[PATCH] posix-timers: Fix the flags handling in posix_cpu_nsleep()

When a posix_cpu_nsleep() sleep is interrupted by a signal more than twice, it
incorrectly reports the sleep time remaining to the user.  Because
posix_cpu_nsleep() doesn't report back to the user when it's called from
restart function due to the wrong flags handling.

This patch, which applies after previous one, moves the nanosleep() function
from posix_cpu_nsleep() to do_cpu_nanosleep() and cleans up the flags handling
appropriately.

Signed-off-by: Toyo Abe <toyoa@mvista.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 58 insertions, 26 deletions

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 5667fef89dd1..479b16b44f79 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1393,23 +1393,13 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
         }
 }
 
-int posix_cpu_nsleep(const clockid_t which_clock, int flags,
-                     struct timespec *rqtp, struct timespec __user *rmtp)
+static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
+                            struct timespec *rqtp, struct itimerspec *it)
 {
-        struct restart_block *restart_block =
-            &current_thread_info()->restart_block;
         struct k_itimer timer;
         int error;
 
         /*
-         * Diagnose required errors first.
-         */
-        if (CPUCLOCK_PERTHREAD(which_clock) &&
-            (CPUCLOCK_PID(which_clock) == 0 ||
-             CPUCLOCK_PID(which_clock) == current->pid))
-                return -EINVAL;
-
-        /*
          * Set up a temporary timer and then wait for it to go off.
          */
         memset(&timer, 0, sizeof timer);
@@ -1420,11 +1410,12 @@ int posix_cpu_nsleep(const clockid_t which_clock, int flags,
         timer.it_process = current;
         if (!error) {
                 static struct itimerspec zero_it;
-                struct itimerspec it = { .it_value = *rqtp,
-                                         .it_interval = {} };
+
+                memset(it, 0, sizeof *it);
+                it->it_value = *rqtp;
 
                 spin_lock_irq(&timer.it_lock);
-                error = posix_cpu_timer_set(&timer, flags, &it, NULL);
+                error = posix_cpu_timer_set(&timer, flags, it, NULL);
                 if (error) {
                         spin_unlock_irq(&timer.it_lock);
                         return error;
@@ -1452,33 +1443,56 @@ int posix_cpu_nsleep(const clockid_t which_clock, int flags,
                  * We were interrupted by a signal.
                  */
                 sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
-                posix_cpu_timer_set(&timer, 0, &zero_it, &it);
+                posix_cpu_timer_set(&timer, 0, &zero_it, it);
                 spin_unlock_irq(&timer.it_lock);
 
-                if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
+                if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
                         /*
                          * It actually did fire already.
                          */
                         return 0;
                 }
 
+                error = -ERESTART_RESTARTBLOCK;
+        }
+
+        return error;
+}
+
+int posix_cpu_nsleep(const clockid_t which_clock, int flags,
+                     struct timespec *rqtp, struct timespec __user *rmtp)
+{
+        struct restart_block *restart_block =
+            &current_thread_info()->restart_block;
+        struct itimerspec it;
+        int error;
+
+        /*
+         * Diagnose required errors first.
+         */
+        if (CPUCLOCK_PERTHREAD(which_clock) &&
+            (CPUCLOCK_PID(which_clock) == 0 ||
+             CPUCLOCK_PID(which_clock) == current->pid))
+                return -EINVAL;
+
+        error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
+
+        if (error == -ERESTART_RESTARTBLOCK) {
+
+                if (flags & TIMER_ABSTIME)
+                        return -ERESTARTNOHAND;
                 /*
-                 * Report back to the user the time still remaining.
-                 */
-                if (rmtp != NULL && !(flags & TIMER_ABSTIME) &&
-                    copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
+                 * Report back to the user the time still remaining.
+                 */
+                if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
                         return -EFAULT;
 
                 restart_block->fn = posix_cpu_nsleep_restart;
-                /* Caller already set restart_block->arg1 */
                 restart_block->arg0 = which_clock;
                 restart_block->arg1 = (unsigned long) rmtp;
                 restart_block->arg2 = rqtp->tv_sec;
                 restart_block->arg3 = rqtp->tv_nsec;
-
-                error = -ERESTART_RESTARTBLOCK;
         }
-
         return error;
 }
 
@@ -1487,13 +1501,31 @@ long posix_cpu_nsleep_restart(struct restart_block *restart_block)
         clockid_t which_clock = restart_block->arg0;
         struct timespec __user *rmtp;
         struct timespec t;
+        struct itimerspec it;
+        int error;
 
         rmtp = (struct timespec __user *) restart_block->arg1;
         t.tv_sec = restart_block->arg2;
         t.tv_nsec = restart_block->arg3;
 
         restart_block->fn = do_no_restart_syscall;
-        return posix_cpu_nsleep(which_clock, TIMER_ABSTIME, &t, rmtp);
+        error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
+
+        if (error == -ERESTART_RESTARTBLOCK) {
+                /*
+                 * Report back to the user the time still remaining.
+                 */
+                if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
+                        return -EFAULT;
+
+                restart_block->fn = posix_cpu_nsleep_restart;
+                restart_block->arg0 = which_clock;
+                restart_block->arg1 = (unsigned long) rmtp;
+                restart_block->arg2 = t.tv_sec;
+                restart_block->arg3 = t.tv_nsec;
+        }
+        return error;
+
 }