Commit 791a3e9f authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net/packet: convert po->pressure to an atomic flag 



Not only this removes some READ_ONCE()/WRITE_ONCE(),
this also removes one integer.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 61edf479

net/packet/af_packet.c

+8 −6
Original line number Diff line number Diff line
@@ -1307,22 +1307,23 @@ static int __packet_rcv_has_room(const struct packet_sock *po, 


static int packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)

{

	int pressure, ret;

	bool pressure;

	int ret;



	ret = __packet_rcv_has_room(po, skb);

	pressure = ret != ROOM_NORMAL;



	if (READ_ONCE(po->pressure) != pressure)

		WRITE_ONCE(po->pressure, pressure);

	if (packet_sock_flag(po, PACKET_SOCK_PRESSURE) != pressure)

		packet_sock_flag_set(po, PACKET_SOCK_PRESSURE, pressure);



	return ret;

}



static void packet_rcv_try_clear_pressure(struct packet_sock *po)

{

	if (READ_ONCE(po->pressure) &&

	if (packet_sock_flag(po, PACKET_SOCK_PRESSURE) &&

	    __packet_rcv_has_room(po, NULL) == ROOM_NORMAL)

		WRITE_ONCE(po->pressure,  0);

		packet_sock_flag_set(po, PACKET_SOCK_PRESSURE, false);

}



static void packet_sock_destruct(struct sock *sk)
@@ -1409,7 +1410,8 @@ static unsigned int fanout_demux_rollover(struct packet_fanout *f, 
	i = j = min_t(int, po->rollover->sock, num - 1);

	do {

		po_next = pkt_sk(rcu_dereference(f->arr[i]));

		if (po_next != po_skip && !READ_ONCE(po_next->pressure) &&

		if (po_next != po_skip &&

		    !packet_sock_flag(po_next, PACKET_SOCK_PRESSURE) &&

		    packet_rcv_has_room(po_next, skb) == ROOM_NORMAL) {

			if (i != j)

				po->rollover->sock = i;

net/packet/internal.h

+1 −1
Original line number Diff line number Diff line
@@ -117,7 +117,6 @@ struct packet_sock { 
	spinlock_t		bind_lock;

	struct mutex		pg_vec_lock;

	unsigned long		flags;

	int			pressure;

	int			ifindex;	/* bound device		*/

	__be16			num;

	struct packet_rollover	*rollover;
@@ -146,6 +145,7 @@ enum packet_sock_flags { 
	PACKET_SOCK_TP_LOSS,

	PACKET_SOCK_HAS_VNET_HDR,

	PACKET_SOCK_RUNNING,

	PACKET_SOCK_PRESSURE,

};



static inline void packet_sock_flag_set(struct packet_sock *po,