Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/gi…

…t/mst/vhost

Pull virtio fixes from Michael Tsirkin:
 "Some bugfixes that seem important and safe enough to merge at the last
  minute"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_balloon: fix another race between migration and ballooning
  tools/virtio: add kmalloc_array stub
  tools/virtio: add dma barrier stubs

drivers/virtio/virtio_balloon.c

@@ -513,7 +513,9 @@ static int virtballoon_migratepage(struct balloon_dev_info *vb_dev_info,
 	tell_host(vb, vb->inflate_vq);
 
 	/* balloon's page migration 2nd step -- deflate "page" */
+	spin_lock_irqsave(&vb_dev_info->pages_lock, flags);
 	balloon_page_delete(page);
+	spin_unlock_irqrestore(&vb_dev_info->pages_lock, flags);
 	vb->num_pfns = VIRTIO_BALLOON_PAGES_PER_PAGE;
 	set_page_pfns(vb, vb->pfns, page);
 	tell_host(vb, vb->deflate_vq);

tools/virtio/asm/barrier.h

@@ -13,8 +13,8 @@
 } while (0);
 /* Weak barriers should be used. If not - it's a bug */
 # define mb() abort()
-# define rmb() abort()
-# define wmb() abort()
+# define dma_rmb() abort()
+# define dma_wmb() abort()
 #else
 #error Please fill in barrier macros
 #endif

tools/virtio/linux/kernel.h

@@ -52,6 +52,11 @@ static inline void *kmalloc(size_t s, gfp_t gfp)
 		return __kmalloc_fake;
 	return malloc(s);
 }
+static inline void *kmalloc_array(unsigned n, size_t s, gfp_t gfp)
+{
+	return kmalloc(n * s, gfp);
+}
+
 static inline void *kzalloc(size_t s, gfp_t gfp)
 {
 	void *p = kmalloc(s, gfp);