From e8462600662621db47bccf8174bf683513aa7102 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Mon, 18 Jan 2021 09:58:07 +0100 Subject: [PATCH] drm/vram-helper: Reuse existing page mappings in vmap 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 Reported-by: Eli Cohen --- 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..a57790b0d985 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 arround. 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, -- 2.29.2