1 files changed, 144 insertions, 29 deletions

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index b5989c6ee551..fd5164139bf0 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1234,27 +1234,81 @@ 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)
+#define ROOM_POW_OFF	2
+#define ROOM_NONE	0x0
+#define ROOM_LOW	0x1
+#define ROOM_NORMAL	0x2
+
+static bool __tpacket_has_room(struct packet_sock *po, int pow_off)
+{
+	int idx, len;
+
+	len = po->rx_ring.frame_max + 1;
+	idx = po->rx_ring.head;
+	if (pow_off)
+		idx += len >> pow_off;
+	if (idx >= len)
+		idx -= len;
+	return packet_lookup_frame(po, &po->rx_ring, idx, TP_STATUS_KERNEL);
+}
+
+static bool __tpacket_v3_has_room(struct packet_sock *po, int pow_off)
+{
+	int idx, len;
+
+	len = po->rx_ring.prb_bdqc.knum_blocks;
+	idx = po->rx_ring.prb_bdqc.kactive_blk_num;
+	if (pow_off)
+		idx += len >> pow_off;
+	if (idx >= len)
+		idx -= len;
+	return prb_lookup_block(po, &po->rx_ring, idx, TP_STATUS_KERNEL);
+}
+
+static int __packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
 {
 	struct sock *sk = &po->sk;
-	bool has_room;
+	int ret = ROOM_NONE;
+
+	if (po->prot_hook.func != tpacket_rcv) {
+		int avail = sk->sk_rcvbuf - atomic_read(&sk->sk_rmem_alloc)
+					  - (skb ? skb->truesize : 0);
+		if (avail > (sk->sk_rcvbuf >> ROOM_POW_OFF))
+			return ROOM_NORMAL;
+		else if (avail > 0)
+			return ROOM_LOW;
+		else
+			return ROOM_NONE;
+	}
+
+	if (po->tp_version == TPACKET_V3) {
+		if (__tpacket_v3_has_room(po, ROOM_POW_OFF))
+			ret = ROOM_NORMAL;
+		else if (__tpacket_v3_has_room(po, 0))
+			ret = ROOM_LOW;
+	} else {
+		if (__tpacket_has_room(po, ROOM_POW_OFF))
+			ret = ROOM_NORMAL;
+		else if (__tpacket_has_room(po, 0))
+			ret = ROOM_LOW;
+	}
 
-	if (po->prot_hook.func != tpacket_rcv)
-		return (atomic_read(&sk->sk_rmem_alloc) + skb->truesize)
-			<= sk->sk_rcvbuf;
+	return ret;
+}
 
-	spin_lock(&sk->sk_receive_queue.lock);
-	if (po->tp_version == TPACKET_V3)
-		has_room = prb_lookup_block(po, &po->rx_ring,
-					    po->rx_ring.prb_bdqc.kactive_blk_num,
-					    TP_STATUS_KERNEL);
-	else
-		has_room = packet_lookup_frame(po, &po->rx_ring,
-					       po->rx_ring.head,
-					       TP_STATUS_KERNEL);
-	spin_unlock(&sk->sk_receive_queue.lock);
+static int packet_rcv_has_room(struct packet_sock *po, struct sk_buff *skb)
+{
+	int ret;
+	bool has_room;
+
+	spin_lock_bh(&po->sk.sk_receive_queue.lock);
+	ret = __packet_rcv_has_room(po, skb);
+	has_room = ret == ROOM_NORMAL;
+	if (po->pressure == has_room)
+		po->pressure = !has_room;
+	spin_unlock_bh(&po->sk.sk_receive_queue.lock);
 
-	return has_room;
+	return ret;
 }
 
 static void packet_sock_destruct(struct sock *sk)
@@ -1282,6 +1336,20 @@ static int fanout_rr_next(struct packet_fanout *f, unsigned int num)
 	return x;
 }
 
+static bool fanout_flow_is_huge(struct packet_sock *po, struct sk_buff *skb)
+{
+	u32 rxhash;
+	int i, count = 0;
+
+	rxhash = skb_get_hash(skb);
+	for (i = 0; i < ROLLOVER_HLEN; i++)
+		if (po->rollover->history[i] == rxhash)
+			count++;
+
+	po->rollover->history[prandom_u32() % ROLLOVER_HLEN] = rxhash;
+	return count > (ROLLOVER_HLEN >> 1);
+}
+
 static unsigned int fanout_demux_hash(struct packet_fanout *f,
 				      struct sk_buff *skb,
 				      unsigned int num)
@@ -1318,22 +1386,40 @@ static unsigned int fanout_demux_rnd(struct packet_fanout *f,
 
 static unsigned int fanout_demux_rollover(struct packet_fanout *f,
 					  struct sk_buff *skb,
-					  unsigned int idx, unsigned int skip,
+					  unsigned int idx, bool try_self,
 					  unsigned int num)
 {
-	unsigned int i, j;
+	struct packet_sock *po, *po_next, *po_skip = NULL;
+	unsigned int i, j, room = ROOM_NONE;
 
