1 files changed, 18 insertions, 2 deletions

diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index 08adc590f631..597af455a522 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -55,6 +55,7 @@
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/miscdevice.h>
+#include <linux/workqueue.h>
 
 #include <xen/xenbus.h>
 #include <xen/xen.h>
@@ -116,6 +117,8 @@ struct xenbus_file_priv {
         wait_queue_head_t read_waitq;
 
         struct kref kref;
+
+        struct work_struct wq;
 };
 
 /* Read out any raw xenbus messages queued up. */
@@ -300,14 +303,14 @@ static void watch_fired(struct xenbus_watch *watch,
         mutex_unlock(&adap->dev_data->reply_mutex);
 }
 
-static void xenbus_file_free(struct kref *kref)
+static void xenbus_worker(struct work_struct *wq)
 {
         struct xenbus_file_priv *u;
         struct xenbus_transaction_holder *trans, *tmp;
         struct watch_adapter *watch, *tmp_watch;
         struct read_buffer *rb, *tmp_rb;
 
-        u = container_of(kref, struct xenbus_file_priv, kref);
+        u = container_of(wq, struct xenbus_file_priv, wq);
 
         /*
          * No need for locking here because there are no other users,
@@ -333,6 +336,18 @@ static void xenbus_file_free(struct kref *kref)
         kfree(u);
 }
 
+static void xenbus_file_free(struct kref *kref)
+{
+        struct xenbus_file_priv *u;
+
+        /*
+         * We might be called in xenbus_thread().
+         * Use workqueue to avoid deadlock.
+         */
+        u = container_of(kref, struct xenbus_file_priv, kref);
+        schedule_work(&u->wq);
+}
+
 static struct xenbus_transaction_holder *xenbus_get_transaction(
         struct xenbus_file_priv *u, uint32_t tx_id)
 {
@@ -650,6 +665,7 @@ static int xenbus_file_open(struct inode *inode, struct file *filp)
         INIT_LIST_HEAD(&u->watches);
         INIT_LIST_HEAD(&u->read_buffers);
         init_waitqueue_head(&u->read_waitq);
+        INIT_WORK(&u->wq, xenbus_worker);
 
         mutex_init(&u->reply_mutex);
         mutex_init(&u->msgbuffer_mutex);