Update to 3.4-final.

[linux-flexiantxendom0-3.2.10.git] / drivers / virtio / virtio_balloon.c

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 3368cb6..8807fe5 100644 (file)
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -28,6 +28,13 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 
+/*
+ * Balloon device works in 4K page units.  So each page is pointed to by
+ * multiple balloon pages.  All memory counters in this driver are in balloon
+ * page units.
+ */
+#define VIRTIO_BALLOON_PAGES_PER_PAGE (PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT)
+
 struct virtio_balloon
 {
        struct virtio_device *vdev;
@@ -42,8 +49,13 @@ struct virtio_balloon
        /* Waiting for host to ack the pages we released. */
        struct completion acked;
 
-       /* The pages we've told the Host we're not using. */
+       /* Number of balloon pages we've told the Host we're not using. */
        unsigned int num_pages;
+       /*
+        * The pages we've told the Host we're not using.
+        * Each page on this list adds VIRTIO_BALLOON_PAGES_PER_PAGE
+        * to num_pages above.
+        */
        struct list_head pages;
 
        /* The array of pfns we tell the Host about. */
@@ -66,7 +78,13 @@ static u32 page_to_balloon_pfn(struct page *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);
+       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)
@@ -96,12 +114,23 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq)
        wait_for_completion(&vb->acked);
 }
 
+static void set_page_pfns(u32 pfns[], struct page *page)
+{
+       unsigned int i;
+
+       /* 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] = page_to_balloon_pfn(page) + i;
+}
+
 static void fill_balloon(struct virtio_balloon *vb, size_t num)
 {
        /* We can only do one array worth at a time. */
        num = min(num, ARRAY_SIZE(vb->pfns));
 
-       for (vb->num_pfns = 0; vb->num_pfns < num; vb->num_pfns++) {
+       for (vb->num_pfns = 0; vb->num_pfns < num;
+            vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
                struct page *page = alloc_page(GFP_HIGHUSER | __GFP_NORETRY |
                                        __GFP_NOMEMALLOC | __GFP_NOWARN);
                if (!page) {
@@ -113,9 +142,9 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
                        msleep(200);
                        break;
                }
-               vb->pfns[vb->num_pfns] = page_to_balloon_pfn(page);
+               set_page_pfns(vb->pfns + vb->num_pfns, page);
+               vb->num_pages += VIRTIO_BALLOON_PAGES_PER_PAGE;
                totalram_pages--;
-               vb->num_pages++;
                list_add(&page->lru, &vb->pages);
        }
 
@@ -130,8 +159,9 @@ static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
 {
        unsigned int i;
 
-       for (i = 0; i < num; i++) {
-               __free_page(pfn_to_page(pfns[i]));
+       /* Find pfns pointing at start of each page, get pages and free them. */
+       for (i = 0; i < num; i += VIRTIO_BALLOON_PAGES_PER_PAGE) {
+               __free_page(balloon_pfn_to_page(pfns[i]));
                totalram_pages++;
        }
 }
@@ -143,11 +173,12 @@ static void leak_balloon(struct virtio_balloon *vb, size_t num)
        /* We can only do one array worth at a time. */
        num = min(num, ARRAY_SIZE(vb->pfns));
 
-       for (vb->num_pfns = 0; vb->num_pfns < num; vb->num_pfns++) {
+       for (vb->num_pfns = 0; vb->num_pfns < num;
+            vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
                page = list_first_entry(&vb->pages, struct page, lru);
                list_del(&page->lru);
-               vb->pfns[vb->num_pfns] = page_to_balloon_pfn(page);
-               vb->num_pages--;
+               set_page_pfns(vb->pfns + vb->num_pfns, page);
+               vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE;
        }
 
        /*
@@ -234,11 +265,14 @@ static void virtballoon_changed(struct virtio_device *vdev)
 
 static inline s64 towards_target(struct virtio_balloon *vb)
 {
-       u32 v;
+       __le32 v;
+       s64 target;
+
        vb->vdev->config->get(vb->vdev,
                              offsetof(struct virtio_balloon_config, num_pages),
                              &v, sizeof(v));
-       return (s64)v - vb->num_pages;
+       target = le32_to_cpu(v);
+       return target - vb->num_pages;
 }
 
 static void update_balloon_size(struct virtio_balloon *vb)
@@ -356,6 +390,7 @@ static void __devexit virtballoon_remove(struct virtio_device *vdev)
        /* There might be pages left in the balloon: free them. */
        while (vb->num_pages)
                leak_balloon(vb, vb->num_pages);
+       update_balloon_size(vb);
 
        /* Now we reset the device so we can clean up the queues. */
        vdev->config->reset(vdev);
@@ -364,6 +399,46 @@ static void __devexit virtballoon_remove(struct virtio_device *vdev)
        kfree(vb);
 }
 
+#ifdef CONFIG_PM
+static int virtballoon_freeze(struct virtio_device *vdev)
+{
+       struct virtio_balloon *vb = vdev->priv;
+
+       /*
+        * The kthread is already frozen by the PM core before this
+        * function is called.
+        */
+
+       while (vb->num_pages)
+               leak_balloon(vb, vb->num_pages);
+       update_balloon_size(vb);
+
+       /* Ensure we don't get any more requests from the host */
+       vdev->config->reset(vdev);
+       vdev->config->del_vqs(vdev);
+       return 0;
+}
+
+static int restore_common(struct virtio_device *vdev)
+{
+       struct virtio_balloon *vb = vdev->priv;
+       int ret;
+
+       ret = init_vqs(vdev->priv);
+       if (ret)
+               return ret;
+
+       fill_balloon(vb, towards_target(vb));
+       update_balloon_size(vb);
+       return 0;
+}
+
+static int virtballoon_restore(struct virtio_device *vdev)
+{
+       return restore_common(vdev);
+}
+#endif
+
 static unsigned int features[] = {
        VIRTIO_BALLOON_F_MUST_TELL_HOST,
        VIRTIO_BALLOON_F_STATS_VQ,
@@ -378,6 +453,10 @@ static struct virtio_driver virtio_balloon_driver = {
        .probe =        virtballoon_probe,
        .remove =       __devexit_p(virtballoon_remove),
        .config_changed = virtballoon_changed,
+#ifdef CONFIG_PM
+       .freeze =       virtballoon_freeze,
+       .restore =      virtballoon_restore,
+#endif
 };
 
 static int __init init(void)