-	i = j = min_t(int, f->next[idx], num - 1);
+	po = pkt_sk(f->arr[idx]);
+
+	if (try_self) {
+		room = packet_rcv_has_room(po, skb);
+		if (room == ROOM_NORMAL ||
+		    (room == ROOM_LOW && !fanout_flow_is_huge(po, skb)))
+			return idx;
+		po_skip = po;
+	}
+
+	i = j = min_t(int, po->rollover->sock, num - 1);
 	do {
-		if (i != skip && packet_rcv_has_room(pkt_sk(f->arr[i]), skb)) {
+		po_next = pkt_sk(f->arr[i]);
+		if (po_next != po_skip && !po_next->pressure &&
+		    packet_rcv_has_room(po_next, skb) == ROOM_NORMAL) {
 			if (i != j)
-				f->next[idx] = i;
+				po->rollover->sock = i;
+			atomic_long_inc(&po->rollover->num);
+			if (room == ROOM_LOW)
+				atomic_long_inc(&po->rollover->num_huge);
 			return i;
 		}
+
 		if (++i == num)
 			i = 0;
 	} while (i != j);
 
+	atomic_long_inc(&po->rollover->num_failed);
 	return idx;
 }
 
@@ -1386,17 +1472,14 @@ static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
 		idx = fanout_demux_qm(f, skb, num);
 		break;
 	case PACKET_FANOUT_ROLLOVER:
-		idx = fanout_demux_rollover(f, skb, 0, (unsigned int) -1, num);
+		idx = fanout_demux_rollover(f, skb, 0, false, num);
 		break;
 	}
 
-	po = pkt_sk(f->arr[idx]);
-	if (fanout_has_flag(f, PACKET_FANOUT_FLAG_ROLLOVER) &&
-	    unlikely(!packet_rcv_has_room(po, skb))) {
-		idx = fanout_demux_rollover(f, skb, idx, idx, num);
-		po = pkt_sk(f->arr[idx]);
-	}
+	if (fanout_has_flag(f, PACKET_FANOUT_FLAG_ROLLOVER))
+		idx = fanout_demux_rollover(f, skb, idx, true, num);
 
+	po = pkt_sk(f->arr[idx]);
 	return po->prot_hook.func(skb, dev, &po->prot_hook, orig_dev);
 }
 
@@ -1467,6 +1550,16 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
 	if (po->fanout)
 		return -EALREADY;
 
+	if (type == PACKET_FANOUT_ROLLOVER ||
+	    (type_flags & PACKET_FANOUT_FLAG_ROLLOVER)) {
+		po->rollover = kzalloc(sizeof(*po->rollover), GFP_KERNEL);
+		if (!po->rollover)
+			return -ENOMEM;
+		atomic_long_set(&po->rollover->num, 0);
+		atomic_long_set(&po->rollover->num_huge, 0);
+		atomic_long_set(&po->rollover->num_failed, 0);
+	}
+
 	mutex_lock(&fanout_mutex);
 	match = NULL;
 	list_for_each_entry(f, &fanout_list, list) {
@@ -1515,6 +1608,10 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
 	}
 out:
 	mutex_unlock(&fanout_mutex);
+	if (err) {
+		kfree(po->rollover);
+		po->rollover = NULL;
+	}
 	return err;
 }
 
@@ -1536,6 +1633,8 @@ static void fanout_release(struct sock *sk)
 		kfree(f);
 	}
 	mutex_unlock(&fanout_mutex);
+
+	kfree(po->rollover);
 }
 
 static const struct proto_ops packet_ops;
@@ -2835,7 +2934,7 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
 	sock->state = SS_UNCONNECTED;
 
 	err = -ENOBUFS;
-	sk = sk_alloc(net, PF_PACKET, GFP_KERNEL, &packet_proto);
+	sk = sk_alloc(net, PF_PACKET, GFP_KERNEL, &packet_proto, kern);
 	if (sk == NULL)
 		goto out;
 
@@ -2865,6 +2964,7 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
 
 	spin_lock_init(&po->bind_lock);
 	mutex_init(&po->pg_vec_lock);
+	po->rollover = NULL;
 	po->prot_hook.func = packet_rcv;
 
 	if (sock->type == SOCK_PACKET)
@@ -2942,6 +3042,9 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 	if (skb == NULL)
 		goto out;
 
+	if (pkt_sk(sk)->pressure)
+		packet_rcv_has_room(pkt_sk(sk), NULL);
+
 	if (pkt_sk(sk)->has_vnet_hdr) {
 		struct virtio_net_hdr vnet_hdr = { 0 };
 
@@ -3485,6 +3588,7 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
 	struct packet_sock *po = pkt_sk(sk);
 	void *data = &val;
 	union tpacket_stats_u st;
+	struct tpacket_rollover_stats rstats;
 
 	if (level != SOL_PACKET)
 		return -ENOPROTOOPT;
@@ -3560,6 +3664,15 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
 			((u32)po->fanout->flags << 24)) :
 		       0);
 		break;
+	case PACKET_ROLLOVER_STATS:
+		if (!po->rollover)
+			return -EINVAL;
+		rstats.tp_all = atomic_long_read(&po->rollover->num);
+		rstats.tp_huge = atomic_long_read(&po->rollover->num_huge);
+		rstats.tp_failed = atomic_long_read(&po->rollover->num_failed);
+		data = &rstats;
+		lv = sizeof(rstats);
+		break;
 	case PACKET_TX_HAS_OFF:
 		val = po->tp_tx_has_off;
 		break;
@@ -3697,6 +3810,8 @@ static unsigned int packet_poll(struct file *file, struct socket *sock,
 			TP_STATUS_KERNEL))
 			mask |= POLLIN | POLLRDNORM;
 	}
+	if (po->pressure && __packet_rcv_has_room(po, NULL) == ROOM_NORMAL)
+		po->pressure = 0;
 	spin_unlock_bh(&sk->sk_receive_queue.lock);
 	spin_lock_bh(&sk->sk_write_queue.lock);
 	if (po->tx_ring.pg_vec) {