Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt...

[safe/jmp/linux-2.6] / drivers / virtio / virtio_balloon.c

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index bfef604..5926826 100644 (file)
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -56,6 +56,15 @@ static struct virtio_device_id id_table[] = {
        { 0 },
 };
 
+static u32 page_to_balloon_pfn(struct page *page)
+{
+       unsigned long pfn = page_to_pfn(page);
+
+       BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT);
+       /* Convert pfn from Linux page size to balloon page size. */
+       return pfn >> (PAGE_SHIFT - VIRTIO_BALLOON_PFN_SHIFT);
+}
+
 static void balloon_ack(struct virtqueue *vq)
 {
        struct virtio_balloon *vb;
@@ -99,7 +108,7 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
                        msleep(200);
                        break;
                }
-               vb->pfns[vb->num_pfns] = page_to_pfn(page);
+               vb->pfns[vb->num_pfns] = page_to_balloon_pfn(page);
                totalram_pages--;
                vb->num_pages++;
                list_add(&page->lru, &vb->pages);
@@ -132,7 +141,7 @@ static void leak_balloon(struct virtio_balloon *vb, size_t num)
        for (vb->num_pfns = 0; vb->num_pfns < num; vb->num_pfns++) {
                page = list_first_entry(&vb->pages, struct page, lru);
                list_del(&page->lru);
-               vb->pfns[vb->num_pfns] = page_to_pfn(page);
+               vb->pfns[vb->num_pfns] = page_to_balloon_pfn(page);
                vb->num_pages--;
        }
 
@@ -158,7 +167,7 @@ static inline s64 towards_target(struct virtio_balloon *vb)
        vb->vdev->config->get(vb->vdev,
                              offsetof(struct virtio_balloon_config, num_pages),
                              &v, sizeof(v));
-       return v - vb->num_pages;
+       return (s64)v - vb->num_pages;
 }
 
 static void update_balloon_size(struct virtio_balloon *vb)