The existing for_each_sg_page() iterator is somewhat inconvenient; in particular, the 'nents' parameters is not expressed in any useful way, and so there is no way to get a precise (maximum) number of iterations (and therefore pages) without knowing that the SGL has been constructed in a specific way.
So here we introduce for_each_sgt_page(), which simplifies the parameters down to just two: the iterator and an sg_table to iterate over. This is ideal where we simply need to process *all* the pages, regardless of how many there might be (e.g. put_pages()). For more sophisticated uses, for_each_sgt_range() adds a starting (page) offset and a maximum number of iterations to be performed. This fits the usage required when processing only a subrange of the pages, or to avoid any risk of overflow when filling a bounded array with per-page data. Nearly all uses of for_each_sg_page() are then converted to the new simpler macros. Signed-off-by: Dave Gordon <[email protected]> Cc: Imre Deak <[email protected]> Cc: [email protected] --- drivers/gpu/drm/i915/i915_cmd_parser.c | 8 ++++---- drivers/gpu/drm/i915/i915_gem.c | 10 ++++------ drivers/gpu/drm/i915/i915_gem_fence.c | 5 +++-- drivers/gpu/drm/i915/i915_gem_gtt.c | 20 +++++++++----------- drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +- include/linux/scatterlist.h | 21 +++++++++++++++++++++ lib/scatterlist.c | 26 ++++++++++++++++++++++++++ 7 files changed, 68 insertions(+), 24 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c index c3a7603..4f08ab0 100644 --- a/drivers/gpu/drm/i915/i915_cmd_parser.c +++ b/drivers/gpu/drm/i915/i915_cmd_parser.c @@ -946,11 +946,11 @@ static u32 *vmap_batch(struct drm_i915_gem_object *obj, } i = 0; - for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, first_page) { + for_each_sgt_page_range(&sg_iter, obj->pages, first_page, npages) pages[i++] = sg_page_iter_page(&sg_iter); - if (i == npages) - break; - } + + if (WARN_ON(i != npages)) + goto finish; addr = vmap(pages, i, 0, PAGE_KERNEL); if (addr == NULL) { diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index a88e6c9..03b2ed3 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -611,8 +611,7 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj, offset = args->offset; - for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, - offset >> PAGE_SHIFT) { + for_each_sgt_page_range(&sg_iter, obj->pages, offset >> PAGE_SHIFT, ~0u) { struct page *page = sg_page_iter_page(&sg_iter); if (remain <= 0) @@ -935,8 +934,7 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj, offset = args->offset; obj->dirty = 1; - for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, - offset >> PAGE_SHIFT) { + for_each_sgt_page_range(&sg_iter, obj->pages, offset >> PAGE_SHIFT, ~0u) { struct page *page = sg_page_iter_page(&sg_iter); int partial_cacheline_write; @@ -2184,7 +2182,7 @@ static void i915_gem_object_free_mmap_offset(struct drm_i915_gem_object *obj) if (obj->madv == I915_MADV_DONTNEED) obj->dirty = 0; - for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) { + for_each_sgt_page(&sg_iter, obj->pages) { struct page *page = sg_page_iter_page(&sg_iter); if (obj->dirty) @@ -2340,7 +2338,7 @@ static void i915_gem_object_free_mmap_offset(struct drm_i915_gem_object *obj) err_pages: sg_mark_end(sg); - for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) + for_each_sgt_page(&sg_iter, st) put_page(sg_page_iter_page(&sg_iter)); sg_free_table(st); kfree(st); diff --git a/drivers/gpu/drm/i915/i915_gem_fence.c b/drivers/gpu/drm/i915/i915_gem_fence.c index a2b938e..4fb06f6 100644 --- a/drivers/gpu/drm/i915/i915_gem_fence.c +++ b/drivers/gpu/drm/i915/i915_gem_fence.c @@ -752,7 +752,7 @@ void i915_gem_restore_fences(struct drm_device *dev) return; i = 0; - for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) { + for_each_sgt_page(&sg_iter, obj->pages) { struct page *page = sg_page_iter_page(&sg_iter); char new_bit_17 = page_to_phys(page) >> 17; if ((new_bit_17 & 0x1) != @@ -790,7 +790,8 @@ void i915_gem_restore_fences(struct drm_device *dev) } i = 0; - for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) { + + for_each_sgt_page(&sg_iter, obj->pages) { if (page_to_phys(sg_page_iter_page(&sg_iter)) & (1 << 17)) __set_bit(i, obj->bit_17); else diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index d284b17..7296d02 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -1844,7 +1844,7 @@ static void gen6_ppgtt_insert_entries(struct i915_address_space *vm, struct sg_page_iter sg_iter; pt_vaddr = NULL; - for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) { + for_each_sgt_page(&sg_iter, pages) { if (pt_vaddr == NULL) pt_vaddr = kmap_px(ppgtt->pd.page_table[act_pt]); @@ -2371,7 +2371,7 @@ static void gen8_ggtt_insert_entries(struct i915_address_space *vm, rpm_atomic_seq = assert_rpm_atomic_begin(dev_priv); - for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) { + for_each_sgt_page(&sg_iter, st) { addr = sg_dma_address(sg_iter.sg) + (sg_iter.sg_pgoffset << PAGE_SHIFT); gen8_set_pte(>t_entries[i], @@ -2449,7 +2449,7 @@ static void gen6_ggtt_insert_entries(struct i915_address_space *vm, rpm_atomic_seq = assert_rpm_atomic_begin(dev_priv); - for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) { + for_each_sgt_page(&sg_iter, st) { addr = sg_page_iter_dma_address(&sg_iter); iowrite32(vm->pte_encode(addr, level, true, flags), >t_entries[i]); i++; @@ -3384,6 +3384,7 @@ struct i915_vma * intel_rotate_fb_obj_pages(struct intel_rotation_info *rot_info, struct drm_i915_gem_object *obj) { + unsigned int n_pages = obj->base.size / PAGE_SIZE; unsigned int size_pages = rot_info->plane[0].width * rot_info->plane[0].height; unsigned int size_pages_uv; struct sg_page_iter sg_iter; @@ -3395,7 +3396,7 @@ struct i915_vma * int ret = -ENOMEM; /* Allocate a temporary list of source pages for random access. */ - page_addr_list = drm_malloc_gfp(obj->base.size / PAGE_SIZE, + page_addr_list = drm_malloc_gfp(n_pages, sizeof(dma_addr_t), GFP_TEMPORARY); if (!page_addr_list) @@ -3418,11 +3419,10 @@ struct i915_vma * /* Populate source page list from the object. */ i = 0; - for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) { - page_addr_list[i] = sg_page_iter_dma_address(&sg_iter); - i++; - } + for_each_sgt_page_range(&sg_iter, obj->pages, 0, n_pages) + page_addr_list[i++] = sg_page_iter_dma_address(&sg_iter); + WARN_ON(i != n_pages); st->nents = 0; sg = st->sgl; @@ -3488,9 +3488,7 @@ struct i915_vma * sg = st->sgl; st->nents = 0; - for_each_sg_page(obj->pages->sgl, &obj_sg_iter, obj->pages->nents, - view->params.partial.offset) - { + for_each_sgt_page_range(&obj_sg_iter, obj->pages, view->params.partial.offset, ~0u) { if (st->nents >= view->params.partial.size) break; diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index 32d9726..3d5e4a9 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -716,7 +716,7 @@ struct get_pages_work { i915_gem_gtt_finish_object(obj); - for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) { + for_each_sgt_page(&sg_iter, obj->pages) { struct page *page = sg_page_iter_page(&sg_iter); if (obj->dirty) diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 556ec1e..2755f16 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -305,6 +305,7 @@ struct sg_page_iter { * next step */ }; +bool __sgt_page_iter_next(struct sg_page_iter *piter); bool __sg_page_iter_next(struct sg_page_iter *piter); void __sg_page_iter_start(struct sg_page_iter *piter, struct scatterlist *sglist, unsigned int nents, @@ -339,6 +340,26 @@ static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter) for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ __sg_page_iter_next(piter);) +/** + * for_each_sgt_page - iterate over the pages of the given sg_table + * @piter: page iterator to hold current page, sg, sg_pgoffset + * @sgt: sg_table to iterate over + */ +#define for_each_sgt_page(piter, sgt) \ + for (__sg_page_iter_start((piter), (sgt)->sgl, (~0u), (0)); \ + __sgt_page_iter_next(piter);) + +/** + * for_each_sgt_page_range - iterate over some pages of the given sg_table + * @piter: page iterator to hold current page, sg, sg_pgoffset + * @sgt: sg_table to iterate over + * @first: starting page offset + * @max: maxiumum number of pages to iterate over + */ +#define for_each_sgt_page_range(piter, sgt, first, max) \ + for (__sg_page_iter_start((piter), (sgt)->sgl, (max), (first)); \ + __sgt_page_iter_next(piter);) + /* * Mapping sg iterator * diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 004fc70..ceeea63 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -469,6 +469,32 @@ bool __sg_page_iter_next(struct sg_page_iter *piter) } EXPORT_SYMBOL(__sg_page_iter_next); +/* + * Note: we use the same iterator structure as __sg_page_iter_next() + * above, but interpret the 'nents' member differently. Here it is + * an upper bound on the number of iterations to be performed, not + * the number of internal list elements to be traversed. + */ +bool __sgt_page_iter_next(struct sg_page_iter *piter) +{ + if (!piter->__nents || !piter->sg) + return false; + + piter->sg_pgoffset += piter->__pg_advance; + piter->__pg_advance = 1; + + while (piter->sg_pgoffset >= sg_page_count(piter->sg)) { + piter->sg_pgoffset -= sg_page_count(piter->sg); + piter->sg = sg_next(piter->sg); + if (!piter->sg) + return false; + } + + --piter->__nents; + return true; +} +EXPORT_SYMBOL(__sgt_page_iter_next); + /** * sg_miter_start - start mapping iteration over a sg list * @miter: sg mapping iter to be started -- 1.9.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
