From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from MRWPR03CU001.outbound.protection.outlook.com (mail-francesouthazon11011007.outbound.protection.outlook.com [40.107.130.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 606502F1FC7; Fri, 10 Jul 2026 15:22:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.130.7 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783696936; cv=fail; b=rI06g8J8qqfGaabqluDobf009FrxMXHyu+DOBrIH1PeYhlT46fQmG+oK7fpsJQhUm8A7pi7SwlLLv9ppcJlmw1sPgEXaTUgy4DIJV07hMLbnsezhdI7eww9BPXjzswgiQ0oKcyxmrbhbspFaIQHwl4ZgXmQMrDXE2am34wkyUJI= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783696936; c=relaxed/simple; bh=sDavUdrSfMJTseT8aL00Tm+l89izW7JpvvLtLomiZPA=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=q0HtqduE6fcC+Wr9fB1EsBhWvIVa0gvhB4IfKdoTU2Uo9EULT6s3reBVjBBhXqsT85xclmFtyURzywT6bHgwG1xgcMazhCxcjKqvrJ1tvxwUXpqA5Aywbhj/y3l/oGZXCr4+i6NJhIlA05KYyCCLUK4j2NnCTBXcl7yhnStUtb0= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=oss.nxp.com; spf=pass smtp.mailfrom=oss.nxp.com; dkim=fail (2048-bit key) header.d=NXP1.onmicrosoft.com header.i=@NXP1.onmicrosoft.com header.b=jp+cbW4S reason="signature verification failed"; arc=fail smtp.client-ip=40.107.130.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=oss.nxp.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.nxp.com Authentication-Results: smtp.subspace.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=NXP1.onmicrosoft.com header.i=@NXP1.onmicrosoft.com header.b="jp+cbW4S" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=FGh3dfF3CcKTQyU4Ttdd1FJsi6mecWpkka9jARHipfNaw7BrUzzs/ABQDHVhi5xdUlI64eIxfkUej8rrIl1mMgKXwpp8kKpqsnbyfn1P78P/MP1Zt03QA80KogMqfPEIM+5B3BJlLcoe8QoGq3Ik8zq5SXXg2Zl2mgObCuFcVf2H0dps3Uwe++D8kiixwO0+ZIitrKZB4l84J2Yvbgp8QXhtPW96vhT101Rj4d0xkrSs+4mNjC3l2otj8yk82a99u+sO7Jamvcnva7YumaX77BC+9toIzeaCFEelzlHGFucjsNg8INRveH1GLIIn59HVIpom5f5WWsobG1ET+6IbwQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=K7J6NAzQ1KbGL3WPcLaxVG+d+cxmpMxYJNQ8ryd1JUI=; b=KYRx6Yyz34Wvo6hkmX3LEJyzf4Vv9PFY0OwRUKZm+hDKcFGwjOzI88ejmbeOaDYbJrhzQDfw0Y6k/oCQxv4DtehNcLGdOkazft9b9xRbJzJ4amahT76Kx0NQRYYQCsDHQ6uPqQLfgvo3gHtbDs5y1SUx65MlDSmuf8C0cTTU6XGDAxqJIX8a2DZHWT4eV26ShXt5GWLgmId7bdPveUihDcIakLt/Hz0Dr6PDKrtjUUKoS71ojuxTzXPBJXYARe9lxM0LUdOlZjH88qAJlI+J2MbRHCzRYflzw4hFBU4WV2R/NyB0U05oOJAZC/36eRCFMQZEFl8MvA4z/P22SuZsNw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oss.nxp.com; dmarc=pass action=none header.from=oss.nxp.com; dkim=pass header.d=oss.nxp.