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Commit 238965b7 authored by Julian Wiedmann's avatar Julian Wiedmann Committed by David S. Miller
Browse files

net/af_iucv: build proper skbs for HiperTransport 



The HiperSockets-based transport path in af_iucv is still too closely
entangled with qeth.
With commit a647a025 ("s390/qeth: speed-up L3 IQD xmit"), the
relevant xmit code in qeth has begun to use skb_cow_head(). So to avoid
unnecessary skb head expansions, af_iucv must learn to
1) respect dev->needed_headroom when allocating skbs, and
2) drop the header reference before cloning the skb.

While at it, also stop hard-coding the LL-header creation stage and just
use the appropriate helper.

Fixes: a647a025 ("s390/qeth: speed-up L3 IQD xmit")
Signed-off-by: default avatarJulian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fdbf6326

net/iucv/af_iucv.c

+11 −5
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt



#include <linux/module.h>

#include <linux/netdevice.h>

#include <linux/types.h>

#include <linux/list.h>

#include <linux/errno.h>
@@ -347,14 +348,14 @@ static int afiucv_hs_send(struct iucv_message *imsg, struct sock *sock, 
	if (imsg)

		memcpy(&phs_hdr->iucv_hdr, imsg, sizeof(struct iucv_message));



	skb_push(skb, ETH_HLEN);

	memset(skb->data, 0, ETH_HLEN);



	skb->dev = iucv->hs_dev;

	if (!skb->dev) {

		err = -ENODEV;

		goto err_free;

	}



	dev_hard_header(skb, skb->dev, ETH_P_AF_IUCV, NULL, NULL, skb->len);



	if (!(skb->dev->flags & IFF_UP) || !netif_carrier_ok(skb->dev)) {

		err = -ENETDOWN;

		goto err_free;
@@ -367,6 +368,8 @@ static int afiucv_hs_send(struct iucv_message *imsg, struct sock *sock, 
		skb_trim(skb, skb->dev->mtu);

	}

	skb->protocol = cpu_to_be16(ETH_P_AF_IUCV);



	__skb_header_release(skb);

	nskb = skb_clone(skb, GFP_ATOMIC);

	if (!nskb) {

		err = -ENOMEM;
@@ -466,12 +469,14 @@ static void iucv_sever_path(struct sock *sk, int with_user_data) 
/* Send controlling flags through an IUCV socket for HIPER transport */

static int iucv_send_ctrl(struct sock *sk, u8 flags)

{

	struct iucv_sock *iucv = iucv_sk(sk);

	int err = 0;

	int blen;

	struct sk_buff *skb;

	u8 shutdown = 0;



	blen = sizeof(struct af_iucv_trans_hdr) + ETH_HLEN;

	blen = sizeof(struct af_iucv_trans_hdr) +

	       LL_RESERVED_SPACE(iucv->hs_dev);

	if (sk->sk_shutdown & SEND_SHUTDOWN) {

		/* controlling flags should be sent anyway */

		shutdown = sk->sk_shutdown;
@@ -1133,7 +1138,8 @@ static int iucv_sock_sendmsg(struct socket *sock, struct msghdr *msg, 
	 * segmented records using the MSG_EOR flag), but

	 * for SOCK_STREAM we might want to improve it in future */

	if (iucv->transport == AF_IUCV_TRANS_HIPER) {

		headroom = sizeof(struct af_iucv_trans_hdr) + ETH_HLEN;

		headroom = sizeof(struct af_iucv_trans_hdr) +

			   LL_RESERVED_SPACE(iucv->hs_dev);

		linear = len;

	} else {

		if (len < PAGE_SIZE) {