On Mon, 19 May 2003, Christoph Hellwig wrote:
> > +static inline
> > +struct page *__pin_page_atomic (struct page *page)
agreed, this is ugly, new patch attached.
Ingo
--- linux/kernel/futex.c.orig
+++ linux/kernel/futex.c
@@ -93,19 +93,17 @@ static inline struct list_head *hash_fut
FUTEX_HASHBITS)];
}
-/* Waiter either waiting in FUTEX_WAIT or poll(), or expecting signal */
-static inline void tell_waiter(struct futex_q *q)
-{
- wake_up_all(&q->waiters);
- if (q->filp)
- send_sigio(&q->filp->f_owner, q->fd, POLL_IN);
-}
-
/*
* Get kernel address of the user page and pin it.
*
* Must be called with (and returns with) all futex-MM locks held.
*/
+static inline struct page *__pin_page_atomic (struct page *page)
+{
+ if (!PageReserved(page))
+ get_page(page);
+ return page;
+}
static struct page *__pin_page(unsigned long addr)
{
struct mm_struct *mm = current->mm;
@@ -116,11 +115,8 @@ static struct page *__pin_page(unsigned
* Do a quick atomic lookup first - this is the fastpath.
*/
page = follow_page(mm, addr, 0);
- if (likely(page != NULL)) {
- if (!PageReserved(page))
- get_page(page);
- return page;
- }
+ if (likely(page != NULL))
+ return __pin_page_atomic(page);
/*
* No luck - need to fault in the page:
@@ -181,7 +177,9 @@ static int futex_wake(unsigned long uadd
if (this->page == page && this->offset == offset) {
list_del_init(i);
__detach_vcache(&this->vcache);
- tell_waiter(this);
+ wake_up_all(&this->waiters);
+ if (this->filp)
+ send_sigio(&this->filp->f_owner, this->fd, POLL_IN);
ret++;
if (ret >= num)
break;
@@ -208,7 +206,9 @@ static void futex_vcache_callback(vcache
spin_lock(&futex_lock);
if (!list_empty(&q->list)) {
+ unpin_page(q->page);
q->page = new_page;
+ __pin_page_atomic(new_page);
list_del(&q->list);
list_add_tail(&q->list, head);
}
@@ -273,14 +273,17 @@ static int futex_wait(unsigned long uadd
}
__queue_me(&q, page, uaddr, offset, -1, NULL);
- unlock_futex_mm();
-
- /* Page is pinned, but may no longer be in this address space. */
+ /*
+ * Page is pinned, but may no longer be in this address space.
+ * It cannot schedule, so we access it with the spinlock held.
+ */
if (get_user(curval, (int *)uaddr) != 0) {
+ unlock_futex_mm();
ret = -EFAULT;
goto out;
}
if (curval != val) {
+ unlock_futex_mm();
ret = -EWOULDBLOCK;
goto out;
}
@@ -293,8 +296,10 @@ static int futex_wait(unsigned long uadd
*/
add_wait_queue(&q.waiters, &wait);
set_current_state(TASK_INTERRUPTIBLE);
- if (!list_empty(&q.list))
+ if (!list_empty(&q.list)) {
+ unlock_futex_mm();
time = schedule_timeout(time);
+ }
set_current_state(TASK_RUNNING);
/*
* NOTE: we don't remove ourselves from the waitqueue because
@@ -310,7 +315,7 @@ out:
/* Were we woken up anyway? */
if (!unqueue_me(&q))
ret = 0;
- unpin_page(page);
+ unpin_page(q.page);
return ret;
}
-
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This archive was generated by hypermail 2b29 : Fri May 23 2003 - 22:00:33 EST