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=NXP1.onmicrosoft.com; s=selector1-NXP1-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=K7J6NAzQ1KbGL3WPcLaxVG+d+cxmpMxYJNQ8ryd1JUI=; b=jp+cbW4SbYSh5Jy+ExXyfc3I7QA60+xRcVW0Zb2k+Gfn3WTU2/xnVvkxlE5AUVLZH3tDLfteTXL3PUUU6uNaEyxlKxmlbNA+4CGFy7/zj+/kgDEsPqCvF5Wf4/ypGJVgm/y8x6Wth/aF5nB2ZgD8G5iZajo6goYxpsJGQ8Xaf65wiD7KG1mgds6ppQYnOv3xbQL7qmWX2xbFfIWwIqLn6fTANDbqdvSSHS3NPPsPnS+24RoMFmrtGNCY3/39iV0akfQIySrNeInyEsYB2+dpPbHP0W6iV4PThHGSap2rhBrFQTacl5vSXbZJIswkpwfDtsacgSZRx+bYgcNDZIbokg== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=oss.nxp.com; Received: from GV2PR04MB11799.eurprd04.prod.outlook.com (2603:10a6:150:2cf::9) by PA4PR04MB7789.eurprd04.prod.outlook.com (2603:10a6:102:c3::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.181.17; Fri, 10 Jul 2026 15:22:12 +0000 Received: from GV2PR04MB11799.eurprd04.prod.outlook.com ([fe80::2146:83a2:5329:b7c]) by GV2PR04MB11799.eurprd04.prod.outlook.com ([fe80::2146:83a2:5329:b7c%6]) with mapi id 15.21.0159.007; Fri, 10 Jul 2026 15:22:12 +0000 Date: Fri, 10 Jul 2026 10:22:04 -0500 From: Frank Li To: sashiko-reviews@lists.linux.dev Cc: =?iso-8859-1?Q?Beno=EEt?= Monin , Frank.Li@kernel.org, vkoul@kernel.org, dmaengine@vger.kernel.org, imx@lists.linux.dev Subject: Re: [PATCH v6 2/2] dmaengine: fsl-edma: Support dynamic scatter/gather chaining Message-ID: References: <20260710-fsl-edma-dyn-sg-v6-0-831b96be3f31@bootlin.com> <20260710-fsl-edma-dyn-sg-v6-2-831b96be3f31@bootlin.com> <20260710122206.E38231F00A3A@smtp.kernel.org> Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260710122206.E38231F00A3A@smtp.kernel.org> X-ClientProxiedBy: PH8PR07CA0008.namprd07.prod.outlook.com (2603:10b6:510:2cd::16) To GV2PR04MB11799.eurprd04.prod.outlook.com (2603:10a6:150:2cf::9) Precedence: bulk X-Mailing-List: imx@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: GV2PR04MB11799:EE_|PA4PR04MB7789:EE_ X-MS-Office365-Filtering-Correlation-Id: 18e2fa82-582a-43c9-6579-08dede9703bf X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|19092799006|1800799024|366016|376014|23010399003|11063799006|56012099006|4143699003|6133799003|18002099003|22082099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:GV2PR04MB11799.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(19092799006)(1800799024)(366016)(376014)(23010399003)(11063799006)(56012099006)(4143699003)(6133799003)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?iso-8859-1?Q?yy8VtNjS0eDPzpbu3WBA5aRnitY+Hvvxx0bbFvfOoaQ2tiy4RCk+KtsfUJ?= =?iso-8859-1?Q?GAH3dY6Dn+Q4pw+fwxX4Fn/gRN7+pEBOXhykw6/vBoUNvaoHoELdxpsH75?= =?iso-8859-1?Q?N3gPfBDzbpbB3T88TZpMXNsBDyKN2QMYxjI3f9nkSG0l4K1kpdbJmF59ae?= =?iso-8859-1?Q?kCqq12Pbqr7LXs+gJZLDRsFOehqVXLQ02et1BNHH8XD0r2j+rY1Y+PirLC?= =?iso-8859-1?Q?w72waAMdqIby78gUDqhivcP2fLO/G/TP2AlqbLmpvT2k2ZTqB4LaDUB9/k?= =?iso-8859-1?Q?ZKvfg8f0+GIHBvkDqif0nNFXbV+MaKU31+1T3qLtiLduN6OHWBy40Glt62?= =?iso-8859-1?Q?uP5VUml4TWuqSVAdDeSxYZOHuZW7zN+VKBgHBmg71TlJzcXsltzr3ygcnK?= =?iso-8859-1?Q?YX/HudmoU5Dubda/tNjDO7xa34Cs/Akic/Ilxfii09X7Un5Njdrn/jayQu?= =?iso-8859-1?Q?bPqj5/win6jQuV4EzYZ/f63OZUxMtBNPKpwU2cZAYqBAVUpxv8ICl4eAdW?= =?iso-8859-1?Q?mvk8cFJjTq9ZdoUCHy9EZcZPubnMLn2RDvEp5+QYqLYSHbcR8AcWB/VE1e?= =?iso-8859-1?Q?k02yiPynSPX5W7U+obQTBOUrcAg4h0VwKpw1aaxo5kt7rm+2VVHyfdx3uk?= =?iso-8859-1?Q?4dmGZaFKjGAL+L7Wmz/nX+Uu8jaPGv1ENtWHKwe07Zc8VOv1fFJmyyY/GK?