Commit ef6af7bd authored by Julian Wiedmann's avatar Julian Wiedmann Committed by Jakub Kicinski
Browse files

net/af_iucv: count packets in the xmit path 



The TX code keeps track of all skbs that are in-flight but haven't
actually been sent out yet. For native IUCV sockets that's not a huge
deal, but with TRANS_HIPER sockets it would be much better if we
didn't need to maintain a list of skb clones.

Note that we actually only care about the _count_ of skbs in this stage
of the TX pipeline. So as prep work for removing the skb tracking on
TRANS_HIPER sockets, keep track of the skb count in a separate variable
and pair any list {enqueue, unlink} with a count {increment, decrement}.

Then replace all occurences where we currently look at the skb list's
fill level.

Signed-off-by: default avatarJulian Wiedmann <jwi@linux.ibm.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c464444f

include/net/iucv/af_iucv.h

+1 −0
Original line number Diff line number Diff line
@@ -128,6 +128,7 @@ struct iucv_sock { 
	u8			flags;

	u16			msglimit;

	u16			msglimit_peer;

	atomic_t		skbs_in_xmit;

	atomic_t		msg_sent;

	atomic_t		msg_recv;

	atomic_t		pendings;

net/iucv/af_iucv.c

+24 −6
Original line number Diff line number Diff line
@@ -182,7 +182,7 @@ static inline int iucv_below_msglim(struct sock *sk) 
	if (sk->sk_state != IUCV_CONNECTED)

		return 1;

	if (iucv->transport == AF_IUCV_TRANS_IUCV)

		return (skb_queue_len(&iucv->send_skb_q) < iucv->path->msglim);

		return (atomic_read(&iucv->skbs_in_xmit) < iucv->path->msglim);

	else

		return ((atomic_read(&iucv->msg_sent) < iucv->msglimit_peer) &&

			(atomic_read(&iucv->pendings) <= 0));
@@ -269,8 +269,10 @@ static int afiucv_hs_send(struct iucv_message *imsg, struct sock *sock, 
	}



	skb_queue_tail(&iucv->send_skb_q, nskb);

	atomic_inc(&iucv->skbs_in_xmit);

	err = dev_queue_xmit(skb);

	if (net_xmit_eval(err)) {

		atomic_dec(&iucv->skbs_in_xmit);

		skb_unlink(nskb, &iucv->send_skb_q);

		kfree_skb(nskb);

	} else {
@@ -424,7 +426,7 @@ static void iucv_sock_close(struct sock *sk) 
		sk->sk_state = IUCV_CLOSING;

		sk->sk_state_change(sk);



		if (!err && !skb_queue_empty(&iucv->send_skb_q)) {

		if (!err && atomic_read(&iucv->skbs_in_xmit) > 0) {

			if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime)

				timeo = sk->sk_lingertime;

			else
@@ -491,6 +493,7 @@ static struct sock *iucv_sock_alloc(struct socket *sock, int proto, gfp_t prio, 
	atomic_set(&iucv->pendings, 0);

	iucv->flags = 0;

	iucv->msglimit = 0;

	atomic_set(&iucv->skbs_in_xmit, 0);

	atomic_set(&iucv->msg_sent, 0);

	atomic_set(&iucv->msg_recv, 0);

	iucv->path = NULL;
@@ -1055,6 +1058,7 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, 
		}

	} else { /* Classic VM IUCV transport */

		skb_queue_tail(&iucv->send_skb_q, skb);

		atomic_inc(&iucv->skbs_in_xmit);



		if (((iucv->path->flags & IUCV_IPRMDATA) & iucv->flags) &&

		    skb->len <= 7) {
@@ -1063,6 +1067,7 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, 
			/* on success: there is no message_complete callback */

			/* for an IPRMDATA msg; remove skb from send queue   */

			if (err == 0) {

				atomic_dec(&iucv->skbs_in_xmit);

				skb_unlink(skb, &iucv->send_skb_q);

				kfree_skb(skb);

