Merge tag 'stable/for-linus-3.7-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen bugfixes from Konrad Rzeszutek Wilk:
 - Use appropriate macros instead of hand-rolling our own (ARM).
 - Fixes if FB/KBD closed unexpectedly.
 - Fix memory leak in /dev/gntdev ioctl calls.
 - Fix overflow check in xenbus_file_write.
 - Document cleanup.
 - Performance optimization when migrating guests.

* tag 'stable/for-linus-3.7-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/mmu: Use Xen specific TLB flush instead of the generic one.
  xen/arm: use the __HVC macro
  xen/xenbus: fix overflow check in xenbus_file_write()
  xen-kbdfront: handle backend CLOSED without CLOSING
  xen-fbfront: handle backend CLOSED without CLOSING
  xen/gntdev: don't leak memory from IOCTL_GNTDEV_MAP_GRANT_REF
  x86: remove obsolete comment from asm/xen/hypervisor.h

2 files changed, 20 insertions, 18 deletions

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 610bfc6be177..2e22df2f7a3f 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -105,6 +105,21 @@ static void gntdev_print_maps(struct gntdev_priv *priv,
 #endif
 }
 
+static void gntdev_free_map(struct grant_map *map)
+{
+        if (map == NULL)
+                return;
+
+        if (map->pages)
+                free_xenballooned_pages(map->count, map->pages);
+        kfree(map->pages);
+        kfree(map->grants);
+        kfree(map->map_ops);
+        kfree(map->unmap_ops);
+        kfree(map->kmap_ops);
+        kfree(map);
+}
+
 static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
 {
         struct grant_map *add;
@@ -142,12 +157,7 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
         return add;
 
 err:
-        kfree(add->pages);
-        kfree(add->grants);
-        kfree(add->map_ops);
-        kfree(add->unmap_ops);
-        kfree(add->kmap_ops);
-        kfree(add);
+        gntdev_free_map(add);
         return NULL;
 }
 
@@ -198,17 +208,9 @@ static void gntdev_put_map(struct grant_map *map)
                 evtchn_put(map->notify.event);
         }
 
-        if (map->pages) {
-                if (!use_ptemod)
-                        unmap_grant_pages(map, 0, map->count);
-
-                free_xenballooned_pages(map->count, map->pages);
-        }
-        kfree(map->pages);
-        kfree(map->grants);
-        kfree(map->map_ops);
-        kfree(map->unmap_ops);
-        kfree(map);
+        if (map->pages && !use_ptemod)
+                unmap_grant_pages(map, 0, map->count);
+        gntdev_free_map(map);
 }
 
 /* ------------------------------------------------------------------ */
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index 89f76252a16f..ac727028e658 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -458,7 +458,7 @@ static ssize_t xenbus_file_write(struct file *filp,
                 goto out;
 
         /* Can't write a xenbus message larger we can buffer */
-        if ((len + u->len) > sizeof(u->u.buffer)) {
+        if (len > sizeof(u->u.buffer) - u->len) {
                 /* On error, dump existing buffer */
                 u->len = 0;
                 rc = -EINVAL;