Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Vladimir Oltean <vladimir.oltean@nxp.com>
To:     netdev@vger.kernel.org
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Jiri Pirko <jiri@resnulli.us>,
        Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
        Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>,
        Peilin Ye <yepeilin.cs@gmail.com>,
        Pedro Tammela <pctammela@mojatatu.com>,
        Richard Cochran <richardcochran@gmail.com>,
        Zhengchao Shao <shaozhengchao@huawei.com>,
        Maxim Georgiev <glipus@gmail.com>
Subject: [PATCH v2 net-next 1/9] net/sched: taprio: don't access q->qdiscs[] in unoffloaded mode during attach()
Date:   Wed, 14 Jun 2023 00:54:32 +0300
Message-Id: <20230613215440.2465708-2-vladimir.oltean@nxp.com>
In-Reply-To: <20230613215440.2465708-1-vladimir.oltean@nxp.com>
References: <20230613215440.2465708-1-vladimir.oltean@nxp.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?2L/vo6S0ff/1rrwNORA5UEP0tRMkC+sgID88/nstO46gb2HGJ0Me0+daaXnI?=
 =?us-ascii?Q?2g68jM5dADcUwagHUVAazNOh+6927xA4kKHuSWt2tyHndnQ2YfrtovUuv1o7?=
 =?us-ascii?Q?5YoPMjI3Y3hkuz2XzevlD7r5GtAc9uDErtNamwBJIXeSH2dWL58aaRnU2tDj?=
 =?us-ascii?Q?VObbanCqMUeRifUGaejUNSMC4p9jUt8EMVzBOJ040xSbiJ90m6QIbNBF6VHk?=
 =?us-ascii?Q?0udb8119KXi7mEMvt+BumaENyCO1i3BG35918IMwJOIe0bWxzYgYg3ZuQzdJ?=
 =?us-ascii?Q?yaiPuYNckm7enyY3YMAyAP1B7YB5A5M0GuMI7bE9FhbotJs++MG+1HMTa+Y8?=
 =?us-ascii?Q?+dP0YNmOFeKyP9CYvtVGRGXKXhxp+cH09ReDs6CGomhEyd9u3RjS2b5l/bF5?=
 =?us-ascii?Q?WyGKqUAEznvquDvk+YydFNem8UBs9/rhz8ocsi52mWnwoeLTkxJiCY+vFD5f?=
 =?us-ascii?Q?PDboAj/H/36tfCoBA4b0qlZRPtq1klV4CBUEZtAEczDF7oEbBh1rxgtlod2W?=
 =?us-ascii?Q?vVm6+s86LqxUuBJwHbAJ6/27FyKd6KvI9Rr6Xzv1n++UJbmxHfKQIzAhUpxF?=
 =?us-ascii?Q?a60WbsqhzyGKYxceK08O4J2aCt01NXUXRatR9+0JLR5IjQP3CyDqCkMepWE8?=
 =?us-ascii?Q?ZZq4EvNfCwtBWR4Ek5+xAakDzwRnJEPuHDah8uhS8qqs6nnuJ9wCjVsgxwd2?=
 =?us-ascii?Q?5PrTMlSBHu3nMRXv+VTCC0NxoWcgjtRGN92jnQ8kc6FVhm2klgeDL1Pk6Ph3?=
 =?us-ascii?Q?fcX9eAGP2mr83ebZ1vRi8wzZxe0958WWtzGtiaQzU9/n6p2couSKw+QmpCxL?=
 =?us-ascii?Q?QR+TsJ6MntPSKL+cpVTZOJraXtF//VFgtFRvrxoOpRBrAgZdUAWH6ZzvZxGS?=
 =?us-ascii?Q?XkytLYqwCITxLoJEXAKe4vsuUerVCmiPKC8ploVQLXQyyrwE7mgX4AbLPnmm?=
 =?us-ascii?Q?zQllnbf4VQnC7s0q6lFIukT4fcysnx2rxmsKOmxGWu6IUJweVsK8zwdi4ekM?=
 =?us-ascii?Q?yEh2qLzv/jrXDiuipgDVNQfAGlQzQP0vKzZdyM0PdM0W+c4hbVRMtMN+vR7H?=
 =?us-ascii?Q?z748RTz6BV8AW+KndAgrG7GoTyJ70M0bOdxumGrBnhH6dQUXmLntXR80qf7W?=
 =?us-ascii?Q?CdThIZpMbC3fP2uk/yk5MFGhfhMo6q9QMLPJaLqfErKSPAFdCKA1xayJYvWp?=
 =?us-ascii?Q?GPbvzb6PlD1myANGptro4csCziMrqvsVnHCMqCOICl4XCojkuj6DMc7ARXDi?=
 =?us-ascii?Q?s+vAUeksay2zqF/bblv9p50Dxk1IdA4L7oAMnUlhy/PBubHmRBmay/yDqqOu?=
 =?us-ascii?Q?3IDyHhN6NapSYLkIMAS5zq/4NX9cydY7umKky8zKub644Zd9p8mYyR4hAR0L?=
 =?us-ascii?Q?Gd2j074gaqKYMFjdwMXqbQq1SkqE85TtUAJ33UaaSFMj/S7+jIy4TlpYhvEU?=
 =?us-ascii?Q?s8eYusiR8ChWLSvpSrrqLyZLS+OgQiXHkXVH02PO6buXEF9oqHp6Y0bjd9Np?=
 =?us-ascii?Q?YI64kSTW1TefRI/WQwegqSEtJOqsYobB1ExDVUVdOkdJSfvxHj33mSXrhtvw?=
 =?us-ascii?Q?O8z5oR8rmd/b/jSHd3Z/AQIPMMT+B95MIrP6iRYUrv3UfJgyw/mfsB2m/P25?=
 =?us-ascii?Q?Aw=3D=3D?=
X-OriginatorOrg: nxp.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 54e67235-69dc-4355-ba78-08db6c58d0b7
X-MS-Exchange-CrossTenant-AuthSource: AM0PR04MB6452.eurprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 13 Jun 2023 21:54:52.0093
 (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: uQeVilbYZuSLAjXLfah3x5Zy4psHsJSHP2UKvWyqLVF0oTG3ujTdIIKSdn3TqMieM/uyGILqUYo8wL9+QsiACg==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM9PR04MB8081
X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,
        RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_PASS,T_SCC_BODY_TEXT_LINE,
        URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

