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Commit 0fd7bac6 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: relax rcvbuf limits 



skb->truesize might be big even for a small packet.

Its even bigger after commit 87fb4b7b (net: more accurate skb
truesize) and big MTU.

We should allow queueing at least one packet per receiver, even with a
low RCVBUF setting.

Reported-by: default avatarMichal Simek <monstr@monstr.eu>
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a0a129f8

include/net/sock.h

+3 −1
Original line number Diff line number Diff line
@@ -637,12 +637,14 @@ static inline void __sk_add_backlog(struct sock *sk, struct sk_buff *skb) 


/*

 * Take into account size of receive queue and backlog queue

 * Do not take into account this skb truesize,

 * to allow even a single big packet to come.

 */

static inline bool sk_rcvqueues_full(const struct sock *sk, const struct sk_buff *skb)

{

	unsigned int qsize = sk->sk_backlog.len + atomic_read(&sk->sk_rmem_alloc);



	return qsize + skb->truesize > sk->sk_rcvbuf;

	return qsize > sk->sk_rcvbuf;

}



/* The per-socket spinlock must be held here. */

net/core/sock.c

+1 −5
Original line number Diff line number Diff line
@@ -288,11 +288,7 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) 
	unsigned long flags;

	struct sk_buff_head *list = &sk->sk_receive_queue;



	/* Cast sk->rcvbuf to unsigned... It's pointless, but reduces

	   number of warnings when compiling with -W --ANK

	 */

	if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=

	    (unsigned)sk->sk_rcvbuf) {

	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) {

		atomic_inc(&sk->sk_drops);

		trace_sock_rcvqueue_full(sk, skb);

		return -ENOMEM;

net/packet/af_packet.c

+2 −4
Original line number Diff line number Diff line
@@ -1630,8 +1630,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, 
	if (snaplen > res)

		snaplen = res;



	if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=

	    (unsigned)sk->sk_rcvbuf)

	if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)

		goto drop_n_acct;



	if (skb_shared(skb)) {
@@ -1762,8 +1761,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, 
	if (po->tp_version <= TPACKET_V2) {

		if (macoff + snaplen > po->rx_ring.frame_size) {

			if (po->copy_thresh &&

				atomic_read(&sk->sk_rmem_alloc) + skb->truesize

				< (unsigned)sk->sk_rcvbuf) {

			    atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf) {

				if (skb_shared(skb)) {

					copy_skb = skb_clone(skb, GFP_ATOMIC);

				} else {