From 5d5a179d3e90a8385b115e4bd19826ea0bcc6d11 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Mon, 1 Apr 2019 15:26:33 -0700 Subject: [PATCH] drm: Add helpers for setting up an array of dma_fence dependencies. I needed to add implicit dependency support for v3d, and Rob Herring has been working on it for panfrost, and I had recently looked at the lima implementation so I think this will be a good intersection of what we all want and simplify our scheduler implementations. v2: Rebase on xa_limit_32b API change, and tiny checkpatch cleanups on the way in (unsigned int vs unsigned, extra return before EXPORT_SYMBOL_GPL) Signed-off-by: Eric Anholt Link: https://patchwork.freedesktop.org/patch/msgid/20190401222635.25013-6-eric@anholt.net Reviewed-and-tested-by: Qiang Yu (v1) --- drivers/gpu/drm/drm_gem.c | 93 +++++++++++++++++++++++++++++++++++++++ include/drm/drm_gem.h | 5 +++ 2 files changed, 98 insertions(+) diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index e93043b64c2d..fae4676707b6 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -1367,3 +1367,96 @@ drm_gem_unlock_reservations(struct drm_gem_object **objs, int count, ww_acquire_fini(acquire_ctx); } EXPORT_SYMBOL(drm_gem_unlock_reservations); + +/** + * drm_gem_fence_array_add - Adds the fence to an array of fences to be + * waited on, deduplicating fences from the same context. + * + * @fence_array array of dma_fence * for the job to block on. + * @fence the dma_fence to add to the list of dependencies. + * + * Returns: + * 0 on success, or an error on failing to expand the array. + */ +int drm_gem_fence_array_add(struct xarray *fence_array, + struct dma_fence *fence) +{ + struct dma_fence *entry; + unsigned long index; + u32 id = 0; + int ret; + + if (!fence) + return 0; + + /* Deduplicate if we already depend on a fence from the same context. + * This lets the size of the array of deps scale with the number of + * engines involved, rather than the number of BOs. + */ + xa_for_each(fence_array, index, entry) { + if (entry->context != fence->context) + continue; + + if (dma_fence_is_later(fence, entry)) { + dma_fence_put(entry); + xa_store(fence_array, index, fence, GFP_KERNEL); + } else { + dma_fence_put(fence); + } + return 0; + } + + ret = xa_alloc(fence_array, &id, fence, xa_limit_32b, GFP_KERNEL); + if (ret != 0) + dma_fence_put(fence); + + return ret; +} +EXPORT_SYMBOL(drm_gem_fence_array_add); + +/** + * drm_gem_fence_array_add_implicit - Adds the implicit dependencies tracked + * in the GEM object's reservation object to an array of dma_fences for use in + * scheduling a rendering job. + * + * This should be called after drm_gem_lock_reservations() on your array of + * GEM objects used in the job but before updating the reservations with your + * own fences. + * + * @fence_array array of dma_fence * for the job to block on. + * @obj the gem object to add new dependencies from. + * @write whether the job might write the object (so we need to depend on + * shared fences in the reservation object). + */ +int drm_gem_fence_array_add_implicit(struct xarray *fence_array, + struct drm_gem_object *obj, + bool write) +{ + int ret; + struct dma_fence **fences; + unsigned int i, fence_count; + + if (!write) { + struct dma_fence *fence = + reservation_object_get_excl_rcu(obj->resv); + + return drm_gem_fence_array_add(fence_array, fence); + } + + ret = reservation_object_get_fences_rcu(obj->resv, NULL, + &fence_count, &fences); + if (ret || !fence_count) + return ret; + + for (i = 0; i < fence_count; i++) { + ret = drm_gem_fence_array_add(fence_array, fences[i]); + if (ret) + break; + } + + for (; i < fence_count; i++) + dma_fence_put(fences[i]); + kfree(fences); + return ret; +} +EXPORT_SYMBOL(drm_gem_fence_array_add_implicit); diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h index 5ee85c9eaa9d..5047c7ee25f5 100644 --- a/include/drm/drm_gem.h +++ b/include/drm/drm_gem.h @@ -390,6 +390,11 @@ int drm_gem_lock_reservations(struct drm_gem_object **objs, int count, struct ww_acquire_ctx *acquire_ctx); void drm_gem_unlock_reservations(struct drm_gem_object **objs, int count, struct ww_acquire_ctx *acquire_ctx); +int drm_gem_fence_array_add(struct xarray *fence_array, + struct dma_fence *fence); +int drm_gem_fence_array_add_implicit(struct xarray *fence_array, + struct drm_gem_object *obj, + bool write); int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev, u32 handle, u64 *offset); int drm_gem_dumb_destroy(struct drm_file *file, -- 2.45.2