From patchwork Thu Dec 3 14:02:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Zimmermann X-Patchwork-Id: 337297 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FC7EC001B0 for ; Thu, 3 Dec 2020 14:04:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F5D3206D8 for ; Thu, 3 Dec 2020 14:04:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730609AbgLCOEa (ORCPT ); Thu, 3 Dec 2020 09:04:30 -0500 Received: from mx2.suse.de ([195.135.220.15]:35302 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726712AbgLCOE3 (ORCPT ); Thu, 3 Dec 2020 09:04:29 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C2D9BADB3; Thu, 3 Dec 2020 14:03:08 +0000 (UTC) From: Thomas Zimmermann To: airlied@redhat.com, daniel@ffwll.ch, maarten.lankhorst@linux.intel.com, mripard@kernel.org, hdegoede@redhat.com, christian.koenig@amd.com, sumit.semwal@linaro.org Cc: dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, Thomas Zimmermann Subject: [PATCH v2 5/7] drm/vram-helper: Remove vmap reference counting Date: Thu, 3 Dec 2020 15:02:57 +0100 Message-Id: <20201203140259.26580-6-tzimmermann@suse.de> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201203140259.26580-1-tzimmermann@suse.de> References: <20201203140259.26580-1-tzimmermann@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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 --- 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];