From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752532AbbKBUac (ORCPT ); Mon, 2 Nov 2015 15:30:32 -0500 Received: from mout.kundenserver.de ([212.227.126.187]:53101 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751280AbbKBUa3 (ORCPT ); Mon, 2 Nov 2015 15:30:29 -0500 From: Arnd Bergmann To: John Garry Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, linux-scsi@vger.kernel.org, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, JBottomley@odin.com, john.garry2@mail.dcu.ie, linux-kernel@vger.kernel.org, linuxarm@huawei.com, robh+dt@kernel.org, hare@suse.de, galak@codeaurora.org, zhangfei.gao@linaro.org Subject: Re: [PATCH v2 27/32] scsi: hisi_sas: add smp protocol support Date: Mon, 02 Nov 2015 21:29:50 +0100 Message-ID: <4452058.YIXj3BxT1F@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <5637977E.7000704@huawei.com> References: <1445868903-183817-1-git-send-email-john.garry@huawei.com> <5633995D.20607@huawei.com> <5637977E.7000704@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:6GAT9bTm9qcQLTPhKPi24qOt3bH7azfgAoB/5dk+JLoM7zbh7Sv 2V2zKvqEX1g20TGWS5490B5OAcm1Lhmh+ZaJnrIGPUp4hu7t80rNTus3nFeJhtkFsd38LiR pfMmHEbOJyUBp9La451Ucwfmmbv3wqjuQZQ2VAfFLOlRN9VyIWFuirPYxPoCgoI470o47NY 0HgMfHuF1jQ/lPGXA9MzQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:PtWidZrokNA=:1RwSXcAwccF4M7f8FF2ixD zOW3mPkNPUYpdGR3HDc/4QLmPnWTNBGxlh071jaJxr2r+uUvKsfCTxySQ71Ur0Gduck632O5e D0dkTOvE7k9r7v1+HLQoGGrRYtRI64hzqaBpcTxXjZz7MZA7xvMu22EufFA19STR3Q8nybTy3 BbTgr+u6EyItF/Wy/knCSnCVifFX61XPBV+AWLWNZAz8BuOifzGEib3FJw09Mi4dXH2NUnsTi 9pR9YxALAZcxa+pZ4Fo8Y+a80dELVDq/P/93MC4jqSGz3Wv3Ox6QFTEuPw2eZSryCuvJ8rY/j A6l9nmgYTawEziD9koo/EkHhachmrHCKOl1vpK/QtfmvljCcOq/arQ+oGhRVmwt75636nUgId L1BADR/keoNRQiukHNbMvcrMlhd7E+pgVZoYBUIA5LS5eeEZqKGcDK4zNRe1qERlFo8+uGqQU 8JK5oZGHguxF40TSY2e/h/4JdlxVWK6B6S2rBz81h2uj0T7xV9Nm3De5yeU/mXRs9F19jm+0F 6vj53eyoqfODsm8l+XZd4wjGMHyw450MHDEtCET47tSg+7Ka6Uv2gEA2UxmxKtmdHs0WroFS3 FgW2x/+6aAURcZmcPuc/LhCu+LuyJbnQD4byGJ/qubteiCY0VekZPFnJ5eAyQJS3L2oWLmTIA eAA4TWbeT19LnZrubWHTIIv+PQUmds/xkS0ZdRw94MZBQ/xUPVF141mvRyBTvcmwxneiPZzk2 i4dPgbYS30ewDlDz Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 02 November 2015 17:03:58 John Garry wrote: > > > > Can do. Actually sg_req seems only ever has one element: > > expander.c, smp_execute_task() > > sg_init_one(&task->smp_task.smp_req, req, req_size); > > > > > I tried replacing with dma_map_single, but I feel the code is not as > clean as I need to manually set sg_dma_len() and sg_dma_address(): > req_len = sg_dma_len(sg_req) = sg_req->length; > sg_dma_address(sg_req) = dma_map_single(dev, sg_virt(sg_req), > req_len, DMA_TO_DEVICE); > if (dma_mapping_error(dev, sg_dma_address(sg_req))) > return -ENOMEM; > sg_dma_address(sg_req) is used in another function for unmap. > > opinion? > What I meant was not using a struct scatterlist at all: replace the 'sg_req' variable with a normal pointer, and then do hdr->cmd_table_addr = cpu_to_le64(dma_map_single(dev, req, len, DMA_TO_DEVICE)); Any reason this won't work? Arnd