Keep track for which BO a resource was allocated.
This is necessary to move the LRU handling into the resources.
A bit problematic is i915 since it tries to use the resource
interface without a BO which is illegal from the conceptional
point of view.
v2: Document that this is a weak reference and add a workaround for i915
v3: further document that this is protected by ttm_device::lru_lock and
clarify the i915 workaround
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/i915/intel_region_ttm.c | 22 ++++++++++++----------
drivers/gpu/drm/ttm/ttm_bo_util.c | 7 +++++--
drivers/gpu/drm/ttm/ttm_resource.c | 9 +++++++++
include/drm/ttm/ttm_resource.h | 4 ++++
4 files changed, 30 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_region_ttm.c b/drivers/gpu/drm/i915/intel_region_ttm.c
index 27fe0668d094..1b2a61b085f7 100644
--- a/drivers/gpu/drm/i915/intel_region_ttm.c
+++ b/drivers/gpu/drm/i915/intel_region_ttm.c
@@ -75,24 +75,26 @@ intel_region_ttm_node_reserve(struct intel_memory_region *mem,
int ret;
/*
- * Having to use a mock_bo is unfortunate but stems from some
- * drivers having private managers that insist to know what the
- * allocate memory is intended for, using it to send private
- * data to the manager. Also recently the bo has been used to send
- * alignment info to the manager. Assume that apart from the latter,
- * none of the managers we use will ever access the buffer object
- * members, hoping we can pass the alignment info in the
- * struct ttm_place in the future.
+ * This is essential an illegal use the of the TTM resource manager
+ * backend and should be fixed in the future. For now work around by
+ * using a mock_bo with at least the mandatory fields initialized.
+ *
+ * The resource should be ignored by TTM since it can't grab a
+ * reference to the BO during eviction.
*/
place.fpfn = offset >> PAGE_SHIFT;
place.lpfn = place.fpfn + (size >> PAGE_SHIFT);
mock_bo.base.size = size;
+ mock_bo.bdev = &mem->i915->bdev;
ret = man->func->alloc(man, &mock_bo, &place, &res);
if (ret == -ENOSPC)
- ret = -ENXIO;
+ return ERR_PTR(-ENXIO);
+ if (ret)
+ return ERR_PTR(ret);
- return ret ? ERR_PTR(ret) : res;
+ res->bo = NULL;
+ return 0;
}
/**
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 763fa6f4e07d..c5d02edaefc0 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -242,6 +242,11 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
if (bo->type != ttm_bo_type_sg)
fbo->base.base.resv = &fbo->base.base._resv;
+ if (fbo->base.resource) {
+ ttm_resource_set_bo(fbo->base.resource, &fbo->base);
+ bo->resource = NULL;
+ }
+
dma_resv_init(&fbo->base.base._resv);
fbo->base.base.dev = NULL;
ret = dma_resv_trylock(&fbo->base.base._resv);
@@ -510,7 +515,6 @@ static int ttm_bo_move_to_ghost(struct ttm_buffer_object *bo,
ghost_obj->ttm = NULL;
else
bo->ttm = NULL;
- bo->resource = NULL;
dma_resv_unlock(&ghost_obj->base._resv);
ttm_bo_put(ghost_obj);
@@ -638,7 +642,6 @@ int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo)
dma_resv_unlock(&ghost->base._resv);
ttm_bo_put(ghost);
bo->ttm = ttm;
- bo->resource = NULL;
ttm_bo_assign_mem(bo, sys_res);
return 0;
diff --git a/drivers/gpu/drm/ttm/ttm_resource.c b/drivers/gpu/drm/ttm/ttm_resource.c
index 122f19e6968b..a4c495da0040 100644
--- a/drivers/gpu/drm/ttm/ttm_resource.c
+++ b/drivers/gpu/drm/ttm/ttm_resource.c
@@ -41,6 +41,7 @@ void ttm_resource_init(struct ttm_buffer_object *bo,
res->bus.offset = 0;
res->bus.is_iomem = false;
res->bus.caching = ttm_cached;
+ res->bo = bo;
}
EXPORT_SYMBOL(ttm_resource_init);
@@ -73,6 +74,14 @@ void ttm_resource_free(struct ttm_buffer_object *bo, struct ttm_resource **res)
}
EXPORT_SYMBOL(ttm_resource_free);
+void ttm_resource_set_bo(struct ttm_resource *res,
+ struct ttm_buffer_object *bo)
+{
+ spin_lock(&bo->bdev->lru_lock);
+ res->bo = bo;
+ spin_unlock(&bo->bdev->lru_lock);
+}
+
/**
* ttm_resource_manager_init
*
diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h
index c004672789b6..e8080192cae4 100644
--- a/include/drm/ttm/ttm_resource.h
+++ b/include/drm/ttm/ttm_resource.h
@@ -160,6 +160,7 @@ struct ttm_bus_placement {
* @mem_type: Resource type of the allocation.
* @placement: Placement flags.
* @bus: Placement on io bus accessible to the CPU
+ * @bo: weak reference to the BO, protected by ttm_device::lru_lock
*
* Structure indicating the placement and space resources used by a
* buffer object.
@@ -170,6 +171,7 @@ struct ttm_resource {
uint32_t mem_type;
uint32_t placement;
struct ttm_bus_placement bus;
+ struct ttm_buffer_object *bo;
};
/**
@@ -268,6 +270,8 @@ int ttm_resource_alloc(struct ttm_buffer_object *bo,
const struct ttm_place *place,
struct ttm_resource **res);
void ttm_resource_free(struct ttm_buffer_object *bo, struct ttm_resource **res);
+void ttm_resource_set_bo(struct ttm_resource *res,
+ struct ttm_buffer_object *bo);
void ttm_resource_manager_init(struct ttm_resource_manager *man,
struct ttm_device *bdev,
--
2.25.1
