Overlapping or nested mappings of the same BO are not allowed by the semantics of the GEM vmap/vunmap operations. Concurent access to the GEM object is prevented by reservation locks.
So we don't need the reference counter in the GEM VRAM object. Remove it.
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de --- drivers/gpu/drm/drm_gem_vram_helper.c | 19 ++++--------------- include/drm/drm_gem_vram_helper.h | 17 +++-------------- 2 files changed, 7 insertions(+), 29 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c index 760d77c6c3c0..276e8f8ea663 100644 --- a/drivers/gpu/drm/drm_gem_vram_helper.c +++ b/drivers/gpu/drm/drm_gem_vram_helper.c @@ -113,7 +113,6 @@ static void drm_gem_vram_cleanup(struct drm_gem_vram_object *gbo) * up; only release the GEM object. */
- WARN_ON(gbo->vmap_use_count); WARN_ON(dma_buf_map_is_set(&gbo->map));
drm_gem_object_release(&gbo->bo.base); @@ -384,15 +383,10 @@ static int drm_gem_vram_kmap_locked(struct drm_gem_vram_object *gbo, { int ret;
- if (gbo->vmap_use_count > 0) - goto out; - ret = ttm_bo_vmap(&gbo->bo, &gbo->map); if (ret) return ret;
-out: - ++gbo->vmap_use_count; *map = gbo->map;
return 0; @@ -403,15 +397,9 @@ static void drm_gem_vram_kunmap_locked(struct drm_gem_vram_object *gbo, { struct drm_device *dev = gbo->bo.base.dev;
- if (drm_WARN_ON_ONCE(dev, !gbo->vmap_use_count)) - return; - if (drm_WARN_ON_ONCE(dev, !dma_buf_map_is_equal(&gbo->map, map))) return; /* BUG: map not mapped from this BO */
- if (--gbo->vmap_use_count > 0) - return; - /* * Permanently mapping and unmapping buffers adds overhead from * updating the page tables and creates debugging output. Therefore, @@ -545,12 +533,13 @@ static void drm_gem_vram_bo_driver_move_notify(struct drm_gem_vram_object *gbo, struct ttm_resource *new_mem) { struct ttm_buffer_object *bo = &gbo->bo; - struct drm_device *dev = bo->base.dev; + struct dma_buf_map *map = &gbo->map;
- if (drm_WARN_ON_ONCE(dev, gbo->vmap_use_count)) + if (dma_buf_map_is_null(map)) return;
- ttm_bo_vunmap(bo, &gbo->map); + ttm_bo_vunmap(bo, map); + dma_buf_map_clear(map); }
static int drm_gem_vram_bo_driver_move(struct drm_gem_vram_object *gbo, diff --git a/include/drm/drm_gem_vram_helper.h b/include/drm/drm_gem_vram_helper.h index a4bac02249c2..48af238b5ca9 100644 --- a/include/drm/drm_gem_vram_helper.h +++ b/include/drm/drm_gem_vram_helper.h @@ -41,25 +41,14 @@ struct vm_area_struct; * dedicated memory. The buffer object can be evicted to system memory if * video memory becomes scarce. * - * GEM VRAM objects perform reference counting for pin and mapping - * operations. So a buffer object that has been pinned N times with - * drm_gem_vram_pin() must be unpinned N times with - * drm_gem_vram_unpin(). The same applies to pairs of - * drm_gem_vram_kmap() and drm_gem_vram_kunmap(), as well as pairs of - * drm_gem_vram_vmap() and drm_gem_vram_vunmap(). + * GEM VRAM objects perform reference counting for pin operations. So a + * buffer object that has been pinned N times with drm_gem_vram_pin() must + * be unpinned N times with drm_gem_vram_unpin(). */ struct drm_gem_vram_object { struct ttm_buffer_object bo; struct dma_buf_map map;
- /** - * @vmap_use_count: - * - * Reference count on the virtual address. - * The address are un-mapped when the count reaches zero. - */ - unsigned int vmap_use_count; - /* Supported placements are %TTM_PL_VRAM and %TTM_PL_SYSTEM */ struct ttm_placement placement; struct ttm_place placements[2];