Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932122AbbDQJ4v (ORCPT ); Fri, 17 Apr 2015 05:56:51 -0400 Received: from mout.kundenserver.de ([212.227.126.130]:54046 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752627AbbDQJ4s (ORCPT ); Fri, 17 Apr 2015 05:56:48 -0400 From: Arnd Bergmann To: Rameshwar Sahu Cc: linux-arm-kernel@lists.infradead.org, Vinod Koul , dan.j.williams@intel.com, devicetree@vger.kernel.org, jcm@redhat.com, patches@apm.com, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org Subject: Re: [PATCH v3] dmaengine: xgene-dma: Fix sparse wannings and coccinelle warnings Date: Fri, 17 Apr 2015 11:56:38 +0200 Message-ID: <3598557.qxzZhd2MFW@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: References: <1429212673-22254-1-git-send-email-rsahu@apm.com> <2380806.YAnOxsf686@wuerfel> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:x9sZKREnvnKH6mW+Qawq0IpqulKRdx4f2uKlubsV93NJ/ADjYUX RaZpNNdWvojXbtruwAjxITcHQP7Zw+dAKAPeK5Y2szvbUv3SuhwV/F8zg5DV8UGYak/siMS B9Ohww3o2yhePVKjHwAJ0jU8hLUwjjbJ3hvusHZq/vTsGp8VzXfxU4p7Toe+dWfGMn7Tp3O MQ6YvaBV5r56mAghO8Hlw== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2150 Lines: 56 On Friday 17 April 2015 14:41:02 Rameshwar Sahu wrote: > >> > >> -static void *xgene_dma_lookup_ext8(u64 *desc, int idx) > >> +static __le64 *xgene_dma_lookup_ext8(struct xgene_dma_desc_hw *desc, int idx) > >> { > >> - return (idx % 2) ? (desc + idx - 1) : (desc + idx + 1); > >> + switch (idx) { > >> + case 0: > >> + return &desc->m1; > >> + case 1: > >> + return &desc->m0; > >> + case 2: > >> + return &desc->m3; > >> + case 3: > >> + return &desc->m2; > >> + default: > >> + pr_err("Invalid dma descriptor index\n"); > >> + } > >> + > >> + return NULL; > >> } > >> > > ... > > > >> /* Set 1st to 5th source addresses */ > >> for (i = 0; i < src_cnt; i++) { > >> len = *nbytes; > >> - xgene_dma_set_src_buffer((i == 0) ? (desc1 + 8) : > >> + xgene_dma_set_src_buffer((i == 0) ? &desc1->m1 : > >> xgene_dma_lookup_ext8(desc2, i - 1), > >> &len, &src[i]); > >> - XGENE_DMA_DESC_MULTI_SET(desc1, scf[i], i); > >> + desc1->m2 |= cpu_to_le64((scf[i] << ((i + 1) * 8))); > >> } > > > > If you just unroll this loop, you get code that is smaller and easier to > > understand: > > > > /* Set 1st to 5th source addresses */ > > xgene_dma_set_src_buffer(&desc1->m1, &len, &src[0]); > > xgene_dma_set_src_buffer(&desc2->m0, &len, &src[1]); > > xgene_dma_set_src_buffer(&desc2->m3, &len, &src[2]); > > xgene_dma_set_src_buffer(&desc2->m2, &len, &src[3]); > > desc1->m2 |= cpu_to_le64(scf[0] | scf[1] << 8 | scf[2] << 16 | scf[3] << 24); > > Actually here, in run time src_cnt value can be 2 or 3 upto 5, so we > can't unroll it. I see, sorry for misreading the code. The patch is good then as it is. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/