drm/vmwgfx: Use memdup_user() rather than duplicating its implementation

* Reuse existing functionality from memdup_user() instead of keeping
  duplicate source code.

* Try this copy operation before allocating memory for the data structure
  member "offsets".

* Delete the local variable "user_sizes" which became unnecessary
  with this refactoring.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Sinclair Yeh <syeh@vmware.com>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index f557549..15504c6 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -700,7 +700,6 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
        struct drm_vmw_surface_create_req *req = &arg->req;
        struct drm_vmw_surface_arg *rep = &arg->rep;
        struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
-       struct drm_vmw_size __user *user_sizes;
        int ret;
        int i, j;
        uint32_t cur_bo_offset;
@@ -763,11 +762,11 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
        memcpy(srf->mip_levels, req->mip_levels, sizeof(srf->mip_levels));
        srf->num_sizes = num_sizes;
        user_srf->size = size;
-       srf->sizes = kmalloc_array(srf->num_sizes,
-                                  sizeof(*srf->sizes),
-                                  GFP_KERNEL);
-       if (unlikely(srf->sizes == NULL)) {
-               ret = -ENOMEM;
+       srf->sizes = memdup_user((struct drm_vmw_size __user *)(unsigned long)
+                                req->size_addr,
+                                sizeof(*srf->sizes) * srf->num_sizes);
+       if (IS_ERR(srf->sizes)) {
+               ret = PTR_ERR(srf->sizes);
                goto out_no_sizes;
        }
        srf->offsets = kmalloc_array(srf->num_sizes,
@@ -778,16 +777,6 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
                goto out_no_offsets;
        }
 
-       user_sizes = (struct drm_vmw_size __user *)(unsigned long)
-           req->size_addr;
-
-       ret = copy_from_user(srf->sizes, user_sizes,
-                            srf->num_sizes * sizeof(*srf->sizes));
-       if (unlikely(ret != 0)) {
-               ret = -EFAULT;
-               goto out_no_copy;
-       }
-
        srf->base_size = *srf->sizes;
        srf->autogen_filter = SVGA3D_TEX_FILTER_NONE;
        srf->multisample_count = 0;