Make use of restart_block when the lock operation has been interrupted.
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
kernel/futex.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 72 insertions(+), 10 deletions(-)
Index: linux-2.6.17-rc1-mm3/kernel/futex.c
===================================================================
--- linux-2.6.17-rc1-mm3.orig/kernel/futex.c
+++ linux-2.6.17-rc1-mm3/kernel/futex.c
@@ -1077,26 +1077,18 @@ static int futex_wait(u32 __user *uaddr,
* if there are waiters then it will block, it does PI, etc. (Due to
* races the kernel might see a 0 value of the futex too.)
*/
-static int futex_lock_pi(u32 __user *uaddr, int detect,
- unsigned long sec, long nsec, int trylock)
+static int do_futex_lock_pi(u32 __user *uaddr, int detect, int trylock,
+ struct hrtimer_sleeper *to)
{
struct task_struct *curr = current;
struct futex_hash_bucket *hb;
u32 uval, newval, curval;
struct futex_q q;
- struct hrtimer_sleeper timeout, *to = NULL;
int ret, attempt = 0;
if (refill_pi_state_cache())
return -ENOMEM;
- if (sec != MAX_SCHEDULE_TIMEOUT) {
- to = &timeout;
- hrtimer_init(&to->timer, CLOCK_REALTIME, HRTIMER_ABS);
- hrtimer_init_sleeper(to, current);
- to->timer.expires = ktime_set(sec, nsec);
- }
-
q.pi_state = NULL;
retry:
down_read(&curr->mm->mmap_sem);
@@ -1304,6 +1296,76 @@ static int futex_lock_pi(u32 __user *uad
}
/*
+ * Restart handler
+ */
+static long futex_lock_pi_restart(struct restart_block *restart)
+{
+ struct hrtimer_sleeper timeout, *to = NULL;
+ int ret;
+
+ restart->fn = do_no_restart_syscall;
+
+ if (restart->arg2 || restart->arg3) {
+ to = &timeout;
+ hrtimer_init(&to->timer, CLOCK_REALTIME, HRTIMER_ABS);
+ hrtimer_init_sleeper(to, current);
+ to->timer.expires.tv64 = ((u64)restart->arg1 << 32) |
+ (u64) restart->arg0;
+ }
+
+ pr_debug("lock_pi restart: %p, %d (%d)\n",
+ (u32 __user *)restart->arg0, current->pid);
+
+ ret = do_futex_lock_pi((u32 __user *)restart->arg0, restart->arg1,
+ 0, to);
+
+ if (ret != -EINTR)
+ return ret;
+
+ restart->fn = futex_lock_pi_restart;
+
+ /* The other values are filled in */
+ return -ERESTART_RESTARTBLOCK;
+}
+
+/*
+ * Called from the syscall entry below.
+ */
+static int futex_lock_pi(u32 __user *uaddr, int detect, unsigned long sec,
+ long nsec, int trylock)
+{
+ struct hrtimer_sleeper timeout, *to = NULL;
+ struct restart_block *restart;
+ int ret;
+
+ if (sec != MAX_SCHEDULE_TIMEOUT) {
+ to = &timeout;
+ hrtimer_init(&to->timer, CLOCK_REALTIME, HRTIMER_ABS);
+ hrtimer_init_sleeper(to, current);
+ to->timer.expires = ktime_set(sec, nsec);
+ }
+
+ ret = do_futex_lock_pi(uaddr, detect, trylock, to);
+
+ if (ret != -EINTR)
+ return ret;
+
+ pr_debug("lock_pi interrupted: %p, %d (%d)\n", uaddr, current->pid);
+
+ restart = ¤t_thread_info()->restart_block;
+ restart->fn = futex_lock_pi_restart;
+ restart->arg0 = (unsigned long) uaddr;
+ restart->arg1 = detect;
+ if (to) {
+ restart->arg2 = to->timer.expires.tv64 & 0xFFFFFFFF;
+ restart->arg3 = to->timer.expires.tv64 >> 32;
+ } else
+ restart->arg2 = restart->arg3 = 0;
+
+ return -ERESTART_RESTARTBLOCK;
+}
+
+/*
* Userspace attempted a TID -> 0 atomic transition, and failed.
* This is the in-kernel slowpath: we look up the PI state (if any),
* and do the rt-mutex unlock.
--
-
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