From: Eric Dumazet <edumazet@google.com> To: Vladimir Oltean <vladimir.oltean@nxp.com> Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>, 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>, Kurt Kanzenbach <kurt@linutronix.de>, Jacob Keller <jacob.e.keller@intel.com>, Gerhard Engleder <gerhard@engleder-embedded.com>, Jesse Brandeburg <jesse.brandeburg@intel.com>, Tony Nguyen <anthony.l.nguyen@intel.com>, intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 net-next 10/15] net/sched: make stab available before ops->init() call Date: Fri, 10 Feb 2023 16:07:42 +0100 [thread overview] Message-ID: <CANn89iL=Z8TOymdaBJ8WUBh8pXOgp_tKM3KVsQZ05uT3orOj4w@mail.gmail.com> (raw) In-Reply-To: <20230207135440.1482856-11-vladimir.oltean@nxp.com> On Tue, Feb 7, 2023 at 2:55 PM Vladimir Oltean <vladimir.oltean@nxp.com> wrote: > > Some qdiscs like taprio turn out to be actually pretty reliant on a well > configured stab, to not underestimate the skb transmission time (by > properly accounting for L1 overhead). > > In a future change, taprio will need the stab, if configured by the > user, to be available at ops->init() time. It will become even more > important in upcoming work, when the overhead will be used for the > queueMaxSDU calculation that is passed to an offloading driver. > > However, rcu_assign_pointer(sch->stab, stab) is called right after > ops->init(), making it unavailable, and I don't really see a good reason > for that. > > Move it earlier, which nicely seems to simplify the error handling path > as well. Well... if you say so :) > > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> > Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> > If TCA_STAB attribute is malformed, we end up calling ->destroy() on a not yet initialized qdisc :/ I am going to send the following fix, unless someone disagrees. (Moving qdisc_put_stab() _after_ ops->destroy(sch) is not strictly needed for a fix, but undo should be done in reverse steps for clarity. diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index e9780631b5b58202068e20c42ccf1197eac2194c..aba789c30a2eb50d339b8a888495b794825e1775 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1286,7 +1286,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev, stab = qdisc_get_stab(tca[TCA_STAB], extack); if (IS_ERR(stab)) { err = PTR_ERR(stab); - goto err_out4; + goto err_out3; } rcu_assign_pointer(sch->stab, stab); } @@ -1294,14 +1294,14 @@ static struct Qdisc *qdisc_create(struct net_device *dev, if (ops->init) { err = ops->init(sch, tca[TCA_OPTIONS], extack); if (err != 0) - goto err_out5; + goto err_out4; } if (tca[TCA_RATE]) { err = -EOPNOTSUPP; if (sch->flags & TCQ_F_MQROOT) { NL_SET_ERR_MSG(extack, "Cannot attach rate estimator to a multi-queue root qdisc"); - goto err_out5; + goto err_out4; } err = gen_new_estimator(&sch->bstats, @@ -1312,7 +1312,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev, tca[TCA_RATE]); if (err) { NL_SET_ERR_MSG(extack, "Failed to generate new estimator"); - goto err_out5; + goto err_out4; } } @@ -1321,12 +1321,13 @@ static struct Qdisc *qdisc_create(struct net_device *dev, return sch; -err_out5: - qdisc_put_stab(rtnl_dereference(sch->stab)); err_out4: - /* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */ + /* Even if ops->init() failed, we call ops->destroy() + * like qdisc_create_dflt(). + */ if (ops->destroy) ops->destroy(sch); + qdisc_put_stab(rtnl_dereference(sch->stab)); err_out3: netdev_put(dev, &sch->dev_tracker); qdisc_free(sch);
WARNING: multiple messages have this Message-ID (diff)
From: Eric Dumazet <edumazet@google.com> To: Vladimir Oltean <vladimir.oltean@nxp.com> Cc: Jiri Pirko <jiri@resnulli.us>, netdev@vger.kernel.org, Kurt Kanzenbach <kurt@linutronix.de>, Jamal Hadi Salim <jhs@mojatatu.com>, Jesse Brandeburg <jesse.brandeburg@intel.com>, Gerhard Engleder <gerhard@engleder-embedded.com>, Tony Nguyen <anthony.l.nguyen@intel.com>, Jakub Kicinski <kuba@kernel.org>, Cong Wang <xiyou.wangcong@gmail.com>, Paolo Abeni <pabeni@redhat.com>, "David S. Miller" <davem@davemloft.net>, linux-kernel@vger.kernel.org, intel-wired-lan@lists.osuosl.org Subject: Re: [Intel-wired-lan] [PATCH v2 net-next 10/15] net/sched: make stab available before ops->init() call Date: Fri, 10 Feb 2023 16:07:42 +0100 [thread overview] Message-ID: <CANn89iL=Z8TOymdaBJ8WUBh8pXOgp_tKM3KVsQZ05uT3orOj4w@mail.gmail.com> (raw) In-Reply-To: <20230207135440.1482856-11-vladimir.oltean@nxp.com> On Tue, Feb 7, 2023 at 2:55 PM Vladimir Oltean <vladimir.oltean@nxp.com> wrote: > > Some qdiscs like taprio turn out to be actually pretty reliant on a well > configured stab, to not underestimate the skb transmission time (by > properly accounting for L1 overhead). > > In a future change, taprio will need the stab, if configured by the > user, to be available at ops->init() time. It will become even more > important in upcoming work, when the overhead will be used for the > queueMaxSDU calculation that is passed to an offloading driver. > > However, rcu_assign_pointer(sch->stab, stab) is called right after > ops->init(), making it unavailable, and I don't really see a good reason > for that. > > Move it earlier, which nicely seems to simplify