From patchwork Tue Apr 17 15:58:14 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Robin Murphy X-Patchwork-Id: 10345523 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 397C660216 for ; Tue, 17 Apr 2018 15:58:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2C78428438 for ; Tue, 17 Apr 2018 15:58:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 20E5328451; Tue, 17 Apr 2018 15:58:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B761728438 for ; Tue, 17 Apr 2018 15:58:27 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 4E22B6E02D; Tue, 17 Apr 2018 15:58:25 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by gabe.freedesktop.org (Postfix) with ESMTP id 17A876E159; Tue, 17 Apr 2018 15:58:22 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0361215AD; Tue, 17 Apr 2018 08:58:22 -0700 (PDT) Received: from e110467-lin.cambridge.arm.com (e110467-lin.cambridge.arm.com [10.1.210.88]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BD89A3F25D; Tue, 17 Apr 2018 08:58:20 -0700 (PDT) From: Robin Murphy To: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH v2 2/3] drm/amdgpu: Allow dma_map_sg() coalescing Date: Tue, 17 Apr 2018 16:58:14 +0100 Message-Id: <622c9ac3784170880dbde6900146e68631df958a.1523977133.git.robin.murphy@arm.com> X-Mailer: git-send-email 2.16.1.dirty In-Reply-To: References: X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: okaya@codeaurora.org, alexander.deucher@amd.com, christian.koenig@amd.com MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP The amdgpu driver doesn't appear to directly use the scatterlist mapped by amdgpu_ttm_tt_pin_userptr(), it merely hands it off to drm_prime_sg_to_page_addr_arrays() to generate the dma_address array which it actually cares about. Now that the latter can cope with dma_map_sg() coalescing dma-contiguous segments such that it returns 0 < count < nents, we can relax the current count == nents check to only consider genuine failure as other drivers do. This avoids a false negative on arm64 systems with an IOMMU. Reported-by: Sinan Kaya Signed-off-by: Robin Murphy Tested-by: Sinan Kaya --- v2: Expand commit message to clarify drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 205da3ff9cd0..f81e96a4242f 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -813,7 +813,7 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm) r = -ENOMEM; nents = dma_map_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents, direction); - if (nents != ttm->sg->nents) + if (nents == 0) goto release_sg; drm_prime_sg_to_page_addr_arrays(ttm->sg, ttm->pages,