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Diffstat (limited to 'net/packet/af_packet.c')
-rw-r--r--net/packet/af_packet.c66
1 files changed, 60 insertions, 6 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index d5495d87f399..12f2f725a945 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -89,6 +89,7 @@
#include <linux/errqueue.h>
#include <linux/net_tstamp.h>
#include <linux/reciprocal_div.h>
+#include <linux/percpu.h>
#ifdef CONFIG_INET
#include <net/inet_common.h>
#endif
@@ -1168,6 +1169,47 @@ static void packet_increment_head(struct packet_ring_buffer *buff)
buff->head = buff->head != buff->frame_max ? buff->head+1 : 0;
}
+static void packet_inc_pending(struct packet_ring_buffer *rb)
+{
+ this_cpu_inc(*rb->pending_refcnt);
+}
+
+static void packet_dec_pending(struct packet_ring_buffer *rb)
+{
+ this_cpu_dec(*rb->pending_refcnt);
+}
+
+static unsigned int packet_read_pending(const struct packet_ring_buffer *rb)
+{
+ unsigned int refcnt = 0;
+ int cpu;
+
+ /* We don't use pending refcount in rx_ring. */
+ if (rb->pending_refcnt == NULL)
+ return 0;
+
+ for_each_possible_cpu(cpu)
+ refcnt += *per_cpu_ptr(rb->pending_refcnt, cpu);
+
+ return refcnt;
+}
+
+static int packet_alloc_pending(struct packet_sock *po)
+{
+ po->rx_ring.pending_refcnt = NULL;
+
+ po->tx_ring.pending_refcnt = alloc_percpu(unsigned int);
+ if (unlikely(po->tx_ring.pending_refcnt == NULL))
+ return -ENOBUFS;
+
+ return 0;
+}
+
+static void packet_free_pending(struct packet_sock *po)
+{
+ free_percpu(po->tx_ring.pending_refcnt);
+}
+
static bool packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
{
struct sock *sk = &po->sk;
@@ -2014,8 +2056,7 @@ static void tpacket_destruct_skb(struct sk_buff *skb)
__u32 ts;
ph = skb_shinfo(skb)->destructor_arg;
- BUG_ON(atomic_read(&po->tx_ring.pending) == 0);
- atomic_dec(&po->tx_ring.pending);
+ packet_dec_pending(&po->tx_ring);
ts = __packet_set_timestamp(po, ph, skb);
__packet_set_status(po, ph, TP_STATUS_AVAILABLE | ts);
@@ -2236,7 +2277,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
skb_set_queue_mapping(skb, packet_pick_tx_queue(dev));
skb->destructor = tpacket_destruct_skb;
__packet_set_status(po, ph, TP_STATUS_SENDING);
- atomic_inc(&po->tx_ring.pending);
+ packet_inc_pending(&po->tx_ring);
status = TP_STATUS_SEND_REQUEST;
err = po->xmit(skb);
@@ -2256,8 +2297,14 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
}
packet_increment_head(&po->tx_ring);
len_sum += tp_len;
- } while (likely((ph != NULL) || (need_wait &&
- atomic_read(&po->tx_ring.pending))));
+ } while (likely((ph != NULL) ||
+ /* Note: packet_read_pending() might be slow if we have
+ * to call it as it's per_cpu variable, but in fast-path
+ * we already short-circuit the loop with the first
+ * condition, and luckily don't have to go that path
+ * anyway.
+ */
+ (need_wait && packet_read_pending(&po->tx_ring))));
err = len_sum;
goto out_put;
@@ -2556,6 +2603,7 @@ static int packet_release(struct socket *sock)
/* Purge queues */
skb_queue_purge(&sk->sk_receive_queue);
+ packet_free_pending(po);
sk_refcnt_debug_release(sk);
sock_put(sk);
@@ -2717,6 +2765,10 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
po->num = proto;
po->xmit = dev_queue_xmit;
+ err = packet_alloc_pending(po);
+ if (err)
+ goto out2;
+
packet_cached_dev_reset(po);
sk->sk_destruct = packet_sock_destruct;
@@ -2749,6 +2801,8 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
preempt_enable();
return 0;
+out2:
+ sk_free(sk);
out:
return err;
}
@@ -3676,7 +3730,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
if (!closing) {
if (atomic_read(&po->mapped))
goto out;
- if (atomic_read(&rb->pending))
+ if (packet_read_pending(rb))
goto out;
}