From nobody Tue Apr 7 03:50:46 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94873ECAAD1 for ; Wed, 31 Aug 2022 15:42:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231768AbiHaPmI (ORCPT ); Wed, 31 Aug 2022 11:42:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229812AbiHaPlS (ORCPT ); Wed, 31 Aug 2022 11:41:18 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A663E9F8D2; Wed, 31 Aug 2022 08:40:32 -0700 (PDT) Received: from dimapc.. (109-252-119-13.nat.spd-mgts.ru [109.252.119.13]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by madras.collabora.co.uk (Postfix) with ESMTPSA id CF7886601E0F; Wed, 31 Aug 2022 16:40:01 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1661960404; bh=lqmbMZlr5dkrGqFSyrWeGCXHf4B0xmxBPMBh938KoCw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EAuy4nLlfDO9TVsH5HROK6LfHSaGDAbTbN/zRIX/deEuscp5PL6GdcG1ocb0FhmQq vm/tCnYg7II5mjyvCT2fAryNdNnYPLx1YGmva96OnxCv9p2AcQMgO7a2Ry//qij6YL OCAZmhx5VYy84KsWpiKh8pJK1Lx8enKGiM/CXGR2y6Sz/asIZccaqfjaY+To/VXUBy wnuOMp2zUhytPXc3JIXdgDouOr2haYbmHySGJZOtv6kt5/EbRzbKMJSLesOYtyQl0G PMk8yBLSlC+d9CVKa/v4OlzyQG5H1mlA/NRtsILc5FyvrEewXzVmiTT5t/GforGdo9 Z/3zW6DvacAtw== From: Dmitry Osipenko To: David Airlie , Gerd Hoffmann , Gurchetan Singh , Chia-I Wu , Daniel Vetter , Daniel Almeida , Gert Wollny , Gustavo Padovan , Daniel Stone , Tomeu Vizoso , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Clark , Sumit Semwal , =?UTF-8?q?Christian=20K=C3=B6nig?= , "Pan, Xinhui" , Thierry Reding , Tomasz Figa , Marek Szyprowski , Mauro Carvalho Chehab , Alex Deucher , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Qiang Yu , Srinivas Kandagatla , Amol Maheshwari , Jason Gunthorpe , Leon Romanovsky , Juergen Gross , Stefano Stabellini , Oleksandr Tyshchenko , Tomi Valkeinen , Russell King , Lucas Stach , Christian Gmeiner Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dmitry Osipenko , linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kernel@collabora.com, virtualization@lists.linux-foundation.org, linux-rdma@vger.kernel.org, linux-arm-msm@vger.kernel.org Subject: [PATCH v4 16/21] dma-buf: Move dma_buf_attach() to dynamic locking specification Date: Wed, 31 Aug 2022 18:37:52 +0300 Message-Id: <20220831153757.97381-17-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220831153757.97381-1-dmitry.osipenko@collabora.com> References: <20220831153757.97381-1-dmitry.osipenko@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Move dma-buf attachment API functions to the dynamic locking specification by taking the reservation lock around the mapping operations. The strict locking convention prevents deadlock situations for dma-buf importers and exporters. Signed-off-by: Dmitry Osipenko Reviewed-by: Christian K=C3=B6nig --- drivers/dma-buf/dma-buf.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index ceea4839c641..073942bf5ae9 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -858,8 +858,8 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct d= evice *dev, dma_buf_is_dynamic(dmabuf)) { struct sg_table *sgt; =20 + dma_resv_lock(attach->dmabuf->resv, NULL); if (dma_buf_is_dynamic(attach->dmabuf)) { - dma_resv_lock(attach->dmabuf->resv, NULL); ret =3D dmabuf->ops->pin(attach); if (ret) goto err_unlock; @@ -872,8 +872,7 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct d= evice *dev, ret =3D PTR_ERR(sgt); goto err_unpin; } - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_unlock(attach->dmabuf->resv); + dma_resv_unlock(attach->dmabuf->resv); attach->sgt =3D sgt; attach->dir =3D DMA_BIDIRECTIONAL; } @@ -889,8 +888,7 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct d= evice *dev, dmabuf->ops->unpin(attach); =20 err_unlock: - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_unlock(attach->dmabuf->resv); + dma_resv_unlock(attach->dmabuf->resv); =20 dma_buf_detach(dmabuf, attach); return ERR_PTR(ret); @@ -936,21 +934,19 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dm= a_buf_attachment *attach) if (WARN_ON(!dmabuf || !attach)) return; =20 + dma_resv_lock(attach->dmabuf->resv, NULL); + if (attach->sgt) { - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_lock(attach->dmabuf->resv, NULL); =20 __unmap_dma_buf(attach, attach->sgt, attach->dir); =20 - if (dma_buf_is_dynamic(attach->dmabuf)) { + if (dma_buf_is_dynamic(attach->dmabuf)) dmabuf->ops->unpin(attach); - dma_resv_unlock(attach->dmabuf->resv); - } } - - dma_resv_lock(dmabuf->resv, NULL); list_del(&attach->node); + dma_resv_unlock(dmabuf->resv); + if (dmabuf->ops->detach) dmabuf->ops->detach(dmabuf, attach); =20 --=20 2.37.2