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Diffstat (limited to 'block/blk-ioc.c')
-rw-r--r--block/blk-ioc.c42
1 files changed, 21 insertions, 21 deletions
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 9df50fb507ca..57299f860d41 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -96,15 +96,7 @@ static void ioc_release_fn(struct work_struct *work)
{
struct io_context *ioc = container_of(work, struct io_context,
release_work);
- unsigned long flags;
-
- /*
- * Exiting icq may call into put_io_context() through elevator
- * which will trigger lockdep warning. The ioc's are guaranteed to
- * be different, use a different locking subclass here. Use
- * irqsave variant as there's no spin_lock_irq_nested().
- */
- spin_lock_irqsave_nested(&ioc->lock, flags, 1);
+ spin_lock_irq(&ioc->lock);
while (!hlist_empty(&ioc->icq_list)) {
struct io_cq *icq = hlist_entry(ioc->icq_list.first,
@@ -115,13 +107,27 @@ static void ioc_release_fn(struct work_struct *work)
ioc_destroy_icq(icq);
spin_unlock(&q->queue_lock);
} else {
- spin_unlock_irqrestore(&ioc->lock, flags);
- cpu_relax();
- spin_lock_irqsave_nested(&ioc->lock, flags, 1);
+ /* Make sure q and icq cannot be freed. */
+ rcu_read_lock();
+
+ /* Re-acquire the locks in the correct order. */
+ spin_unlock(&ioc->lock);
+ spin_lock(&q->queue_lock);
+ spin_lock(&ioc->lock);
+
+ /*
+ * The icq may have been destroyed when the ioc lock
+ * was released.
+ */
+ if (!(icq->flags & ICQ_DESTROYED))
+ ioc_destroy_icq(icq);
+
+ spin_unlock(&q->queue_lock);
+ rcu_read_unlock();
}
}
- spin_unlock_irqrestore(&ioc->lock, flags);
+ spin_unlock_irq(&ioc->lock);
kmem_cache_free(iocontext_cachep, ioc);
}
@@ -170,7 +176,6 @@ void put_io_context(struct io_context *ioc)
*/
void put_io_context_active(struct io_context *ioc)
{
- unsigned long flags;
struct io_cq *icq;
if (!atomic_dec_and_test(&ioc->active_ref)) {
@@ -178,19 +183,14 @@ void put_io_context_active(struct io_context *ioc)
return;
}
- /*
- * Need ioc lock to walk icq_list and q lock to exit icq. Perform
- * reverse double locking. Read comment in ioc_release_fn() for
- * explanation on the nested locking annotation.
- */
- spin_lock_irqsave_nested(&ioc->lock, flags, 1);
+ spin_lock_irq(&ioc->lock);
hlist_for_each_entry(icq, &ioc->icq_list, ioc_node) {
if (icq->flags & ICQ_EXITED)
continue;
ioc_exit_icq(icq);
}
- spin_unlock_irqrestore(&ioc->lock, flags);
+ spin_unlock_irq(&ioc->lock);
put_io_context(ioc);
}