Commit 1ef5789d authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

macvlan: annotate data-races around port->bc_queue_len_used 



port->bc_queue_len_used is read and written locklessly,
add READ_ONCE()/WRITE_ONCE() annotations.

While WRITE_ONCE() in macvlan_fill_info() is not yet needed,
it is a prereq for future RTNL avoidance.

Fixes: d4bff72c ("macvlan: Support for high multicast packet rate")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260401103809.3038139-2-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f35340f2

drivers/net/macvlan.c

+5 −3
Original line number Diff line number Diff line
@@ -356,6 +356,7 @@ static void macvlan_broadcast_enqueue(struct macvlan_port *port, 
				      const struct macvlan_dev *src,

				      struct sk_buff *skb)

{

	u32 bc_queue_len_used = READ_ONCE(port->bc_queue_len_used);

	struct sk_buff *nskb;

	int err = -ENOMEM;
@@ -366,7 +367,7 @@ static void macvlan_broadcast_enqueue(struct macvlan_port *port, 
	MACVLAN_SKB_CB(nskb)->src = src;



	spin_lock(&port->bc_queue.lock);

	if (skb_queue_len(&port->bc_queue) < port->bc_queue_len_used) {

	if (skb_queue_len(&port->bc_queue) < bc_queue_len_used) {

		if (src)

			dev_hold(src->dev);

		__skb_queue_tail(&port->bc_queue, nskb);
@@ -1731,7 +1732,8 @@ static int macvlan_fill_info(struct sk_buff *skb, 
	}

	if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN, vlan->bc_queue_len_req))

		goto nla_put_failure;

	if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN_USED, port->bc_queue_len_used))

	if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN_USED,

			READ_ONCE(port->bc_queue_len_used)))

		goto nla_put_failure;

	if (port->bc_cutoff != 1 &&

	    nla_put_s32(skb, IFLA_MACVLAN_BC_CUTOFF, port->bc_cutoff))
@@ -1791,7 +1793,7 @@ static void update_port_bc_queue_len(struct macvlan_port *port) 
		if (vlan->bc_queue_len_req > max_bc_queue_len_req)

			max_bc_queue_len_req = vlan->bc_queue_len_req;

	}

	port->bc_queue_len_used = max_bc_queue_len_req;

	WRITE_ONCE(port->bc_queue_len_used, max_bc_queue_len_req);

}



static int macvlan_device_event(struct notifier_block *unused,