[PATCH net-next v2 0/3] sch_netem: some improvements and cleanups.

[PATCH net-next v2 0/3] sch_netem: some improvements and cleanups.

[Yang Yingliang]

v1 -> v2:
	remove patch #4.

 patch 1/3: To avoid breaking old settings when we change failed,
	    do return errcode before doing setup.
 pacth 2/3: Replace some functions' parameters, these functions
	    only need struct netem_sched_data *q.
 patch 3/3: Replace magic numbers with enumerate for better readability.

Yang Yingliang (3):
  sch_netem: return errcode before setting params
  sch_netem: change some func's param from "struct Qdisc *" to "struct
    netem_sched_data *"
  sch_netem: replace magic numbers with enumerate in GE model

 net/sched/sch_netem.c | 75 ++++++++++++++++++++++++++++++++-------------------
 1 file changed, 47 insertions(+), 28 deletions(-)

-- 
1.8.0

[PATCH net-next v2 1/3] sch_netem: return errcode before setting params

[Yang Yingliang]

get_dist_table() and get_loss_clg() may be failed. These
two functions should be called after setting the members
of qdisc_priv(sch), or it will break the old settings while
either of them is failed.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 net/sched/sch_netem.c | 39 +++++++++++++++++++++++++++++----------
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index de1059a..b341943 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -821,6 +821,8 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
 	struct netem_sched_data *q = qdisc_priv(sch);
 	struct nlattr *tb[TCA_NETEM_MAX + 1];
 	struct tc_netem_qopt *qopt;
+	struct clgstate old_clg;
+	int old_loss_model = CLG_RANDOM;
 	int ret;
 
 	if (opt == NULL)
@@ -831,6 +833,33 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
 	if (ret < 0)
 		return ret;
 
+	/* backup q->clg and q->loss_model */
+	old_clg = q->clg;
+	old_loss_model = q->loss_model;
+
+	if (tb[TCA_NETEM_LOSS]) {
+		ret = get_loss_clg(sch, tb[TCA_NETEM_LOSS]);
+		if (ret) {
+			q->loss_model = old_loss_model;
+			return ret;
+		}
+	} else {
+		q->loss_model = CLG_RANDOM;
+	}
+
+	if (tb[TCA_NETEM_DELAY_DIST]) {
+		ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]);
+		if (ret) {
+			/* recover clg and loss_model, in case of
+			 * q->clg and q->loss_model were modified
+			 * in get_loss_clg()
+			 */
+			q->clg = old_clg;
+			q->loss_model = old_loss_model;
+			return ret;
+		}
+	}
+
 	sch->limit = qopt->limit;
 
 	q->latency = qopt->latency;
@@ -850,12 +879,6 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
 	if (tb[TCA_NETEM_CORR])
 		get_correlation(sch, tb[TCA_NETEM_CORR]);
 
-	if (tb[TCA_NETEM_DELAY_DIST]) {
-		ret = get_dist_table(sch, tb[TCA_NETEM_DELAY_DIST]);
-		if (ret)
-			return ret;
-	}
-
 	if (tb[TCA_NETEM_REORDER])
 		get_reorder(sch, tb[TCA_NETEM_REORDER]);
 
@@ -872,10 +895,6 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
 	if (tb[TCA_NETEM_ECN])
 		q->ecn = nla_get_u32(tb[TCA_NETEM_ECN]);
 
-	q->loss_model = CLG_RANDOM;
-	if (tb[TCA_NETEM_LOSS])
-		ret = get_loss_clg(sch, tb[TCA_NETEM_LOSS]);
-
 	return ret;
 }
 
-- 
1.8.0

[PATCH net-next v2 2/3] sch_netem: change some func's param from "struct Qdisc *" to "struct netem_sched_data *"

[Yang Yingliang]

In netem_change(), we have already get "struct netem_sched_data *q".
Replace params of get_correlation() and other similar functions with
"struct netem_sched_data *q".

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 net/sched/sch_netem.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index b341943..4a5eb28 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -689,9 +689,8 @@ static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr)
 	return 0;
 }
 
-static void get_correlation(struct Qdisc *sch, const struct nlattr *attr)
+static void get_correlation(struct netem_sched_data *q, const struct nlattr *attr)
 {
-	struct netem_sched_data *q = qdisc_priv(sch);
 	const struct tc_netem_corr *c = nla_data(attr);
 
 	init_crandom(&q->delay_cor, c->delay_corr);
@@ -699,27 +698,24 @@ static void get_correlation(struct Qdisc *sch, const struct nlattr *attr)
 	init_crandom(&q->dup_cor, c->dup_corr);
 }
 
-static void get_reorder(struct Qdisc *sch, const struct nlattr *attr)
+static void get_reorder(struct netem_sched_data *q, const struct nlattr *attr)
 {
-	struct netem_sched_data *q = qdisc_priv(sch);
 	const struct tc_netem_reorder *r = nla_data(attr);
 
 	q->reorder = r->probability;
 	init_crandom(&q->reorder_cor, r->correlation);
 }
 
-static void get_corrupt(struct Qdisc *sch, const struct nlattr *attr)
+static void get_corrupt(struct netem_sched_data *q, const struct nlattr *attr)
 {
-	struct netem_sched_data *q = qdisc_priv(sch);
 	const struct tc_netem_corrupt *r = nla_data(attr);
 
 	q->corrupt = r->probability;
 	init_crandom(&q->corrupt_cor, r->correlation);
 }
 
-static void get_rate(struct Qdisc *sch, const struct nlattr *attr)
+static void get_rate(struct netem_sched_data *q, const struct nlattr *attr)
 {
-	struct netem_sched_data *q = qdisc_priv(sch);
 	const struct tc_netem_rate *r = nla_data(attr);
 
 	q->rate = r->rate;
@@ -732,9 +728,8 @@ static void get_rate(struct Qdisc *sch, const struct nlattr *attr)
 		q->cell_size_reciprocal = (struct reciprocal_value) { 0 };
 }
 
