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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 5F7B5C4363A for ; Mon, 26 Oct 2020 23:50:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1887221655 for ; Mon, 26 Oct 2020 23:50:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603756259; bh=j8+aveAqrJQEVzbm2fQkpi44naYHrixzixT0DdUmo5A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=z6NxKVaERYU6GG4Gqu4ygNDsIcN2qNAPPLnECwJlKMelrsaKPQcQS0BT19a5ouJs9 Rx2Eso0h8wEtkm3Zb0Wdh7TE1bFo4zVBHjVDFe7ffr0HS0ieSlMCkstvtJ4gUQXwI3 VntSO9Ml1RNgqtpLHcCAazE/80fY4xbrVa888Ksw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2409243AbgJZXu5 (ORCPT ); Mon, 26 Oct 2020 19:50:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:49734 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2409103AbgJZXuX (ORCPT ); Mon, 26 Oct 2020 19:50:23 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 16B1B2075B; Mon, 26 Oct 2020 23:50:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603756222; bh=j8+aveAqrJQEVzbm2fQkpi44naYHrixzixT0DdUmo5A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uhJHajN05XdyKQNP3gZpGIRZiFVOsNjDBVOIJHE6npc+ADEGGTWD4twcXlr//Gzw+ 63SpAPUMffktbH4QiOwm90Tizcrla1eYVBT7x1XbQcoWH3bWSmu1JLCuDZarx7Gqrr P4ToM9QncBvJWQbimTSHHt60lvgcP6vyoqa1XUMM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Marek Szyprowski , Juergen Gross , Sasha Levin , xen-devel@lists.xenproject.org Subject: [PATCH AUTOSEL 5.9 062/147] xen: gntdev: fix common struct sg_table related issues Date: Mon, 26 Oct 2020 19:47:40 -0400 Message-Id: <20201026234905.1022767-62-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201026234905.1022767-1-sashal@kernel.org> References: <20201026234905.1022767-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marek Szyprowski [ Upstream commit d1749eb1ab85e04e58c29e58900e3abebbdd6e82 ] The Documentation/DMA-API-HOWTO.txt states that the dma_map_sg() function returns the number of the created entries in the DMA address space. However the subsequent calls to the dma_sync_sg_for_{device,cpu}() and dma_unmap_sg must be called with the original number of the entries passed to the dma_map_sg(). struct sg_table is a common structure used for describing a non-contiguous memory buffer, used commonly in the DRM and graphics subsystems. It consists of a scatterlist with memory pages and DMA addresses (sgl entry), as well as the number of scatterlist entries: CPU pages (orig_nents entry) and DMA mapped pages (nents entry). It turned out that it was a common mistake to misuse nents and orig_nents entries, calling DMA-mapping functions with a wrong number of entries or ignoring the number of mapped entries returned by the dma_map_sg() function. To avoid such issues, lets use a common dma-mapping wrappers operating directly on the struct sg_table objects and use scatterlist page iterators where possible. This, almost always, hides references to the nents and orig_nents entries, making the code robust, easier to follow and copy/paste safe. Signed-off-by: Marek Szyprowski Acked-by: Juergen Gross Signed-off-by: Sasha Levin --- drivers/xen/gntdev-dmabuf.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c index b1b6eebafd5de..4c13cbc99896a 100644 --- a/drivers/xen/gntdev-dmabuf.c +++ b/drivers/xen/gntdev-dmabuf.c @@ -247,10 +247,9 @@ static void dmabuf_exp_ops_detach(struct dma_buf *dma_buf, if (sgt) { if (gntdev_dmabuf_attach->dir != DMA_NONE) - dma_unmap_sg_attrs(attach->dev, sgt->sgl, - sgt->nents, - gntdev_dmabuf_attach->dir, - DMA_ATTR_SKIP_CPU_SYNC); + dma_unmap_sgtable(attach->dev, sgt, + gntdev_dmabuf_attach->dir, + DMA_ATTR_SKIP_CPU_SYNC); sg_free_table(sgt); } @@ -288,8 +287,8 @@ dmabuf_exp_ops_map_dma_buf(struct dma_buf_attachment *attach, sgt = dmabuf_pages_to_sgt(gntdev_dmabuf->pages, gntdev_dmabuf->nr_pages); if (!IS_ERR(sgt)) { - if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir, - DMA_ATTR_SKIP_CPU_SYNC)) { + if (dma_map_sgtable(attach->dev, sgt, dir, + DMA_ATTR_SKIP_CPU_SYNC)) { sg_free_table(sgt); kfree(sgt); sgt = ERR_PTR(-ENOMEM); @@ -633,7 +632,7 @@ dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev, /* Now convert sgt to array of pages and check for page validity. */ i = 0; - for_each_sg_page(sgt->sgl, &sg_iter, sgt->nents, 0) { + for_each_sgtable_page(sgt, &sg_iter, 0) { struct page *page = sg_page_iter_page(&sg_iter); /* * Check if page is valid: this can happen if we are given -- 2.25.1