Name: Allow Futex Rehashing In Interrupt
Author: Rusty Russell
Status: Tested on 2.6.0-test4-bk2
Depends: 
Depends: Misc/qemu-page-offset.patch.gz

D: This patch simply uses spin_lock_irq() instead of spin_lock for the
D: futex lock, in preparation for the futex_rehash patch which needs to
D: operate on the futex hash table in IRQ context.

diff -urpN --exclude TAGS -X /home/rusty/devel/kernel/kernel-patches/current-dontdiff --minimal .5392-linux-2.6.0-test4-bk2/kernel/futex.c .5392-linux-2.6.0-test4-bk2.updated/kernel/futex.c
--- .5392-linux-2.6.0-test4-bk2/kernel/futex.c	2003-08-28 17:51:06.000000000 +1000
+++ .5392-linux-2.6.0-test4-bk2.updated/kernel/futex.c	2003-08-28 17:51:37.000000000 +1000
@@ -74,12 +74,12 @@ static inline void lock_futex_mm(void)
 {
 	spin_lock(&current->mm->page_table_lock);
 	spin_lock(&vcache_lock);
-	spin_lock(&futex_lock);
+	spin_lock_irq(&futex_lock);
 }
 
 static inline void unlock_futex_mm(void)
 {
-	spin_unlock(&futex_lock);
+	spin_unlock_irq(&futex_lock);
 	spin_unlock(&vcache_lock);
 	spin_unlock(&current->mm->page_table_lock);
 }
@@ -196,7 +196,7 @@ static void futex_vcache_callback(vcache
 	struct futex_q *q = container_of(vcache, struct futex_q, vcache);
 	struct list_head *head = hash_futex(new_page, q->offset);
 
-	spin_lock(&futex_lock);
+	spin_lock_irq(&futex_lock);
 
 	if (!list_empty(&q->list)) {
 		put_page(q->page);
@@ -206,7 +206,7 @@ static void futex_vcache_callback(vcache
 		list_add_tail(&q->list, head);
 	}
 
-	spin_unlock(&futex_lock);
+	spin_unlock_irq(&futex_lock);
 }
 
 /*
@@ -293,13 +293,13 @@ static inline int unqueue_me(struct fute
 	int ret = 0;
 
 	spin_lock(&vcache_lock);
-	spin_lock(&futex_lock);
+	spin_lock_irq(&futex_lock);
 	if (!list_empty(&q->list)) {
 		list_del(&q->list);
 		__detach_vcache(&q->vcache);
 		ret = 1;
 	}
-	spin_unlock(&futex_lock);
+	spin_unlock_irq(&futex_lock);
 	spin_unlock(&vcache_lock);
 	return ret;
 }
@@ -391,10 +391,10 @@ static unsigned int futex_poll(struct fi
 	int ret = 0;
 
 	poll_wait(filp, &q->waiters, wait);
-	spin_lock(&futex_lock);
+	spin_lock_irq(&futex_lock);
 	if (list_empty(&q->list))
 		ret = POLLIN | POLLRDNORM;
-	spin_unlock(&futex_lock);
+	spin_unlock_irq(&futex_lock);
 
 	return ret;
 }