Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | [PATCH] Futex update IV: use a waitqueue. | Date | Thu, 06 Jun 2002 17:15:37 +1000 |
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Name: Use a waitqueue, rather than a task ptr Author: Rusty Russell Status: Tested in 2.5.20 Depends: Futex/copy-from-user.patch.gz
D: This turns the simple task pointer into a waitqueue, which is D: needed for the poll() patch.
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal linux-2.5.20.18954/kernel/futex.c linux-2.5.20.18954.updated/kernel/futex.c --- linux-2.5.20.18954/kernel/futex.c Thu Jun 6 17:12:20 2002 +++ linux-2.5.20.18954.updated/kernel/futex.c Thu Jun 6 17:13:05 2002 @@ -49,7 +49,7 @@ the relevent ones (hashed queues may be shared) */ struct futex_q { struct list_head list; - struct task_struct *task; + wait_queue_head_t waiters; /* Page struct and offset within it. */ struct page *page; unsigned int offset; @@ -69,6 +69,11 @@ return &futex_queues[hash_long(h, FUTEX_HASHBITS)]; } +static inline void tell_waiter(struct futex_q *q) +{ + wake_up_all(&q->waiters); +} + static int futex_wake(struct list_head *head, struct page *page, unsigned int offset, @@ -83,7 +88,7 @@ if (this->page == page && this->offset == offset) { list_del_init(i); - wake_up_process(this->task); + tell_waiter(this); num_woken++; if (num_woken >= num) break; } @@ -94,11 +99,12 @@ /* Add at end to avoid starvation */ static inline void queue_me(struct list_head *head, + wait_queue_t *wait, struct futex_q *q, struct page *page, unsigned int offset) { - q->task = current; + add_wait_queue(&q->waiters, wait); q->page = page; q->offset = offset; @@ -150,10 +156,11 @@ { int curval; struct futex_q q; + DECLARE_WAITQUEUE(wait, current); int ret = 0; set_current_state(TASK_INTERRUPTIBLE); - queue_me(head, &q, page, offset); + queue_me(head, &wait, &q, page, offset); /* Page is pinned, but may no longer be in this address space. */ if (get_user(curval, uaddr) != 0) { -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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