drm/i915/ttm: Reorganize the ttm move code somewhat

In order to make the code a bit more readable and to facilitate
async memcpy moves, reorganize the move code a little. Determine
at an early stage whether to copy or to clear.

v2:
- Don't set up the memcpy iterators unless we are actually going to memcpy.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://lore.kernel.org/r/20210813144331.372957-2-thomas.hellstrom@linux.intel.com
Link: https://patchwork.freedesktop.org/patch/msgid/20210813144331.372957-2-thomas.hellstrom@linux.intel.com

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 771eb29..d07de18 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -431,6 +431,7 @@ i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
 }
 
 static int i915_ttm_accel_move(struct ttm_buffer_object *bo,
+                              bool clear,
                               struct ttm_resource *dst_mem,
                               struct sg_table *dst_st)
 {
@@ -449,13 +450,10 @@ static int i915_ttm_accel_move(struct ttm_buffer_object *bo,
                return -EINVAL;
 
        dst_level = i915_ttm_cache_level(i915, dst_mem, ttm);
-       if (!ttm || !ttm_tt_is_populated(ttm)) {
+       if (clear) {
                if (bo->type == ttm_bo_type_kernel)
                        return -EINVAL;
 
-               if (ttm && !(ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC))
-                       return 0;
-
                intel_engine_pm_get(i915->gt.migrate.context->engine);
                ret = intel_context_migrate_clear(i915->gt.migrate.context, NULL,
                                                  dst_st->sgl, dst_level,
@@ -489,6 +487,41 @@ static int i915_ttm_accel_move(struct ttm_buffer_object *bo,
        return ret;
 }
 
+static void __i915_ttm_move(struct ttm_buffer_object *bo, bool clear,
+                           struct ttm_resource *dst_mem,
+                           struct sg_table *dst_st)
+{
+       int ret;
+
+       ret = i915_ttm_accel_move(bo, clear, dst_mem, dst_st);
+       if (ret) {
+               struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
+               struct intel_memory_region *dst_reg, *src_reg;
+               union {
+                       struct ttm_kmap_iter_tt tt;
+                       struct ttm_kmap_iter_iomap io;
+               } _dst_iter, _src_iter;
+               struct ttm_kmap_iter *dst_iter, *src_iter;
+
+               dst_reg = i915_ttm_region(bo->bdev, dst_mem->mem_type);
+               src_reg = i915_ttm_region(bo->bdev, bo->resource->mem_type);
+               GEM_BUG_ON(!dst_reg || !src_reg);
+
+               dst_iter = !cpu_maps_iomem(dst_mem) ?
+                       ttm_kmap_iter_tt_init(&_dst_iter.tt, bo->ttm) :
+                       ttm_kmap_iter_iomap_init(&_dst_iter.io, &dst_reg->iomap,
+                                                dst_st, dst_reg->region.start);
+
+               src_iter = !cpu_maps_iomem(bo->resource) ?
+                       ttm_kmap_iter_tt_init(&_src_iter.tt, bo->ttm) :
+                       ttm_kmap_iter_iomap_init(&_src_iter.io, &src_reg->iomap,
+                                                obj->ttm.cached_io_st,
+                                                src_reg->region.start);
+
+               ttm_move_memcpy(bo, dst_mem->num_pages, dst_iter, src_iter);
+       }
+}
+
 static int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
                         struct ttm_operation_ctx *ctx,
                         struct ttm_resource *dst_mem,
@@ -497,19 +530,11 @@ static int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
        struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
        struct ttm_resource_manager *dst_man =
                ttm_manager_type(bo->bdev, dst_mem->mem_type);
-       struct intel_memory_region *dst_reg, *src_reg;
-       union {
-               struct ttm_kmap_iter_tt tt;
-               struct ttm_kmap_iter_iomap io;
-       } _dst_iter, _src_iter;
-       struct ttm_kmap_iter *dst_iter, *src_iter;
+       struct ttm_tt *ttm = bo->ttm;
        struct sg_table *dst_st;
+       bool clear;
        int ret;
 
-       dst_reg = i915_ttm_region(bo->bdev, dst_mem->mem_type);
-       src_reg = i915_ttm_region(bo->bdev, bo->resource->mem_type);
-       GEM_BUG_ON(!dst_reg || !src_reg);
-
        /* Sync for now. We could do the actual copy async. */
        ret = ttm_bo_wait_ctx(bo, ctx);
        if (ret)
@@ -526,9 +551,8 @@ static int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
        }
 
        /* Populate ttm with pages if needed. Typically system memory. */
-       if (bo->ttm && (dst_man->use_tt ||
-                       (bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED))) {
-               ret = ttm_tt_populate(bo->bdev, bo->ttm, ctx);
+       if (ttm && (dst_man->use_tt || (ttm->page_flags & TTM_PAGE_FLAG_SWAPPED))) {
+               ret = ttm_tt_populate(bo->bdev, ttm, ctx);
                if (ret)
                        return ret;
        }
@@ -537,23 +561,10 @@ static int i915_ttm_move(struct ttm_buffer_object *bo, bool evict,
        if (IS_ERR(dst_st))
                return PTR_ERR(dst_st);
 
-       ret = i915_ttm_accel_move(bo, dst_mem, dst_st);
-       if (ret) {
-               /* If we start mapping GGTT, we can no longer use man::use_tt here. */
-               dst_iter = !cpu_maps_iomem(dst_mem) ?
-                       ttm_kmap_iter_tt_init(&_dst_iter.tt, bo->ttm) :
-                       ttm_kmap_iter_iomap_init(&_dst_iter.io, &dst_reg->iomap,
-                                                dst_st, dst_reg->region.start);
-
-               src_iter = !cpu_maps_iomem(bo->resource) ?
-                       ttm_kmap_iter_tt_init(&_src_iter.tt, bo->ttm) :
-                       ttm_kmap_iter_iomap_init(&_src_iter.io, &src_reg->iomap,
-                                                obj->ttm.cached_io_st,
-                                                src_reg->region.start);
+       clear = !cpu_maps_iomem(bo->resource) && (!ttm || !ttm_tt_is_populated(ttm));
+       if (!(clear && ttm && !(ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)))
+               __i915_ttm_move(bo, clear, dst_mem, dst_st);
 
-               ttm_move_memcpy(bo, dst_mem->num_pages, dst_iter, src_iter);
-       }
-       /* Below dst_mem becomes bo->resource. */
        ttm_bo_move_sync_cleanup(bo, dst_mem);
        i915_ttm_adjust_domains_after_move(obj);
        i915_ttm_free_cached_io_st(obj);