Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio fixes and cleanups from Michael Tsirkin:
 "Fixes some minor issues all over the codebase"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio-net: fix module unloading
  virtio-balloon: coding format cleanup
  virtio-balloon: deflate via a page list
  virtio_blk: Use sysfs_match_string() helper

Author: torvalds

drivers/block/virtio_blk.c

@@ -541,12 +541,9 @@ virtblk_cache_type_store(struct device *dev, struct device_attribute *attr,
 	int i;
 
 	BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE));
-	for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; )
-		if (sysfs_streq(buf, virtblk_cache_types[i]))
-			break;
-
+	i = sysfs_match_string(virtblk_cache_types, buf);
 	if (i < 0)
-		return -EINVAL;
+		return i;
 
 	virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i);
 	virtblk_update_cache_mode(vdev);

drivers/net/virtio_net.c

@@ -2743,9 +2743,9 @@ module_init(virtio_net_driver_init);
 
 static __exit void virtio_net_driver_exit(void)
 {
+	unregister_virtio_driver(&virtio_net_driver);
 	cpuhp_remove_multi_state(CPUHP_VIRT_NET_DEAD);
 	cpuhp_remove_multi_state(virtionet_online);
-	unregister_virtio_driver(&virtio_net_driver);
 }
 module_exit(virtio_net_driver_exit);
 

drivers/virtio/virtio_balloon.c

@@ -104,12 +104,6 @@ static u32 page_to_balloon_pfn(struct page *page)
 	return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE;
 }
 
-static struct page *balloon_pfn_to_page(u32 pfn)
-{
-	BUG_ON(pfn % VIRTIO_BALLOON_PAGES_PER_PAGE);
-	return pfn_to_page(pfn / VIRTIO_BALLOON_PAGES_PER_PAGE);
-}
-
 static void balloon_ack(struct virtqueue *vq)
 {
 	struct virtio_balloon *vb = vq->vdev->priv;
@@ -138,8 +132,10 @@ static void set_page_pfns(struct virtio_balloon *vb,
 {
 	unsigned int i;
 
-	/* Set balloon pfns pointing at this page.
-	 * Note that the first pfn points at start of the page. */
+	/*
+	 * Set balloon pfns pointing at this page.
+	 * Note that the first pfn points at start of the page.
+	 */
 	for (i = 0; i < VIRTIO_BALLOON_PAGES_PER_PAGE; i++)
 		pfns[i] = cpu_to_virtio32(vb->vdev,
 					  page_to_balloon_pfn(page) + i);
@@ -182,18 +178,16 @@ static unsigned fill_balloon(struct virtio_balloon *vb, size_t num)
 	return num_allocated_pages;
 }
 
-static void release_pages_balloon(struct virtio_balloon *vb)
+static void release_pages_balloon(struct virtio_balloon *vb,
+				 struct list_head *pages)
 {
-	unsigned int i;
-	struct page *page;
+	struct page *page, *next;
 
-	/* Find pfns pointing at start of each page, get pages and free them. */
-	for (i = 0; i < vb->num_pfns; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
-		page = balloon_pfn_to_page(virtio32_to_cpu(vb->vdev,
-							   vb->pfns[i]));
+	list_for_each_entry_safe(page, next, pages, lru) {
 		if (!virtio_has_feature(vb->vdev,
 					VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
 			adjust_managed_page_count(page, 1);
+		list_del(&page->lru);
 		put_page(page); /* balloon reference */
 	}
 }
@@ -203,6 +197,7 @@ static unsigned leak_balloon(struct virtio_balloon *vb, size_t num)
 	unsigned num_freed_pages;
 	struct page *page;
 	struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info;
+	LIST_HEAD(pages);
 
 	/* We can only do one array worth at a time. */
 	num = min(num, ARRAY_SIZE(vb->pfns));
@@ -216,6 +211,7 @@ static unsigned leak_balloon(struct virtio_balloon *vb, size_t num)
 		if (!page)
 			break;
 		set_page_pfns(vb, vb->pfns + vb->num_pfns, page);
+		list_add(&page->lru, &pages);
 		vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE;
 	}
 
@@ -227,7 +223,7 @@ static unsigned leak_balloon(struct virtio_balloon *vb, size_t num)
 	 */
 	if (vb->num_pfns != 0)
 		tell_host(vb, vb->deflate_vq);
-	release_pages_balloon(vb);
+	release_pages_balloon(vb, &pages);
 	mutex_unlock(&vb->balloon_lock);
 	return num_freed_pages;
 }