From be677730a0ccb6bedced6f65f2ba8f57a3c607ba Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9mi=20Denis-Courmont?= Date: Wed, 17 Dec 2008 15:48:31 -0800 Subject: Phonet: use atomic for packet TX window MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit GPRS TX flow control won't need to lock the underlying socket anymore. Signed-off-by: Rémi Denis-Courmont Signed-off-by: David S. Miller --- net/phonet/pep.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) (limited to 'net/phonet/pep.c') diff --git a/net/phonet/pep.c b/net/phonet/pep.c index bc6d50f83249..bb3e67849b38 100644 --- a/net/phonet/pep.c +++ b/net/phonet/pep.c @@ -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) -- cgit v1.2.2