From: Julian Wiedmann <jwi@linux.ibm.com>
Date: Tue, 18 Jun 2019 20:43:00 +0200
Subject: net/af_iucv: build proper skbs for HiperTransport
Git-commit: 238965b71b968dc5b3c0fe430e946f488322c4b5
Patch-mainline: v5.2-rc1
References: bsc#1142221 LTC#179332
The HiperSockets-based transport path in af_iucv is still too closely
entangled with qeth.
With commit a647a02512ca ("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: a647a02512ca ("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>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
net/iucv/af_iucv.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -13,6 +13,7 @@
#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_me
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_me
skb_trim(skb, skb->dev->mtu);
}
skb->protocol = 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
/* 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;
@@ -1134,7 +1139,8 @@ static int iucv_sock_sendmsg(struct sock
* 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) {