From abbc4d6ecd07fa246fd597b5d8fced28f0bcc606 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Mon, 18 Jan 2021 15:46:39 +0100 Subject: [PATCH] drm/vram-helper: Reuse existing page mappings in vmap MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For performance, BO page mappings can stay in place even if the map counter has returned to 0. In these cases, the existing page mapping has to be reused by the next vmap operation. Otherwise a new mapping would be installed and the old mapping's pages leak. Fix the issue by reusing existing page mappings for vmap operations. Signed-off-by: Thomas Zimmermann Fixes: 1086db71a1db ("drm/vram-helper: Remove invariant parameters from internal kmap function") Acked-by: Christian König Tested-by: Eli Cohen Reported-by: Eli Cohen Reported-by: kernel test robot Cc: Daniel Vetter Cc: Christian König Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Link: https://patchwork.freedesktop.org/patch/msgid/20210118144639.27307-1-tzimmermann@suse.de --- drivers/gpu/drm/drm_gem_vram_helper.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c index 02ca22e90290..0b232a73c1b7 100644 --- a/drivers/gpu/drm/drm_gem_vram_helper.c +++ b/drivers/gpu/drm/drm_gem_vram_helper.c @@ -387,9 +387,16 @@ static int drm_gem_vram_kmap_locked(struct drm_gem_vram_object *gbo, if (gbo->vmap_use_count > 0) goto out; - ret = ttm_bo_vmap(&gbo->bo, &gbo->map); - if (ret) - return ret; + /* + * VRAM helpers unmap the BO only on demand. So the previous + * page mapping might still be around. Only vmap if the there's + * no mapping present. + */ + if (dma_buf_map_is_null(&gbo->map)) { + ret = ttm_bo_vmap(&gbo->bo, &gbo->map); + if (ret) + return ret; + } out: ++gbo->vmap_use_count; @@ -577,6 +584,7 @@ static void drm_gem_vram_bo_driver_move_notify(struct drm_gem_vram_object *gbo, return; ttm_bo_vunmap(bo, &gbo->map); + dma_buf_map_clear(&gbo->map); /* explicitly clear mapping for next vmap call */ } static int drm_gem_vram_bo_driver_move(struct drm_gem_vram_object *gbo,