= =?iso-8859-1?Q?gi8cFVH2tUMYl9OIsH0HNK4bn4EY7uV6vzB+7c/0TK/1ZNDjiKnE24AxZe?= =?iso-8859-1?Q?jKqMg2LAj6JychPilpW2UfrNIy95MNZ00z0wwwAdPh6VOjy4zRM2TEb8UW?= =?iso-8859-1?Q?GPoIo1wBgjsvW2STYp1Bdv6Kt5DjIiapTkzb8RcfIKrOb5WCvZvPOyp7d9?= =?iso-8859-1?Q?9zr3SdIOUIG/uy8i70PeMtiRI5350D8oZlGEqgq2rZ6yaSBah5KnY5Im1Q?= =?iso-8859-1?Q?Wta9SYdO2LzJCgeEirD4Z/4ZtVFcX74FKFwdbk0eUD1MUYWe4yJD3iq3JN?= =?iso-8859-1?Q?jdETCCeun5yde+iBZP5/6r9bwa+e5xh5wQh7zazqkghLdgkgPNvWsq3Yfk?= =?iso-8859-1?Q?E9GfVZGEDDjlbxOHLK7fRuDkscW3kIW5dmrL432EGeKTXozJaYyE9wwCHZ?= =?iso-8859-1?Q?GoOxD2e3JwDfWVVnirbTTrS282zbMrvahTiNVSuPCN3YyatnL8QBOnBY5e?= =?iso-8859-1?Q?srFOMDaSoMxrALcgKdSOhIfxHtuj2+ALU0dindKPffnYNF5UchRN0ql+qp?= =?iso-8859-1?Q?6RAfKJoT2NhXY1PrO5CE42e4cMe5wGDWm9Di32/agB7L9f1/HWwCTDBjGL?= =?iso-8859-1?Q?UZniMuyuk20CD1Y1Ei4DC+UpANlPWInCGRFcD9hJ1TIwI2aLAHJ6kK5A24?= =?iso-8859-1?Q?N8GiK4F5NVLq1DCGlLAwsq3DlKScAcFEn5CNE17vhOD+p5wo3whZ7ntIlD?= =?iso-8859-1?Q?v7esPUGBobz24qsVNqpTKVocCp9vtyULA2jbq67Ys5MtlvzwKDMlEEgNzk?= =?iso-8859-1?Q?17qByiasVWFysMcYtiKvVfGL8hZA8GI1ipKyTasNz0xnfSjxcZ+OpquXnb?= =?iso-8859-1?Q?rG+TjzyxWr5ht6OsXJYCsHqDaQ5r8vR2xukRcGCsdqFODIeBq44Pl9ot+i?= =?iso-8859-1?Q?l8IhEhBNplBUScSYcy9YFQDS9ivZD/u8w5SKS1euah8PtUfWMmM7iun+Kb?= =?iso-8859-1?Q?x6stzlIlPJxC4mT+Rh1sXjHScv0YKwinsK24D2Ms2EgUDgVxgZlGjEdEQO?= =?iso-8859-1?Q?XNll1YEvDPL7+EDpHnpx4OXnmLVjCJeGPR7ghr5T0EFPSh0i5d+J1WbVzT?= =?iso-8859-1?Q?MXCgFUir+H8lFGGvOfVv/mQqGFV+TP7O/nYScHjZmwHm+U8PygvG?= X-OriginatorOrg: oss.nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 18e2fa82-582a-43c9-6579-08dede9703bf X-MS-Exchange-CrossTenant-AuthSource: GV2PR04MB11799.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Jul 2026 15:22:12.1290 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: nw5/cN4o9SmUL9UofBGp5vzJuT1QJ/cIZLfCMN8N8s6GpJuHCjFhz674wedG1yZQcn1BvbaqyYtcqZml5zPlWVWsmrMy9YK1Q3sWpDVm4iB0aPFUpK4/JmdQOmtVz0TC X-MS-Exchange-Transport-CrossTenantHeadersStamped: PA4PR04MB7789 On Fri, Jul 10, 2026 at 12:22:06PM +0000, sashiko-bot@kernel.org wrote: > Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider: > - [Critical] Dynamically linked descriptors are incorrectly re-executed if the hardware completes the entire scatter/gather chain before the interrupt handler runs. > - [Critical] Dynamic scatter/gather chaining loses the `link_sg_id` on multi-TCD descriptors, causing the interrupt handler to incorrectly reap actively executing descriptors. > -- Overall is good, please check above sashiko report issues Frank > > --- Patch [2]: [PATCH v6 2/2] dmaengine: fsl-edma: Support dynamic scatter/gather chaining --- > commit 7b2e56fb9781985df561a9463fc3de1f384eab25 > Author: Benoît Monin > > dmaengine: fsl-edma: Support dynamic scatter/gather chaining > > Implement dynamic linking of scatter/gather transfers to enable > chaining multiple DMA descriptors without stopping the channel. > This avoids waiting for