From mboxrd@z Thu Jan 1 00:00:00 1970 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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 47C95C4338F for ; Mon, 23 Aug 2021 10:29:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2516E6138B for ; Mon, 23 Aug 2021 10:29:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236157AbhHWKag (ORCPT ); Mon, 23 Aug 2021 06:30:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236186AbhHWKaf (ORCPT ); Mon, 23 Aug 2021 06:30:35 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 294DEC0613C1 for ; Mon, 23 Aug 2021 03:29:52 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id mq2-20020a17090b3802b0290178911d298bso11829322pjb.1 for ; Mon, 23 Aug 2021 03:29:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=TOLTokCzMJhrS4yVrsvWA7I6iBUF0+poQl+b02sEUsU=; b=d9NEFEsJvNYuoSyxsZify90/61cU0ZWsqGqoaLu3c/SUinZZoaJcAChNdiUafs14Nv N3KqQ1KblO+pmVxCokfC7ZdftZMq7xlJGPht149Gw9/q+RpW+bM9wjB87l8ayQVeFADe BFKdmTC2z4eDlJw0XWNRyVZ1bTu3DpAHkrhwg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=TOLTokCzMJhrS4yVrsvWA7I6iBUF0+poQl+b02sEUsU=; b=dqzXoRCqSd3NcFy8VunU+gnRo7vwNOxxla9FCx0kvpfu7vm1rg10WvAxpZUCinaAh2 VwMJwNmpA2ocLz5rbnR/+4jBDTvdLSqfri6YuugpnoQW5qCqhlh63ulw9cPC/4vatesS V4Wyt8t1wBvzN80ceosXV6sSEcN//i201A7YTFJqOTmLgK0slceZu6AsULfNNfaoC5HL 4GsSgBwoyi9sxw1jp57AKX/zBvBZaaWjsTEUJf5ZYn53hn7v3uU5paqifXMq6qgh2UY6 d18XJckbWV0FrltiAjyf+vV6f5H/+Zzr9cVSaxEkgF/XWTeJfBnTv3QOJ2zvduERK1XH cSmw== X-Gm-Message-State: AOAM533OuGIxIg8pWZD4xV1DUZjm18GHIvSMLZEgZNImGsWP/JEOI+15 GmgG6kKxwtzKjFot+O0OeyuQOg== X-Google-Smtp-Source: ABdhPJwinUyVdRudwqM9L+o/iJXQT+DwNhl+fEJx9YyCPD1iQFkfLjFX8pEzBY8SNHQBcPV/LthnDA== X-Received: by 2002:a17:90a:cc8:: with SMTP id 8mr19829798pjt.194.1629714591769; Mon, 23 Aug 2021 03:29:51 -0700 (PDT) Received: from google.com ([2409:10:2e40:5100:8821:8b2f:2912:f9e4]) by smtp.gmail.com with ESMTPSA id z11sm15397918pfn.69.2021.08.23.03.29.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Aug 2021 03:29:51 -0700 (PDT) Date: Mon, 23 Aug 2021 19:29:46 +0900 From: Sergey Senozhatsky To: Hans Verkuil Cc: Sergey Senozhatsky , Tomasz Figa , Dafna Hirschfeld , Ricardo Ribalda , Christoph Hellwig , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCHv4 8/8] videobuf2: handle non-contiguous DMA allocations Message-ID: References: <20210727070517.443167-1-senozhatsky@chromium.org> <20210727070517.443167-9-senozhatsky@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On (21/08/03 12:15), Hans Verkuil wrote: > > static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv) > > { > > struct vb2_dc_buf *buf = buf_priv; > > - struct dma_buf_map map; > > - int ret; > > > > - if (!buf->vaddr && buf->db_attach) { > > - ret = dma_buf_vmap(buf->db_attach->dmabuf, &map); > > - buf->vaddr = ret ? NULL : map.vaddr; > > + if (buf->vaddr) > > + return buf->vaddr; > > + > > + if (buf->db_attach) { > > + struct dma_buf_map map; > > + > > + if (!dma_buf_vmap(buf->db_attach->dmabuf, &map)) > > + buf->vaddr = map.vaddr; > > + > > + return buf->vaddr; > > } > > > > + if (!buf->coherent_mem) > > + buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size, > > + buf->dma_sgt); > > return buf->vaddr; > > } > > This function really needs a bunch of comments. > > What I want to see here specifically is under which circumstances this function > can return NULL. > > - dma_buf_vmap returns an error > - for non-coherent memory dma_vmap_noncontiguous returns an error > - coherent memory with DMA_ATTR_NO_KERNEL_MAPPING set. Done.