drivers/gpu/drm/i915/i915_scatterlist.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright © 2016 Intel Corporation
   5  */
   6
   7 #include "i915_scatterlist.h"
   8
   9 bool i915_sg_trim(struct sg_table *orig_st)
  10 {
  11         struct sg_table new_st;
  12         struct scatterlist *sg, *new_sg;
  13         unsigned int i;
  14
  15         if (orig_st->nents == orig_st->orig_nents)
  16                 return false;
  17
  18         if (sg_alloc_table(&new_st, orig_st->nents, GFP_KERNEL | __GFP_NOWARN))
  19                 return false;
  20
  21         new_sg = new_st.sgl;
  22         for_each_sg(orig_st->sgl, sg, orig_st->nents, i) {
  23                 sg_set_page(new_sg, sg_page(sg), sg->length, 0);
  24                 sg_dma_address(new_sg) = sg_dma_address(sg);
  25                 sg_dma_len(new_sg) = sg_dma_len(sg);
  26
  27                 new_sg = sg_next(new_sg);
  28         }
  29         GEM_BUG_ON(new_sg); /* Should walk exactly nents and hit the end */
  30
  31         sg_free_table(orig_st);
  32
  33         *orig_st = new_st;
  34         return true;
  35 }
  36
  37 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
  38 #include "selftests/scatterlist.c"
  39 #endif