the error handling path > as well. Well... if you say so :) > > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> > Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> > If TCA_STAB attribute is malformed, we end up calling ->destroy() on a not yet initialized qdisc :/ I am going to send the following fix, unless someone disagrees. (Moving qdisc_put_stab() _after_ ops->destroy(sch) is not strictly needed for a fix, but undo should be done in reverse steps for clarity. diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index e9780631b5b58202068e20c42ccf1197eac2194c..aba789c30a2eb50d339b8a888495b794825e1775 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1286,7 +1286,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev, stab = qdisc_get_stab(tca[TCA_STAB], extack); if (IS_ERR(stab)) { err = PTR_ERR(stab); - goto err_out4; + goto err_out3; } rcu_assign_pointer(sch->stab, stab); } @@ -1294,14 +1294,14 @@ static struct Qdisc *qdisc_create(struct net_device *dev, if (ops->init) { err = ops->init(sch, tca[TCA_OPTIONS], extack); if (err != 0) - goto err_out5; + goto err_out4; } if (tca[TCA_RATE]) { err = -EOPNOTSUPP; if (sch->flags & TCQ_F_MQROOT) { NL_SET_ERR_MSG(extack, "Cannot attach rate estimator to a multi-queue root qdisc"); - goto err_out5; + goto err_out4; } err = gen_new_estimator(&sch->bstats, @@ -1312,7 +1312,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev, tca[TCA_RATE]); if (err) { NL_SET_ERR_MSG(extack, "Failed to generate new estimator"); - goto err_out5; + goto err_out4; } } @@ -1321,12 +1321,13 @@ static struct Qdisc *qdisc_create(struct net_device *dev, return sch; -err_out5: - qdisc_put_stab(rtnl_dereference(sch->stab)); err_out4: - /* ops->init() failed, we call ->destroy() like qdisc_create_dflt() */ + /* Even if ops->init() failed, we call ops->destroy() + * like qdisc_create_dflt(). + */ if (ops->destroy) ops->destroy(sch); + qdisc_put_stab(rtnl_dereference(sch->stab)); err_out3: netdev_put(dev, &sch->dev_tracker); qdisc_free(sch); _______________________________________________ Intel-wired-lan mailing list Intel-wired-lan@osuosl.org https://lists.osuosl.org/mailman/listinfo/intel-wired-lan
next prev parent reply other threads:[~2023-02-10 15:08 UTC|newest] Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-02-07 13:54 [PATCH v2 net-next 00/15] taprio automatic queueMaxSDU and new TXQ selection procedure Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [PATCH v2 net-next 01/15] net/sched: taprio: delete peek() implementation Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [PATCH v2 net-next 02/15] net/sched: taprio: continue with other TXQs if one dequeue() failed Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [PATCH v2 net-next 03/15] net/sched: taprio: refactor one skb dequeue from TXQ to separate function Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [PATCH v2 net-next 04/15] net/sched: taprio: avoid calling child->ops->dequeue(child) twice Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [PATCH v2 net-next 05/15] net/sched: taprio: give higher priority to higher TCs in software dequeue mode Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] [PATCH v2 net-next 06/15] net/sched: taprio: calculate tc gate durations Vladimir Oltean 2023-02-07 13:54 ` Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] [PATCH v2 net-next 07/15] net/sched: taprio: rename close_time to end_time Vladimir Oltean 2023-02-07 13:54 ` Vladimir Oltean 2023-02-07 13:54 ` [PATCH v2 net-next 08/15] net/sched: taprio: calculate budgets per traffic class Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [PATCH v2 net-next 09/15] net/sched: taprio: calculate guard band against actual TC gate close time Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [PATCH v2 net-next 10/15] net/sched: make stab available before ops->init() call Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-10 15:07 ` Eric Dumazet [this message] 2023-02-10 15:07 ` Eric Dumazet 2023-02-10 15:20 ` Vladimir Oltean 2023-02-10 15:20 ` [Intel-wired-lan] " Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] [PATCH v2 net-next 11/15] net/sched: taprio: warn about missing size table Vladimir Oltean 2023-02-07 13:54 ` Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] [PATCH v2 net-next 12/15] net/sched: keep the max_frm_len information inside struct sched_gate_list Vladimir Oltean 2023-02-07 13:54 ` Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] [PATCH v2 net-next 13/15] net/sched: taprio: automatically calculate queueMaxSDU based on TC gate durations Vladimir Oltean 2023-02-07 13:54 ` Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] [PATCH v2 net-next 14/15] net/sched: taprio: split segmentation logic from qdisc_enqueue() Vladimir Oltean 2023-02-07 13:54 ` Vladimir Oltean 2023-02-07 13:54 ` [Intel-wired-lan] [PATCH v2 net-next 15/15] net/sched: taprio: don't segment unnecessarily Vladimir Oltean 2023-02-07 13:54 ` Vladimir Oltean 2023-02-08 9:50 ` [PATCH v2 net-next 00/15] taprio automatic queueMaxSDU and new TXQ selection procedure patchwork-bot+netdevbpf 2023-02-08 9:50 ` [Intel-wired-lan] " patchwork-bot+netdevbpf
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