On Wed, Jun 07, 2017 at 09:42:31AM +0100, Al Viro wrote:
> From: Al Viro <[email protected]>
> 
> 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.

I found something like the below on top slightly easier to read. Ignore
if hated..

---
 include/linux/restart_block.h  | 10 +++++++++-
 kernel/time/alarmtimer.c       |  2 +-
 kernel/time/hrtimer.c          | 23 +++++++++++++++--------
 kernel/time/posix-cpu-timers.c |  2 +-
 kernel/time/posix-stubs.c      |  4 ++--
 kernel/time/posix-timers.c     |  4 ++--
 6 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h
index 4509944bd953..0834e4a8ce69 100644
--- a/include/linux/restart_block.h
+++ b/include/linux/restart_block.h
@@ -11,6 +11,14 @@ struct timespec;
 struct compat_timespec;
 struct pollfd;
 
+enum timespec_type {
+       tt_nothing = 0,
+       tt_native  = 1,
+#ifdef CONFIG_COMPAT
+       tt_compat  = 2,
+#endif
+};
+
 /*
  * System call restart block.
  */
@@ -29,7 +37,7 @@ struct restart_block {
                /* For nanosleep */
                struct {
                        clockid_t clockid;
-                       int kind;
+                       enum timespec_type type;
                        union {
                                struct timespec __user *rmtp;
 #ifdef CONFIG_COMPAT
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 80154e795535..734920be9d4b 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -711,7 +711,7 @@ static int alarmtimer_do_nsleep(struct alarm *alarm, 
ktime_t absexp,
        if (freezing(current))
                alarmtimer_freezerset(absexp, type);
        restart = &current->restart_block;
-       if (restart->nanosleep.kind) {
+       if (restart->nanosleep.type) {
                struct timespec rmt;
                ktime_t rem;
 
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 5dd4b3a34495..e1e06a8b6c43 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1442,15 +1442,22 @@ EXPORT_SYMBOL_GPL(hrtimer_init_sleeper);
 
 int nanosleep_copyout(struct restart_block *restart, struct timespec *ts)
 {
-       BUG_ON(!restart->nanosleep.kind);
+       switch(restart->nanosleep.type) {
 #ifdef CONFIG_COMPAT
-       if (restart->nanosleep.kind == 2) {
+       case tt_compat:
                if (compat_put_timespec(ts, restart->nanosleep.compat_rmtp))
                        return -EFAULT;
-       } else
+               break;
 #endif
-       if (copy_to_user(restart->nanosleep.rmtp, ts, sizeof(struct timespec)))
-               return -EFAULT;
+       case tt_native:
+               if (copy_to_user(restart->nanosleep.rmtp, ts, sizeof(struct 
timespec)))
+                       return -EFAULT;
+               break;
+
+       case tt_nothing:
+               BUG();
+       }
+
        return -ERESTART_RESTARTBLOCK;
 }
 
@@ -1477,7 +1484,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper 
*t, enum hrtimer_mode mod
                return 0;
 
        restart = &current->restart_block;
-       if (restart->nanosleep.kind) {
+       if (restart->nanosleep.type) {
                struct timespec rmt;
                ktime_t rem = hrtimer_expires_remaining(&t->timer);
                if (rem <= 0)
@@ -1549,7 +1556,7 @@ SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
        if (!timespec64_valid(&tu64))
                return -EINVAL;
 
-       current->restart_block.nanosleep.kind = rmtp ? 1 : 0;
+       current->restart_block.nanosleep.type = rmtp ? tt_native : tt_nothing;
        current->restart_block.nanosleep.rmtp = rmtp;
        return hrtimer_nanosleep(&tu64, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
 }
@@ -1569,7 +1576,7 @@ COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec 
__user *, rqtp,
        if (!timespec64_valid(&tu64))
                return -EINVAL;
 
-       current->restart_block.nanosleep.kind = rmtp ? 2 : 0;
+       current->restart_block.nanosleep.type = rmtp ? tt_compat : tt_nothing;
        current->restart_block.nanosleep.compat_rmtp = rmtp;
        return hrtimer_nanosleep(&tu64, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
 }
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index f6c5f77b944d..929499e6b4ac 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -1313,7 +1313,7 @@ static int do_cpu_nanosleep(const clockid_t which_clock, 
int flags,
                 */
                restart = &current->restart_block;
                restart->nanosleep.expires = timespec64_to_ns(rqtp);
-               if (restart->nanosleep.kind) {
+               if (restart->nanosleep.type) {
                        struct timespec ts;
                        ts = timespec64_to_timespec(it.it_value);
                        error = nanosleep_copyout(restart, &ts);
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index c0c18701a4da..4b54dcf8d517 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -125,7 +125,7 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, 
which_clock, int, flags,
                        return -EINVAL;
                if (flags & TIMER_ABSTIME)
                        rmtp = NULL;
-               current->restart_block.nanosleep.kind = rmtp ? 1 : 0;
+               current->restart_block.nanosleep.type = rmtp ? tt_native : 
tt_nothing;
                current->restart_block.nanosleep.rmtp = rmtp;
                return hrtimer_nanosleep(&t64, flags & TIMER_ABSTIME ?
                                         HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
@@ -206,7 +206,7 @@ COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, 
which_clock, int, flags,
                        return -EINVAL;
                if (flags & TIMER_ABSTIME)
                        rmtp = NULL;
-               current->restart_block.nanosleep.kind = rmtp ? 2 : 0;
+               current->restart_block.nanosleep.type = rmtp ? tt_compat : 
tt_nothing;
                current->restart_block.nanosleep.compat_rmtp = rmtp;
                return hrtimer_nanosleep(&t64, flags & TIMER_ABSTIME ?
                                         HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 014e6ff8982e..3c85d6762690 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1228,7 +1228,7 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, 
which_clock, int, flags,
                return -EINVAL;
        if (flags & TIMER_ABSTIME)
                rmtp = NULL;
-       current->restart_block.nanosleep.kind = rmtp ? 1 : 0;
+       current->restart_block.nanosleep.type = rmtp ? tt_native : tt_nothing;
        current->restart_block.nanosleep.rmtp = rmtp;
 
        return kc->nsleep(which_clock, flags, &t64);
@@ -1256,7 +1256,7 @@ COMPAT_SYSCALL_DEFINE4(clock_nanosleep, clockid_t, 
which_clock, int, flags,
                return -EINVAL;
        if (flags & TIMER_ABSTIME)
                rmtp = NULL;
-       current->restart_block.nanosleep.kind = rmtp ? 2 : 0;
+       current->restart_block.nanosleep.type = rmtp ? tt_compat : tt_nothing;
        current->restart_block.nanosleep.compat_rmtp = rmtp;
 
        return kc->nsleep(which_clock, flags, &t64);

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