drm/i915: check the return value from the copy from user

This produced a warning on my build, not sure why super-warning-man didn't
notice this one, its much worse than the %z one.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e5d2bdf2cc9b..e0389ad1477d 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -446,13 +446,16 @@ fast_shmem_write(struct page **pages,
                  int length)
 {
         char __iomem *vaddr;
+        unsigned long unwritten;
 
         vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT], KM_USER0);
         if (vaddr == NULL)
                 return -ENOMEM;
-        __copy_from_user_inatomic(vaddr + page_offset, data, length);
+        unwritten = __copy_from_user_inatomic(vaddr + page_offset, data, length);
         kunmap_atomic(vaddr, KM_USER0);
 
+        if (unwritten)
+                return -EFAULT;
         return 0;
 }