linux-kernel - [PATCH 09/17] net sched actions: Convert to use idr_alloc

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Date:   Tue, 28 Nov 2017 13:33:04 -0800
From:   Matthew Wilcox <willy@...radead.org>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Matthew Wilcox <mawilcox@...rosoft.com>,
        Chris Mi <chrism@...lanox.com>, Jiri Pirko <jiri@...lanox.com>,
        "David S . Miller" <davem@...emloft.net>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Eric Biggers <ebiggers@...gle.com>,
        Lai Jiangshan <laijs@...fujitsu.com>,
        Tejun Heo <tj@...nel.org>, Rehas Sachdeva <aquannie@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 09/17] net sched actions: Convert to use idr_alloc_u32

From: Matthew Wilcox <mawilcox@...rosoft.com>

Use the new helper.  Also untangle the error path, and in so doing
noticed that estimator generator failure would lead to us leaking an
ID.  Fix that bug.

Signed-off-by: Matthew Wilcox <mawilcox@...rosoft.com>
---
 net/sched/act_api.c | 60 ++++++++++++++++++++++-------------------------------
 1 file changed, 25 insertions(+), 35 deletions(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index efb90b8a3bf0..156302c110af 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -274,7 +274,6 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 	struct tcf_idrinfo *idrinfo = tn->idrinfo;
 	struct idr *idr = &idrinfo->action_idr;
 	int err = -ENOMEM;
-	unsigned long idr_index;
 
 	if (unlikely(!p))
 		return -ENOMEM;
@@ -284,45 +283,28 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 
 	if (cpustats) {
 		p->cpu_bstats = netdev_alloc_pcpu_stats(struct gnet_stats_basic_cpu);
-		if (!p->cpu_bstats) {
-err1:
-			kfree(p);
-			return err;
-		}
-		p->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
-		if (!p->cpu_qstats) {
-err2:
-			free_percpu(p->cpu_bstats);
+		if (!p->cpu_bstats)
 			goto err1;
-		}
+		p->cpu_qstats = alloc_percpu(struct gnet_stats_queue);
+		if (!p->cpu_qstats)
+			goto err2;
 	}
 	spin_lock_init(&p->tcfa_lock);
+	idr_preload(GFP_KERNEL);
+	spin_lock_bh(&idrinfo->lock);
 	/* user doesn't specify an index */
 	if (!index) {
-		idr_preload(GFP_KERNEL);
-		spin_lock_bh(&idrinfo->lock);
-		err = idr_alloc_ext(idr, NULL, &idr_index, 1, 0,
-				    GFP_ATOMIC);
-		spin_unlock_bh(&idrinfo->lock);
-		idr_preload_end();
-		if (err) {
-err3:
-			free_percpu(p->cpu_qstats);
-			goto err2;
-		}
-		p->tcfa_index = idr_index;
+		index = 1;
+		err = idr_alloc_u32(idr, NULL, &index, UINT_MAX, GFP_ATOMIC);
 	} else {
-		idr_preload(GFP_KERNEL);
-		spin_lock_bh(&idrinfo->lock);
-		err = idr_alloc_ext(idr, NULL, NULL, index, index + 1,
-				    GFP_ATOMIC);
-		spin_unlock_bh(&idrinfo->lock);
-		idr_preload_end();
-		if (err)
-			goto err3;
-		p->tcfa_index = index;
+		err = idr_alloc_u32(idr, NULL, &index, index, GFP_ATOMIC);
 	}
+	spin_unlock_bh(&idrinfo->lock);
+	idr_preload_end();
+	if (err)
+		goto err3;
 
+	p->tcfa_index = index;
 	p->tcfa_tm.install = jiffies;
 	p->tcfa_tm.lastuse = jiffies;
 	p->tcfa_tm.firstuse = 0;
@@ -330,9 +312,8 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 		err = gen_new_estimator(&p->tcfa_bstats, p->cpu_bstats,
 					&p->tcfa_rate_est,
 					&p->tcfa_lock, NULL, est);
-		if (err) {
-			goto err3;
-		}
+		if (err)
+			goto err4;
 	}
 
 	p->idrinfo = idrinfo;
@@ -340,6 +321,15 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, struct nlattr *est,
 	INIT_LIST_HEAD(&p->list);
 	*a = p;
 	return 0;
+err4:
+	idr_remove(idr, index);
+err3:
+	free_percpu(p->cpu_qstats);
+err2:
+	free_percpu(p->cpu_bstats);
+err1:
+	kfree(p);
+	return err;
 }
 EXPORT_SYMBOL(tcf_idr_create);
 
-- 
2.15.0