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net/af_iucv: build proper skbs for HiperTransport

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The HiperSockets-based transport path in af_iucv is still too closely
entangled with qeth.
With commit a647a02512 ("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: a647a02512 ("s390/qeth: speed-up L3 IQD xmit")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Julian Wiedmann 2019-06-18 20:43:00 +02:00 committed by David S. Miller
parent fdbf632691
commit 238965b71b
1 changed files with 11 additions and 5 deletions
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16
net/iucv/af_iucv.c
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@ -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) {