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: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index ec44645..7b9367b 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -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;

diff --git a/net/packet/internal.h b/net/packet/internal.h
index 58f042c..680703d 100644 (file)
--- a/net/packet/internal.h
+++ b/net/packet/internal.h
@@ -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,