-static int get_loss_clg(struct Qdisc *sch, const struct nlattr *attr)
+static int get_loss_clg(struct netem_sched_data *q, const struct nlattr *attr)
 {
-	struct netem_sched_data *q = qdisc_priv(sch);
 	const struct nlattr *la;
 	int rem;
 
@@ -838,7 +833,7 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
 	old_loss_model = q->loss_model;
 
 	if (tb[TCA_NETEM_LOSS]) {
-		ret = get_loss_clg(sch, tb[TCA_NETEM_LOSS]);
+		ret = get_loss_clg(q, tb[TCA_NETEM_LOSS]);
 		if (ret) {
 			q->loss_model = old_loss_model;
 			return ret;
@@ -877,16 +872,16 @@ static int netem_change(struct Qdisc *sch, struct nlattr *opt)
 		q->reorder = ~0;
 
 	if (tb[TCA_NETEM_CORR])
-		get_correlation(sch, tb[TCA_NETEM_CORR]);
+		get_correlation(q, tb[TCA_NETEM_CORR]);
 
 	if (tb[TCA_NETEM_REORDER])
-		get_reorder(sch, tb[TCA_NETEM_REORDER]);
+		get_reorder(q, tb[TCA_NETEM_REORDER]);
 
 	if (tb[TCA_NETEM_CORRUPT])
-		get_corrupt(sch, tb[TCA_NETEM_CORRUPT]);
+		get_corrupt(q, tb[TCA_NETEM_CORRUPT]);
 
 	if (tb[TCA_NETEM_RATE])
-		get_rate(sch, tb[TCA_NETEM_RATE]);
+		get_rate(q, tb[TCA_NETEM_RATE]);
 
 	if (tb[TCA_NETEM_RATE64])
 		q->rate = max_t(u64, q->rate,
-- 
1.8.0

[PATCH net-next v2 3/3] sch_netem: replace magic numbers with enumerate in GE model

[Yang Yingliang]

Replace some magic numbers which describe states of GE model
loss generator with enumerate.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 net/sched/sch_netem.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 4a5eb28..4fced67 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -117,6 +117,11 @@ struct netem_sched_data {
 		LOST_IN_BURST_PERIOD,
 	} _4_state_model;
 
+	enum {
+		GOOD_STATE = 1,
+		BAD_STATE,
+	} GE_state_model;
+
 	/* Correlated Loss Generation models */
 	struct clgstate {
 		/* state of the Markov chain */
@@ -272,15 +277,15 @@ static bool loss_gilb_ell(struct netem_sched_data *q)
 	struct clgstate *clg = &q->clg;
 
 	switch (clg->state) {
-	case 1:
+	case GOOD_STATE:
 		if (prandom_u32() < clg->a1)
-			clg->state = 2;
+			clg->state = BAD_STATE;
 		if (prandom_u32() < clg->a4)
 			return true;
 		break;
-	case 2:
+	case BAD_STATE:
 		if (prandom_u32() < clg->a2)
-			clg->state = 1;
+			clg->state = GOOD_STATE;
 		if (prandom_u32() > clg->a3)
 			return true;
 	}
-- 
1.8.0

Re: [PATCH net-next v2 0/3] sch_netem: some improvements and cleanups.

[David Miller]

From: Yang Yingliang <yangyingliang@huawei.com>
Date: Fri, 14 Feb 2014 10:30:40 +0800

> v1 -> v2:
> 	remove patch #4.
> 
>  patch 1/3: To avoid breaking old settings when we change failed,
> 	    do return errcode before doing setup.
>  pacth 2/3: Replace some functions' parameters, these functions
> 	    only need struct netem_sched_data *q.
>  patch 3/3: Replace magic numbers with enumerate for better readability.

Series applied.

Re: [PATCH net-next v2 3/3] sch_netem: replace magic numbers with enumerate in GE model

[Ben Hutchings]

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On Fri, 2014-02-14 at 10:30 +0800, Yang Yingliang wrote:
> Replace some magic numbers which describe states of GE model
> loss generator with enumerate.
[...]

The name GOOD_STATE should also be used in get_loss_clg() where
clgstate::state is initialised.

Ben.

-- 
Ben Hutchings
Any sufficiently advanced bug is indistinguishable from a feature.

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Re: [PATCH net-next v2 3/3] sch_netem: replace magic numbers with enumerate in GE model

[Yang Yingliang]

On 2014/2/16 20:44, Ben Hutchings wrote:
> On Fri, 2014-02-14 at 10:30 +0800, Yang Yingliang wrote:
>> Replace some magic numbers which describe states of GE model
>> loss generator with enumerate.
> [...]
> 
> The name GOOD_STATE should also be used in get_loss_clg() where
> clgstate::state is initialised.
> 
> Ben.
> 
OK, thanks!

Regards,
Yang