[PATCH] uml: lock the irqs_to_free list
Fix (i.e. add some) the locking around the irqs_to_free list.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c
index 4e7e3cf..bce9b3427 100644
--- a/arch/um/drivers/chan_kern.c
+++ b/arch/um/drivers/chan_kern.c
@@ -222,15 +222,28 @@
}
}
+/* Items are added in IRQ context, when free_irq can't be called, and
+ * removed in process context, when it can.
+ * This handles interrupt sources which disappear, and which need to
+ * be permanently disabled. This is discovered in IRQ context, but
+ * the freeing of the IRQ must be done later.
+ */
+static DEFINE_SPINLOCK(irqs_to_free_lock);
static LIST_HEAD(irqs_to_free);
void free_irqs(void)
{
struct chan *chan;
+ LIST_HEAD(list);
+ struct list_head *ele;
- while(!list_empty(&irqs_to_free)){
- chan = list_entry(irqs_to_free.next, struct chan, free_list);
- list_del(&chan->free_list);
+ spin_lock_irq(&irqs_to_free_lock);
+ list_splice_init(&irqs_to_free, &list);
+ INIT_LIST_HEAD(&irqs_to_free);
+ spin_unlock_irq(&irqs_to_free_lock);
+
+ list_for_each(ele, &list){
+ chan = list_entry(ele, struct chan, free_list);
if(chan->input)
free_irq(chan->line->driver->read_irq, chan);
@@ -246,7 +259,9 @@
return;
if(delay_free_irq){
+ spin_lock_irq(&irqs_to_free_lock);
list_add(&chan->free_list, &irqs_to_free);
+ spin_unlock_irq(&irqs_to_free_lock);
}
else {
if(chan->input)