			}
@@ -1071,6 +1076,7 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, 
			/* IUCV_IPRMDATA path flag is set... sever path */

			if (err == 0x15) {

				pr_iucv->path_sever(iucv->path, NULL);

				atomic_dec(&iucv->skbs_in_xmit);

				skb_unlink(skb, &iucv->send_skb_q);

				err = -EPIPE;

				goto fail;
@@ -1109,6 +1115,8 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, 
			} else {

				err = -EPIPE;

			}



			atomic_dec(&iucv->skbs_in_xmit);

			skb_unlink(skb, &iucv->send_skb_q);

			goto fail;

		}
@@ -1748,10 +1756,14 @@ static void iucv_callback_txdone(struct iucv_path *path, 
{

	struct sock *sk = path->private;

	struct sk_buff *this = NULL;

	struct sk_buff_head *list = &iucv_sk(sk)->send_skb_q;

	struct sk_buff_head *list;

	struct sk_buff *list_skb;

	struct iucv_sock *iucv;

	unsigned long flags;



	iucv = iucv_sk(sk);

	list = &iucv->send_skb_q;



	bh_lock_sock(sk);



	spin_lock_irqsave(&list->lock, flags);
@@ -1761,8 +1773,11 @@ static void iucv_callback_txdone(struct iucv_path *path, 
			break;

		}

	}

	if (this)

	if (this) {

		atomic_dec(&iucv->skbs_in_xmit);

		__skb_unlink(this, list);

	}



	spin_unlock_irqrestore(&list->lock, flags);



	if (this) {
@@ -1772,7 +1787,7 @@ static void iucv_callback_txdone(struct iucv_path *path, 
	}



	if (sk->sk_state == IUCV_CLOSING) {

		if (skb_queue_empty(&iucv_sk(sk)->send_skb_q)) {

		if (atomic_read(&iucv->skbs_in_xmit) == 0) {

			sk->sk_state = IUCV_CLOSED;

			sk->sk_state_change(sk);

		}
@@ -2150,6 +2165,7 @@ static void afiucv_hs_callback_txnotify(struct sk_buff *skb, 
		if (skb_shinfo(list_skb) == skb_shinfo(skb)) {

			switch (n) {

			case TX_NOTIFY_OK:

				atomic_dec(&iucv->skbs_in_xmit);

				__skb_unlink(list_skb, list);

				kfree_skb(list_skb);

				iucv_sock_wake_msglim(sk);
@@ -2158,6 +2174,7 @@ static void afiucv_hs_callback_txnotify(struct sk_buff *skb, 
				atomic_inc(&iucv->pendings);

				break;

			case TX_NOTIFY_DELAYED_OK:

				atomic_dec(&iucv->skbs_in_xmit);

				__skb_unlink(list_skb, list);

				atomic_dec(&iucv->pendings);

				if (atomic_read(&iucv->pendings) <= 0)
@@ -2169,6 +2186,7 @@ static void afiucv_hs_callback_txnotify(struct sk_buff *skb, 
			case TX_NOTIFY_TPQFULL: /* not yet used */

			case TX_NOTIFY_GENERALERROR:

			case TX_NOTIFY_DELAYED_GENERALERROR:

				atomic_dec(&iucv->skbs_in_xmit);

				__skb_unlink(list_skb, list);

				kfree_skb(list_skb);

				if (sk->sk_state == IUCV_CONNECTED) {
@@ -2183,7 +2201,7 @@ static void afiucv_hs_callback_txnotify(struct sk_buff *skb, 
	spin_unlock_irqrestore(&list->lock, flags);



	if (sk->sk_state == IUCV_CLOSING) {

		if (skb_queue_empty(&iucv_sk(sk)->send_skb_q)) {

		if (atomic_read(&iucv->skbs_in_xmit) == 0) {

			sk->sk_state = IUCV_CLOSED;

			sk->sk_state_change(sk);

		}