drm/i915/ttm: Update i915_gem_obj_copy_ttm() to be asynchronous

Update the copy function i915_gem_obj_copy_ttm() to be asynchronous for
future users and update the only current user to sync the objects
as needed after this function.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211122214554.371864-7-thomas.hellstrom@linux.intel.com

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
index 43423d3..80df9f5 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -826,33 +826,49 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
                .interruptible = intr,
        };
        struct i915_refct_sgt *dst_rsgt;
-       struct dma_fence *copy_fence;
-       int ret;
+       struct dma_fence *copy_fence, *dep_fence;
+       struct i915_deps deps;
+       int ret, shared_err;
 
        assert_object_held(dst);
        assert_object_held(src);
+       i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
 
        /*
-        * Sync for now. This will change with async moves.
+        * We plan to add a shared fence only for the source. If that
+        * fails, we await all source fences before commencing
+        * the copy instead of only the exclusive.
         */
-       ret = ttm_bo_wait_ctx(dst_bo, &ctx);
+       shared_err = dma_resv_reserve_shared(src_bo->base.resv, 1);
+       ret = i915_deps_add_resv(&deps, dst_bo->base.resv, true, false, &ctx);
        if (!ret)
-               ret = ttm_bo_wait_ctx(src_bo, &ctx);
+               ret = i915_deps_add_resv(&deps, src_bo->base.resv,
+                                        !!shared_err, false, &ctx);
        if (ret)
                return ret;
 
+       dep_fence = i915_deps_to_fence(&deps, &ctx);
+       if (IS_ERR(dep_fence))
+               return PTR_ERR(dep_fence);
+
        dst_rsgt = i915_ttm_resource_get_st(dst, dst_bo->resource);
        copy_fence = __i915_ttm_move(src_bo, false, dst_bo->resource,
-                                    dst_bo->ttm, dst_rsgt, allow_accel, NULL);
+                                    dst_bo->ttm, dst_rsgt, allow_accel,
+                                    dep_fence);
 
        i915_refct_sgt_put(dst_rsgt);
-       if (IS_ERR(copy_fence))
-               return PTR_ERR(copy_fence);
+       if (IS_ERR_OR_NULL(copy_fence))
+               return PTR_ERR_OR_ZERO(copy_fence);
 
-       if (copy_fence) {
-               dma_fence_wait(copy_fence, false);
-               dma_fence_put(copy_fence);
-       }
+       dma_resv_add_excl_fence(dst_bo->base.resv, copy_fence);
+
+       /* If we failed to reserve a shared slot, add an exclusive fence */
+       if (shared_err)
+               dma_resv_add_excl_fence(src_bo->base.resv, copy_fence);
+       else
+               dma_resv_add_shared_fence(src_bo->base.resv, copy_fence);
+
+       dma_fence_put(copy_fence);
 
        return 0;
 }

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
index 60d10ab..9aad840 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_pm.c
@@ -80,6 +80,7 @@ static int i915_ttm_backup(struct i915_gem_apply_to_region *apply,
 
        err = i915_gem_obj_copy_ttm(backup, obj, pm_apply->allow_gpu, false);
        GEM_WARN_ON(err);
+       ttm_bo_wait_ctx(backup_bo, &ctx);
 
        obj->ttm.backup = backup;
        return 0;
@@ -170,6 +171,7 @@ static int i915_ttm_restore(struct i915_gem_apply_to_region *apply,
                err = i915_gem_obj_copy_ttm(obj, backup, pm_apply->allow_gpu,
                                            false);
                GEM_WARN_ON(err);
+               ttm_bo_wait_ctx(backup_bo, &ctx);
 
                obj->ttm.backup = NULL;
                err = 0;