[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>

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 5667fef89dd1fa98ca1180fe42e2e659d9505069..479b16b44f79f6b639683c724405f51b3ecc156f 100644 (file)
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1393,22 +1393,12 @@ 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.
         */
@@ -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;
+
 }