signal: sys_rt_sigtimedwait: simplify the timeout logic

No functional changes, cleanup compat_sys_rt_sigtimedwait() and
sys_rt_sigtimedwait().

Calculate the timeout before we take ->siglock, this simplifies and
lessens the code. Use timespec_valid() to check the timespec.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>

1 files changed, 18 insertions, 24 deletions

diff --git a/kernel/compat.c b/kernel/compat.c
index 38b1d2c1cbe8..06cbb0619531 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -893,7 +893,7 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
         int sig;
         struct timespec t;
         siginfo_t info;
-        long ret, timeout = 0;
+        long ret, timeout;
 
         if (sigsetsize != sizeof(sigset_t))
                 return -EINVAL;
@@ -904,36 +904,30 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
         sigdelsetmask(&s,sigmask(SIGKILL)|sigmask(SIGSTOP));
         signotset(&s);
 
+        timeout = MAX_SCHEDULE_TIMEOUT;
         if (uts) {
                 if (get_compat_timespec (&t, uts))
                         return -EFAULT;
-                if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0
-                                || t.tv_sec < 0)
+                if (!timespec_valid(&t))
                         return -EINVAL;
+                timeout = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
         }
 
         spin_lock_irq(&current->sighand->siglock);
         sig = dequeue_signal(current, &s, &info);
-        if (!sig) {
-                timeout = MAX_SCHEDULE_TIMEOUT;
-                if (uts)
-                        timeout = timespec_to_jiffies(&t)
-                                +(t.tv_sec || t.tv_nsec);
-                if (timeout) {
-                        current->real_blocked = current->blocked;
-                        sigandsets(&current->blocked, &current->blocked, &s);
-
-                        recalc_sigpending();
-                        spin_unlock_irq(&current->sighand->siglock);
-
-                        timeout = schedule_timeout_interruptible(timeout);
-
-                        spin_lock_irq(&current->sighand->siglock);
-                        sig = dequeue_signal(current, &s, &info);
-                        current->blocked = current->real_blocked;
-                        siginitset(&current->real_blocked, 0);
-                        recalc_sigpending();
-                }
+        if (!sig && timeout) {
+                current->real_blocked = current->blocked;
+                sigandsets(&current->blocked, &current->blocked, &s);
+                recalc_sigpending();
+                spin_unlock_irq(&current->sighand->siglock);
+
+                timeout = schedule_timeout_interruptible(timeout);
+
+                spin_lock_irq(&current->sighand->siglock);
+                sig = dequeue_signal(current, &s, &info);
+                current->blocked = current->real_blocked;
+                siginitset(&current->real_blocked, 0);
+                recalc_sigpending();
         }
         spin_unlock_irq(&current->sighand->siglock);
 
@@ -943,7 +937,7 @@ compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
                         if (copy_siginfo_to_user32(uinfo, &info))
                                 ret = -EFAULT;
                 }
-        }else {
+        } else {
                 ret = timeout?-EINTR:-EAGAIN;
         }
         return ret;