if (rmtp) {
+		restart = &current->restart_block;
+		if (restart->nanosleep.type != TT_NONE) {
 			struct timespec ts;
 
 			ts = timespec64_to_timespec(it.it_value);
-			if (copy_to_user(rmtp, &ts, sizeof(*rmtp)))
+#ifdef CONFIG_COMPAT
+			if (restart->nanosleep.type == TT_COMPAT) {
+				if (compat_put_timespec(&ts,
+						restart->nanosleep.compat_rmtp))
+					return -EFAULT;
+			} else
+#endif
+			if (copy_to_user(restart->nanosleep.rmtp, &ts,
+					sizeof(ts)))
 				return -EFAULT;
 		}
 		restart->nanosleep.expires = timespec64_to_ns(rqtp);