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Commit be677730 authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont Committed by David S. Miller
Browse files

Phonet: use atomic for packet TX window 



GPRS TX flow control won't need to lock the underlying socket anymore.

Signed-off-by: default avatarRémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 57c81fff

include/net/phonet/pep.h

+1 −1
Original line number Diff line number Diff line
@@ -35,12 +35,12 @@ struct pep_sock { 
	struct sock		*listener;

	struct sk_buff_head	ctrlreq_queue;

#define PNPIPE_CTRLREQ_MAX	10

	atomic_t		tx_credits;

	int			ifindex;

	u16			peer_type;	/* peer type/subtype */

	u8			pipe_handle;



	u8			rx_credits;

	u8			tx_credits;

	u8			rx_fc;	/* RX flow control */

	u8			tx_fc;	/* TX flow control */

	u8			init_enable;	/* auto-enable at creation */

net/phonet/pep.c

+21 −17
Original line number Diff line number Diff line
@@ -225,6 +225,7 @@ static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb) 
{

	struct pep_sock *pn = pep_sk(sk);

	struct pnpipehdr *hdr = pnp_hdr(skb);

	int wake = 0;



	if (!pskb_may_pull(skb, sizeof(*hdr) + 4))

		return -EINVAL;
@@ -241,16 +242,16 @@ static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb) 
		case PN_LEGACY_FLOW_CONTROL:

			switch (hdr->data[4]) {

			case PEP_IND_BUSY:

				pn->tx_credits = 0;

				atomic_set(&pn->tx_credits, 0);

				break;

			case PEP_IND_READY:

				pn->tx_credits = 1;

				atomic_set(&pn->tx_credits, wake = 1);

				break;

			}

			break;

		case PN_ONE_CREDIT_FLOW_CONTROL:

			if (hdr->data[4] == PEP_IND_READY)

				pn->tx_credits = 1;

				atomic_set(&pn->tx_credits, wake = 1);

			break;

		}

		break;
@@ -258,10 +259,7 @@ static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb) 
	case PN_PEP_IND_ID_MCFC_GRANT_CREDITS:

		if (pn->tx_fc != PN_MULTI_CREDIT_FLOW_CONTROL)

			break;

		if (pn->tx_credits + hdr->data[4] > 0xff)

			pn->tx_credits = 0xff;

		else

			pn->tx_credits += hdr->data[4];

		atomic_add(wake = hdr->data[4], &pn->tx_credits);

		break;



	default:
@@ -269,7 +267,7 @@ static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb) 
				(unsigned)hdr->data[1]);

		return -EOPNOTSUPP;

	}

	if (pn->tx_credits)

	if (wake)

		sk->sk_write_space(sk);

	return 0;

}
@@ -343,7 +341,7 @@ static int pipe_do_rcv(struct sock *sk, struct sk_buff *skb) 
		}

		/* fall through */

	case PNS_PEP_DISABLE_REQ:

		pn->tx_credits = 0;

		atomic_set(&pn->tx_credits, 0);

		pep_reply(sk, skb, PN_PIPE_NO_ERROR, NULL, 0, GFP_ATOMIC);

		break;
@@ -390,7 +388,7 @@ static int pipe_do_rcv(struct sock *sk, struct sk_buff *skb) 
		/* fall through */

	case PNS_PIPE_ENABLED_IND:

		if (!pn_flow_safe(pn->tx_fc)) {

			pn->tx_credits = 1;

			atomic_set(&pn->tx_credits, 1);

			sk->sk_write_space(sk);

		}

		if (sk->sk_state == TCP_ESTABLISHED)
@@ -504,8 +502,9 @@ static int pep_connreq_rcv(struct sock *sk, struct sk_buff *skb) 
	newpn->pn_sk.resource = pn->pn_sk.resource;

	skb_queue_head_init(&newpn->ctrlreq_queue);

	newpn->pipe_handle = pipe_handle;

	atomic_set(&newpn->tx_credits, 0);

	newpn->peer_type = peer_type;

	newpn->rx_credits = newpn->tx_credits = 0;

	newpn->rx_credits = 0;

	newpn->rx_fc = newpn->tx_fc = PN_LEGACY_FLOW_CONTROL;

	newpn->init_enable = enabled;
@@ -821,14 +820,18 @@ static int pipe_skb_send(struct sock *sk, struct sk_buff *skb) 
	struct pep_sock *pn = pep_sk(sk);

	struct pnpipehdr *ph;



	if (pn_flow_safe(pn->tx_fc) &&

	    !atomic_add_unless(&pn->tx_credits, -1, 0)) {

		kfree_skb(skb);

		return -ENOBUFS;

	}



	skb_push(skb, 3);

	skb_reset_transport_header(skb);

	ph = pnp_hdr(skb);

	ph->utid = 0;

	ph->message_id = PNS_PIPE_DATA;

	ph->pipe_handle = pn->pipe_handle;

	if (pn_flow_safe(pn->tx_fc) && pn->tx_credits)

		pn->tx_credits--;



	return pn_skb_send(sk, skb, &pipe_srv);

}
@@ -866,7 +869,7 @@ disabled: 
	BUG_ON(sk->sk_state != TCP_ESTABLISHED);



	/* Wait until flow control allows TX */

	done = pn->tx_credits > 0;

	done = atomic_read(&pn->tx_credits);

	while (!done) {

		DEFINE_WAIT(wait);
@@ -881,7 +884,7 @@ disabled: 


		prepare_to_wait(&sk->sk_socket->wait, &wait,

				TASK_INTERRUPTIBLE);

		done = sk_wait_event(sk, &timeo, pn->tx_credits > 0);

		done = sk_wait_event(sk, &timeo, atomic_read(&pn->tx_credits));

		finish_wait(&sk->sk_socket->wait, &wait);



		if (sk->sk_state != TCP_ESTABLISHED)
@@ -895,7 +898,8 @@ disabled: 
			goto out;

		skb_reserve(skb, MAX_PHONET_HEADER + 3);



		if (sk->sk_state != TCP_ESTABLISHED || !pn->tx_credits)

		if (sk->sk_state != TCP_ESTABLISHED ||

		    !atomic_read(&pn->tx_credits))

			goto disabled; /* sock_alloc_send_skb might sleep */

	}
@@ -917,7 +921,7 @@ int pep_writeable(struct sock *sk) 
{

	struct pep_sock *pn = pep_sk(sk);



	return (sk->sk_state == TCP_ESTABLISHED) ? pn->tx_credits : 0;

	return atomic_read(&pn->tx_credits);

}



int pep_write(struct sock *sk, struct sk_buff *skb)

net/phonet/socket.c

+1 −1
Original line number Diff line number Diff line
@@ -227,7 +227,7 @@ static unsigned int pn_socket_poll(struct file *file, struct socket *sock, 
	if (!mask && sk->sk_state == TCP_CLOSE_WAIT)

		return POLLHUP;



	if (sk->sk_state == TCP_ESTABLISHED && pn->tx_credits)

	if (sk->sk_state == TCP_ESTABLISHED && atomic_read(&pn->tx_credits))

		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;



	return mask;