---

yaml
---
r: 284243
b: refs/heads/master
c: 4678d6f
h: refs/heads/master
i:
  284241: a04fe85
  284239: b8de77c
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e93300b1afc7cd4fe1e741ceaf06714d060e88b8
+refs/heads/master: 4678d6f970c2f7c0cbfefc0cc666432d153b321b

trunk/drivers/block/virtio_blk.c

@@ -4,6 +4,7 @@
 #include <linux/blkdev.h>
 #include <linux/hdreg.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/virtio.h>
 #include <linux/virtio_blk.h>
 #include <linux/scatterlist.h>
@@ -36,6 +37,12 @@ struct virtio_blk
 	/* Process context for config space updates */
 	struct work_struct config_work;
 
+	/* Lock for config space updates */
+	struct mutex config_lock;
+
+	/* enable config space updates */
+	bool config_enable;
+
 	/* What host tells us, plus 2 for header & tailer. */
 	unsigned int sg_elems;
 
@@ -318,6 +325,10 @@ static void virtblk_config_changed_work(struct work_struct *work)
 	char cap_str_2[10], cap_str_10[10];
 	u64 capacity, size;
 
+	mutex_lock(&vblk->config_lock);
+	if (!vblk->config_enable)
+		goto done;
+
 	/* Host must always specify the capacity. */
 	vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity),
 			  &capacity, sizeof(capacity));
@@ -340,6 +351,8 @@ static void virtblk_config_changed_work(struct work_struct *work)
 		  cap_str_10, cap_str_2);
 
 	set_capacity(vblk->disk, capacity);
+done:
+	mutex_unlock(&vblk->config_lock);
 }
 
 static void virtblk_config_changed(struct virtio_device *vdev)
@@ -388,7 +401,9 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
 	vblk->vdev = vdev;
 	vblk->sg_elems = sg_elems;
 	sg_init_table(vblk->sg, vblk->sg_elems);
+	mutex_init(&vblk->config_lock);
 	INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
+	vblk->config_enable = true;
 
 	/* We expect one virtqueue, for output. */
 	vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
@@ -542,14 +557,19 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
 	struct virtio_blk *vblk = vdev->priv;
 	int index = vblk->index;
 
-	flush_work(&vblk->config_work);
+	/* Prevent config work handler from accessing the device. */
+	mutex_lock(&vblk->config_lock);
+	vblk->config_enable = false;
+	mutex_unlock(&vblk->config_lock);
 
 	/* Nothing should be pending. */
 	BUG_ON(!list_empty(&vblk->reqs));
 
 	/* Stop all the virtqueues. */
 	vdev->config->reset(vdev);
 
+	flush_work(&vblk->config_work);
+
 	del_gendisk(vblk->disk);
 	blk_cleanup_queue(vblk->disk->queue);
 	put_disk(vblk->disk);