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 40