This is a simple code transformation with no intended behavior change,
just to make it absolutely clear that q->qdiscs[] is only attached to
the child taprio classes in full offload mode.

Right now we use the q->qdiscs[] variable in taprio_attach() for
software mode too, but that is quite confusing and avoidable. We use
it only to reach the netdev TX queue, but we could as well just use
netdev_get_tx_queue() for that.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v1->v2: none

 net/sched/sch_taprio.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index c6627f5abdfa..3ee8a7cca786 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -2131,14 +2131,20 @@ static void taprio_attach(struct Qdisc *sch)
 
 	/* Attach underlying qdisc */
 	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
-		struct Qdisc *qdisc = q->qdiscs[ntx];
+		struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, ntx);
 		struct Qdisc *old;
 
 		if (FULL_OFFLOAD_IS_ENABLED(q->flags)) {
+			struct Qdisc *qdisc = q->qdiscs[ntx];
+
 			qdisc->flags |= TCQ_F_ONETXQUEUE | TCQ_F_NOPARENT;
-			old = dev_graft_qdisc(qdisc->dev_queue, qdisc);
+			old = dev_graft_qdisc(dev_queue, qdisc);
 		} else {
-			old = dev_graft_qdisc(qdisc->dev_queue, sch);
+			/* In software mode, attach the root taprio qdisc
+			 * to all netdev TX queues, so that dev_qdisc_enqueue()
+			 * goes through taprio_enqueue().
+			 */
+			old = dev_graft_qdisc(dev_queue, sch);
 			qdisc_refcount_inc(sch);
 		}
 		if (old)
-- 
2.34.1