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dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.117.160 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.117.160; helo=mail.nvidia.com; pr=C Received: from mail.nvidia.com (216.228.117.160) by BN2PEPF000044A4.mail.protection.outlook.com (10.167.243.155) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.25.13 via Frontend Transport; Wed, 13 May 2026 18:53:07 +0000 Received: from rnnvmail201.nvidia.com (10.129.68.8) by mail.nvidia.com (10.129.200.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Wed, 13 May 2026 11:52:37 -0700 Received: from dev.nvidia.com (10.126.230.37) by rnnvmail201.nvidia.com (10.129.68.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Wed, 13 May 2026 11:52:35 -0700 From: Chaitanya Kulkarni To: , , , , , , CC: , , , , Pranjal Shrivastava , Xiao Ni , Chaitanya Kulkarni Subject: [PATCH V4 2/3] md: propagate BLK_FEAT_PCI_P2PDMA from member devices to RAID device Date: Wed, 13 May 2026 11:51:52 -0700 Message-ID: <20260513185153.95552-3-kch@nvidia.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260513185153.95552-1-kch@nvidia.com> References: <20260513185153.95552-1-kch@nvidia.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: rnnvmail201.nvidia.com (10.129.68.8) To rnnvmail201.nvidia.com (10.129.68.8) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BN2PEPF000044A4:EE_|LV3PR12MB9258:EE_ X-MS-Office365-Filtering-Correlation-Id: 74f6b971-47db-406e-66d6-08deb120df27 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|36860700016|1800799024|376014|7416014|82310400026|22082099003|56012099003|18002099003|11063799003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: M+jJyJlDBGsXNlmHfm0iJvr3UFLdk62HMerzAll0JqUtQjrwwmCKb0V0jSUg6oZp/L/5FvygaN9gSTHGpYeunGCXYtAoCEWG+E/LjVPVG0K4aHWsimwI0oqfrArxIJEcAYFcEVXCtmZfnem5oNnz5wQrrPEk/SfNdeuEaP8q3gZmfO1ySirvc6FzFoAXG9q9BRtwLpR67USVLQyqenuvZHhe+VInKPvws4iVHZBohk0hCPKbqFnzyPasWqKnYJvt8zxmNr5NXPp+tOtKrppIce5L/gqZoVHabAm7ai8qs+S1hpTtGQyeAlXSbgB0DXeyOnfIF6K31mfbL9ayv+EVgYsPYmfRPxbtAzqZVpe0OVE8yyQ8ueU68nWX8C4yYOE3vWrIP+I9X+EjrQd/o5b3g/ZCupMWpTEPXVIZMMiaca7zOi6sQf+Fg7gvkyAglqBg X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 May 2026 18:53:07.2290 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 74f6b971-47db-406e-66d6-08deb120df27 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN2PEPF000044A4.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV3PR12MB9258 From: Kiran Kumar Modukuri MD RAID does not propagate BLK_FEAT_PCI_P2PDMA from member devices to the RAID device, preventing peer-to-peer DMA through the RAID layer even when all underlying devices support it. Enable BLK_FEAT_PCI_P2PDMA unconditionally in raid0, raid1 and raid10 personalities during queue limits setup. blk_stack_limits() clears it automatically if any member device lacks support, consistent with how BLK_FEAT_NOWAIT and BLK_FEAT_POLL are handled in the block core. Parity RAID personalities (raid4/5/6) are excluded because they require CPU access to data pages for parity computation, which is incompatible with P2P mappings. Tested with RAID0/1/10 arrays containing multiple NVMe devices with P2PDMA support, confirming that peer-to-peer transfers work correctly through the RAID layer. Tested-by: Pranjal Shrivastava Reviewed-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Reviewed-by: Xiao Ni Signed-off-by: Kiran Kumar Modukuri Signed-off-by: Chaitanya Kulkarni --- drivers/md/raid0.c | 1 + drivers/md/raid1.c | 1 + drivers/md/raid10.c | 1 + 3 files changed, 3 insertions(+) diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index 5e38a51e349a..2cdaf7495d92 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -392,6 +392,7 @@ static int raid0_set_limits(struct mddev *mddev) lim.io_opt = lim.io_min * mddev->raid_disks; lim.chunk_sectors = mddev->chunk_sectors; lim.features |= BLK_FEAT_ATOMIC_WRITES; + lim.features |= BLK_FEAT_PCI_P2PDMA; err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY); if (err) return err; diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 64d970e2ef50..cc628a1be52c 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -3208,6 +3208,7 @@ static int raid1_set_limits(struct mddev *mddev) lim.max_hw_wzeroes_unmap_sectors = 0; lim.logical_block_size = mddev->logical_block_size; lim.features |= BLK_FEAT_ATOMIC_WRITES; + lim.features |= BLK_FEAT_PCI_P2PDMA; err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY); if (err) return err; diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 39085e7dd6d2..f905dc391b74 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -3941,6 +3941,7 @@ static int raid10_set_queue_limits(struct mddev *mddev) lim.chunk_sectors = mddev->chunk_sectors; lim.io_opt = lim.io_min * raid10_nr_stripes(conf); lim.features |= BLK_FEAT_ATOMIC_WRITES; + lim.features |= BLK_FEAT_PCI_P2PDMA; err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY); if (err) return err; -- 2.39.5