[PATCH net-next 0/2] can: raw: random optimizations

[PATCH net-next 0/2] can: raw: random optimizations

[Ziyang Xuan]

Do some small optimizations for can_raw.

Ziyang Xuan (2):
  can: raw: process optimization in raw_init()
  can: raw: use guard clause to optimize nesting in raw_rcv()

 net/can/raw.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

-- 
2.25.1

[PATCH net-next 1/2] can: raw: process optimization in raw_init()

[Ziyang Xuan]

Now, register notifier after register proto successfully. It can create
raw socket and set socket options once register proto successfully, so it
is possible missing notifier event before register notifier successfully
although this is a low probability scenario.

Move notifier registration to the front of proto registration like done
in j1939. In addition, register_netdevice_notifier() may fail, check its
result is necessary.

Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
---
 net/can/raw.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/net/can/raw.c b/net/can/raw.c
index d1bd9cc51ebe..9ae7c4206b9a 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -942,12 +942,20 @@ static __init int raw_module_init(void)
 
 	pr_info("can: raw protocol\n");
 
+	err = register_netdevice_notifier(&canraw_notifier);
+	if (err)
+		return err;
+
 	err = can_proto_register(&raw_can_proto);
-	if (err < 0)
+	if (err < 0) {
 		pr_err("can: registration of raw protocol failed\n");
-	else
-		register_netdevice_notifier(&canraw_notifier);
+		goto register_proto_failed;
+	}
 
+	return 0;
+
+register_proto_failed:
+	unregister_netdevice_notifier(&canraw_notifier);
 	return err;
 }
 
-- 
2.25.1

[PATCH net-next 2/2] can: raw: use guard clause to optimize nesting in raw_rcv()

[Ziyang Xuan]

We can use guard clause to optimize nesting codes like
if (condition) { ... } else { return; } in raw_rcv();

Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
---
 net/can/raw.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/net/can/raw.c b/net/can/raw.c
index 9ae7c4206b9a..e7dfa3584e29 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -136,14 +136,13 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
 	/* eliminate multiple filter matches for the same skb */
 	if (this_cpu_ptr(ro->uniq)->skb == oskb &&
 	    this_cpu_ptr(ro->uniq)->skbcnt == can_skb_prv(oskb)->skbcnt) {
-		if (ro->join_filters) {
-			this_cpu_inc(ro->uniq->join_rx_count);
-			/* drop frame until all enabled filters matched */
-			if (this_cpu_ptr(ro->uniq)->join_rx_count < ro->count)
-				return;
-		} else {
+		if (!ro->join_filters)
+			return;
+
+		this_cpu_inc(ro->uniq->join_rx_count);
+		/* drop frame until all enabled filters matched */
+		if (this_cpu_ptr(ro->uniq)->join_rx_count < ro->count)
 			return;
-		}
 	} else {
 		this_cpu_ptr(ro->uniq)->skb = oskb;
 		this_cpu_ptr(ro->uniq)->skbcnt = can_skb_prv(oskb)->skbcnt;
-- 
2.25.1

Re: [PATCH net-next 0/2] can: raw: random optimizations

[Marc Kleine-Budde]

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On 27.08.2022 15:20:09, Ziyang Xuan wrote:
> Do some small optimizations for can_raw.

Applied to linux-can-next.

Thanks,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
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