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authorJulian Wiedmann <jwi@linux.vnet.ibm.com>2017-03-23 14:55:09 +0100
committerDavid S. Miller <davem@davemloft.net>2017-03-24 12:40:00 -0700
commitacd9776b5c45ef02d1a210969a6fcc058afb76e3 (patch)
tree649f27860a02946638fa22a842c35ca36f2457c4 /drivers/s390
parent7d969d2e8890f546c8cec634b3aa5f57d4eef883 (diff)
downloadlinux-acd9776b5c45ef02d1a210969a6fcc058afb76e3.tar.bz2
s390/qeth: no ETH header for outbound AF_IUCV
With AF_IUCV traffic, the skb passed to hard_start_xmit() has a 14 byte slot at skb->data, intended for an ETH header. qeth_l3_fill_af_iucv_hdr() fills this ETH header... and then immediately moves it to the skb's headroom, where it disappears and is never seen again. But it's still possible for us to return NETDEV_TX_BUSY after the skb has been modified. Since we didn't get a private copy of the skb, the next time the skb is delivered to hard_start_xmit() it no longer has the expected layout (we moved the ETH header to the headroom, so skb->data now starts at the IUCV_TRANS header). So when qeth_l3_fill_af_iucv_hdr() does another round of rebuilding, the resulting qeth header ends up all wrong. On transmission, the buffer is then rejected by the HiperSockets device with SBALF15 = x'04'. When this error is passed back to af_iucv as TX_NOTIFY_UNREACHABLE, it tears down the offending socket. As the ETH header for AF_IUCV serves no purpose, just align the code to what we do for IP traffic on L3 HiperSockets: keep the ETH header at skb->data, and pass down data_offset = ETH_HLEN to qeth_fill_buffer(). When mapping the payload into the SBAL elements, the ETH header is then stripped off. This avoids the skb manipulations in qeth_l3_fill_af_iucv_hdr(), and any buffer re-entering hard_start_xmit() after NETDEV_TX_BUSY is now processed properly. Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com> Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/s390')
-rw-r--r--drivers/s390/net/qeth_l3_main.c15
1 files changed, 4 insertions, 11 deletions
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 72aa9537a725..653f0fb76573 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2609,17 +2609,13 @@ static void qeth_l3_fill_af_iucv_hdr(struct qeth_card *card,
char daddr[16];
struct af_iucv_trans_hdr *iucv_hdr;
- skb_pull(skb, 14);
- card->dev->header_ops->create(skb, card->dev, 0,
- card->dev->dev_addr, card->dev->dev_addr,
- card->dev->addr_len);
- skb_pull(skb, 14);
- iucv_hdr = (struct af_iucv_trans_hdr *)skb->data;
memset(hdr, 0, sizeof(struct qeth_hdr));
hdr->hdr.l3.id = QETH_HEADER_TYPE_LAYER3;
hdr->hdr.l3.ext_flags = 0;
- hdr->hdr.l3.length = skb->len;
+ hdr->hdr.l3.length = skb->len - ETH_HLEN;
hdr->hdr.l3.flags = QETH_HDR_IPV6 | QETH_CAST_UNICAST;
+
+ iucv_hdr = (struct af_iucv_trans_hdr *) (skb->data + ETH_HLEN);
memset(daddr, 0, sizeof(daddr));
daddr[0] = 0xfe;
daddr[1] = 0x80;
@@ -2823,10 +2819,7 @@ static int qeth_l3_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
if ((card->info.type == QETH_CARD_TYPE_IQD) &&
!skb_is_nonlinear(skb)) {
new_skb = skb;
- if (new_skb->protocol == ETH_P_AF_IUCV)
- data_offset = 0;
- else
- data_offset = ETH_HLEN;
+ data_offset = ETH_HLEN;
hdr = kmem_cache_alloc(qeth_core_header_cache, GFP_ATOMIC);
if (!hdr)
goto tx_drop;