drm/i915: Fix up address spaces in slow_kernel_write()

Since we now get_user_pages() outside of the mutex prior to performing
the copy, we kmap() the page inside the copy routine and so need to
perform an ordinary memcpy() and not copy_from_user().

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index b8e3512744931e934722616644a207861a395a7c..9ded3dae6c87105cdd7acaa65d5548aeb90dfee3 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -509,25 +509,24 @@ fast_user_write(struct io_mapping *mapping,
  * page faults
  */
 
-static inline int
+static inline void
 slow_kernel_write(struct io_mapping *mapping,
                  loff_t gtt_base, int gtt_offset,
                  struct page *user_page, int user_offset,
                  int length)
 {
-       char *src_vaddr, *dst_vaddr;
-       unsigned long unwritten;
+       char __iomem *dst_vaddr;
+       char *src_vaddr;
 
-       dst_vaddr = io_mapping_map_atomic_wc(mapping, gtt_base);
-       src_vaddr = kmap_atomic(user_page, KM_USER1);
-       unwritten = __copy_from_user_inatomic_nocache(dst_vaddr + gtt_offset,
-                                                     src_vaddr + user_offset,
-                                                     length);
-       kunmap_atomic(src_vaddr, KM_USER1);
-       io_mapping_unmap_atomic(dst_vaddr);
-       if (unwritten)
-               return -EFAULT;
-       return 0;
+       dst_vaddr = io_mapping_map_wc(mapping, gtt_base);
+       src_vaddr = kmap(user_page);
+
+       memcpy_toio(dst_vaddr + gtt_offset,
+                   src_vaddr + user_offset,
+                   length);
+
+       kunmap(user_page);
+       io_mapping_unmap(dst_vaddr);
 }
 
 static inline int
@@ -700,18 +699,11 @@ i915_gem_gtt_pwrite_slow(struct drm_device *dev, struct drm_gem_object *obj,
                if ((data_page_offset + page_length) > PAGE_SIZE)
                        page_length = PAGE_SIZE - data_page_offset;
 
-               ret = slow_kernel_write(dev_priv->mm.gtt_mapping,
-                                       gtt_page_base, gtt_page_offset,
-                                       user_pages[data_page_index],
-                                       data_page_offset,
-                                       page_length);
-
-               /* If we get a fault while copying data, then (presumably) our
-                * source page isn't available.  Return the error and we'll
-                * retry in the slow path.
-                */
-               if (ret)
-                       goto out_unpin_object;
+               slow_kernel_write(dev_priv->mm.gtt_mapping,
+                                 gtt_page_base, gtt_page_offset,
+                                 user_pages[data_page_index],
+                                 data_page_offset,
+                                 page_length);
 
                remain -= page_length;
                offset += page_length;