Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=72c1bbf308c75a136803d2d76d0e18258be14c7a
Commit: 72c1bbf308c75a136803d2d76d0e18258be14c7a
Parent: 9adef58b1d4fbb58d7daed931b6790c5a3b7543a
Author: Nick Piggin <[EMAIL PROTECTED]>
AuthorDate: Tue May 8 00:26:43 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue May 8 11:15:03 2007 -0700
futex: restartable futex_wait
LTP test sigaction_16_24 fails, because it expects sem_wait to be restarted
if SA_RESTART is set. sem_wait is implemented with futex_wait, that
currently doesn't support being restarted. Ulrich confirms that the call
should be restartable.
Implement a restart_block method to handle the relative timeout, and allow
restarts.
Signed-off-by: Nick Piggin <[EMAIL PROTECTED]>
Cc: Ulrich Drepper <[EMAIL PROTECTED]>
Cc: Rusty Russell <[EMAIL PROTECTED]>
Cc: Roland McGrath <[EMAIL PROTECTED]>
Cc: Oleg Nesterov <[EMAIL PROTECTED]>
Acked-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
kernel/futex.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 51 insertions(+), 5 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index 7ae2f50..600bc9d 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -980,12 +980,15 @@ static void unqueue_me_pi(struct futex_q *q, struct
futex_hash_bucket *hb)
drop_futex_key_refs(&q->key);
}
-static int futex_wait(u32 __user *uaddr, u32 val, unsigned long time)
+static long futex_wait_restart(struct restart_block *restart);
+static int futex_wait_abstime(u32 __user *uaddr, u32 val,
+ int timed, unsigned long abs_time)
{
struct task_struct *curr = current;
DECLARE_WAITQUEUE(wait, curr);
struct futex_hash_bucket *hb;
struct futex_q q;
+ unsigned long time_left = 0;
u32 uval;
int ret;
@@ -1065,8 +1068,21 @@ static int futex_wait(u32 __user *uaddr, u32 val,
unsigned long time)
* !list_empty() is safe here without any lock.
* q.lock_ptr != 0 is not safe, because of ordering against wakeup.
*/
- if (likely(!list_empty(&q.list)))
- time = schedule_timeout(time);
+ time_left = 0;
+ if (likely(!list_empty(&q.list))) {
+ unsigned long rel_time;
+
+ if (timed) {
+ unsigned long now = jiffies;
+ if (time_after(now, abs_time))
+ rel_time = 0;
+ else
+ rel_time = abs_time - now;
+ } else
+ rel_time = MAX_SCHEDULE_TIMEOUT;
+
+ time_left = schedule_timeout(rel_time);
+ }
__set_current_state(TASK_RUNNING);
/*
@@ -1077,13 +1093,25 @@ static int futex_wait(u32 __user *uaddr, u32 val,
unsigned long time)
/* If we were woken (and unqueued), we succeeded, whatever. */
if (!unqueue_me(&q))
return 0;
- if (time == 0)
+ if (time_left == 0)
return -ETIMEDOUT;
+
/*
* We expect signal_pending(current), but another thread may
* have handled it for us already.
*/
- return -EINTR;
+ if (time_left == MAX_SCHEDULE_TIMEOUT)
+ return -ERESTARTSYS;
+ else {
+ struct restart_block *restart;
+ restart = ¤t_thread_info()->restart_block;
+ restart->fn = futex_wait_restart;
+ restart->arg0 = (unsigned long)uaddr;
+ restart->arg1 = (unsigned long)val;
+ restart->arg2 = (unsigned long)timed;
+ restart->arg3 = abs_time;
+ return -ERESTART_RESTARTBLOCK;
+ }
out_unlock_release_sem:
queue_unlock(&q, hb);
@@ -1093,6 +1121,24 @@ static int futex_wait(u32 __user *uaddr, u32 val,
unsigned long time)
return ret;
}
+static int futex_wait(u32 __user *uaddr, u32 val, unsigned long rel_time)
+{
+ int timed = (rel_time != MAX_SCHEDULE_TIMEOUT);
+ return futex_wait_abstime(uaddr, val, timed, jiffies+rel_time);
+}
+
+static long futex_wait_restart(struct restart_block *restart)
+{
+ u32 __user *uaddr = (u32 __user *)restart->arg0;
+ u32 val = (u32)restart->arg1;
+ int timed = (int)restart->arg2;
+ unsigned long abs_time = restart->arg3;
+
+ restart->fn = do_no_restart_syscall;
+ return (long)futex_wait_abstime(uaddr, val, timed, abs_time);
+}
+
+
/*
* Userspace tried a 0 -> TID atomic transition of the futex value
* and failed. The kernel side here does the whole locking operation:
-
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