the channel to go idle if there is another > transaction already issued. > > > diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c > > index c10190164926a..6cca5dca8d60a 100644 > > --- a/drivers/dma/fsl-edma-common.c > > +++ b/drivers/dma/fsl-edma-common.c > > @@ -58,11 +61,29 @@ void fsl_edma_tx_chan_handler(struct fsl_edma_chan *fsl_chan) > > list_del(&fsl_chan->edesc->vdesc.node); > > vchan_cookie_complete(&fsl_chan->edesc->vdesc); > > fsl_chan->edesc = NULL; > > - fsl_chan->status = DMA_COMPLETE; > > + if (!(fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_SPLIT_REG) || > > + (edma_readl_chreg(fsl_chan, ch_csr) & EDMA_V3_CH_CSR_DONE)) { > > + fsl_chan->status = DMA_COMPLETE; > > + } > > } else { > > vchan_cyclic_callback(&fsl_chan->edesc->vdesc); > > } > > > > + if (!fsl_chan->edesc && fsl_chan->status != DMA_COMPLETE) { > > [Severity: Critical] > If the hardware completes the entire scatter/gather chain before the interrupt > handler runs, fsl_chan->status will be set to DMA_COMPLETE above. > > Does this condition then cause the handler to entirely skip reaping the > completed intermediate descriptors? > > > + u8 link_sg_id = FIELD_GET(EDMA_TCD_CSR_LINKCH, edma_read_tcdreg(fsl_chan, csr)); > > + struct virt_dma_desc *vdesc, *tmp; > > + > > + list_for_each_entry_safe(vdesc, tmp, &fsl_chan->vchan.desc_issued, node) { > > + struct fsl_edma_desc *fsl_desc = to_fsl_edma_desc(vdesc); > > + > > + if (link_sg_id == fsl_desc->link_sg_id) > > + break; > > + > > + list_del(&vdesc->node); > > + vchan_cookie_complete(vdesc); > > + } > > + } > > + > > if (!fsl_chan->edesc) > > fsl_edma_xfer_desc(fsl_chan); > > [Severity: Critical] > If the intermediate descriptors are not reaped because fsl_chan->status is > DMA_COMPLETE, will fsl_edma_xfer_desc() pop those already-finished descriptors > from the desc_issued list and re-submit them, causing duplicate I/O execution? > > [ ... ] > > > @@ -924,14 +945,74 @@ void fsl_edma_xfer_desc(struct fsl_edma_chan *fsl_chan) > [ ... ] > > +static void fsl_edma_link_sg(struct fsl_edma_chan *fsl_chan, struct fsl_edma_desc *fsl_desc) > > +{ > [ ... ] > > + first_csr |= FIELD_PREP(EDMA_TCD_CSR_LINKCH, fsl_chan->link_sg_id++); > > + fsl_edma_set_tcd_to_le(fsl_chan, first_tcd, first_csr, csr); > > + fsl_desc->link_sg_id = FIELD_GET(EDMA_TCD_CSR_LINKCH, first_csr); > > [Severity: Critical] > This embedded link_sg_id appears to only be set on the first TCD of the > descriptor. > > If fsl_desc has multiple TCDs, when the hardware progresses to the second TCD, > will it load a link_sg_id of 0? > > If an interrupt fires while the second TCD is active, would > fsl_edma_tx_chan_handler() read the hardware CSR as 0 and mistakenly reap the > actively executing descriptor since it won't match fsl_desc->link_sg_id? > > -- > Sashiko AI review · https://sashiko.dev/#/patchset/20260710-fsl-edma-dyn-sg-v6-0-831b96be3f31@bootlin.com?part=2