From bc3ab70584696cb798b9e1e0ac8e6ced5fd4c3b8 Mon Sep 17 00:00:00 2001 From: Julian Wiedmann Date: Fri, 1 Dec 2017 10:14:49 +0100 Subject: s390/qeth: fix thinko in IPv4 multicast address tracking Commit 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback") reworked how secondary addresses are managed for qeth devices. Instead of dropping & subsequently re-adding all addresses on every ndo_set_rx_mode() call, qeth now keeps track of the addresses that are currently registered with the HW. On a ndo_set_rx_mode(), we thus only need to do (de-)registration requests for the addresses that have actually changed. On L3 devices, the lookup for IPv4 Multicast addresses checks the wrong hashtable - and thus never finds a match. As a result, we first delete *all* such addresses, and then re-add them again. So each set_rx_mode() causes a short period where the IPv4 Multicast addresses are not registered, and the card stops forwarding inbound traffic for them. Fix this by setting the ->is_multicast flag on the lookup object, thus enabling qeth_l3_ip_from_hash() to search the correct hashtable and find a match there. Fixes: 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback") Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller --- drivers/s390/net/qeth_l3_main.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/s390') diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index aadd384316a3..e79936b50698 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -1376,6 +1376,7 @@ qeth_l3_add_mc_to_hash(struct qeth_card *card, struct in_device *in4_dev) tmp->u.a4.addr = be32_to_cpu(im4->multiaddr); memcpy(tmp->mac, buf, sizeof(tmp->mac)); + tmp->is_multicast = 1; ipm = qeth_l3_ip_from_hash(card, tmp); if (ipm) { -- cgit v1.2.3 From 6d69b1f1eb7a2edf8a3547f361c61f2538e054bb Mon Sep 17 00:00:00 2001 From: Julian Wiedmann Date: Fri, 1 Dec 2017 10:14:50 +0100 Subject: s390/qeth: fix GSO throughput regression Using GSO with small MTUs currently results in a substantial throughput regression - which is caused by how qeth needs to map non-linear skbs into its IO buffer elements: compared to a linear skb, each GSO-segmented skb effectively consumes twice as many buffer elements (ie two instead of one) due to the additional header-only part. This causes the Output Queue to be congested with low-utilized IO buffers. Fix this as follows: If the MSS is low enough so that a non-SG GSO segmentation produces order-0 skbs (currently ~3500 byte), opt out from NETIF_F_SG. This is where we anticipate the biggest savings, since an SG-enabled GSO segmentation produces skbs that always consume at least two buffer elements. Larger MSS values continue to get a SG-enabled GSO segmentation, since 1) the relative overhead of the additional header-only buffer element becomes less noticeable, and 2) the linearization overhead increases. With the throughput regression fixed, re-enable NETIF_F_SG by default to reap the significant CPU savings of GSO. Fixes: 5722963a8e83 ("qeth: do not turn on SG per default") Reported-by: Nils Hoppmann Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller --- drivers/s390/net/qeth_core.h | 3 +++ drivers/s390/net/qeth_core_main.c | 31 +++++++++++++++++++++++++++++++ drivers/s390/net/qeth_l2_main.c | 2 ++ drivers/s390/net/qeth_l3_main.c | 2 ++ 4 files changed, 38 insertions(+) (limited to 'drivers/s390') diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h index 9cd569ef43ec..15015a24f8ad 100644 --- a/drivers/s390/net/qeth_core.h +++ b/drivers/s390/net/qeth_core.h @@ -987,6 +987,9 @@ struct qeth_cmd_buffer *qeth_get_setassparms_cmd(struct qeth_card *, int qeth_set_features(struct net_device *, netdev_features_t); void qeth_recover_features(struct net_device *dev); netdev_features_t qeth_fix_features(struct net_device *, netdev_features_t); +netdev_features_t qeth_features_check(struct sk_buff *skb, + struct net_device *dev, + netdev_features_t features); int qeth_vm_request_mac(struct qeth_card *card); int qeth_push_hdr(struct sk_buff *skb, struct qeth_hdr **hdr, unsigned int len); diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index 49b9efeba1bd..d9b0e07d4fa7 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -19,6 +19,11 @@ #include #include #include +#include +#include +#include +#include + #include #include @@ -6438,6 +6443,32 @@ netdev_features_t qeth_fix_features(struct net_device *dev, } EXPORT_SYMBOL_GPL(qeth_fix_features); +netdev_features_t qeth_features_check(struct sk_buff *skb, + struct net_device *dev, + netdev_features_t features) +{ + /* GSO segmentation builds skbs with + * a (small) linear part for the headers, and + * page frags for the data. + * Compared to a linear skb, the header-only part consumes an + * additional buffer element. This reduces buffer utilization, and + * hurts throughput. So compress small segments into one element. + */ + if (netif_needs_gso(skb, features)) { + /* match skb_segment(): */ + unsigned int doffset = skb->data - skb_mac_header(skb); + unsigned int hsize = skb_shinfo(skb)->gso_size; + unsigned int hroom = skb_headroom(skb); + + /* linearize only if resulting skb allocations are order-0: */ + if (SKB_DATA_ALIGN(hroom + doffset + hsize) <= SKB_MAX_HEAD(0)) + features &= ~NETIF_F_SG; + } + + return vlan_features_check(skb, features); +} +EXPORT_SYMBOL_GPL(qeth_features_check); + static int __init qeth_core_init(void) { int rc; diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index d2537c09126d..85162712d207 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -960,6 +960,7 @@ static const struct net_device_ops qeth_l2_netdev_ops = { .ndo_stop = qeth_l2_stop, .ndo_get_stats = qeth_get_stats, .ndo_start_xmit = qeth_l2_hard_start_xmit, + .ndo_features_check = qeth_features_check, .ndo_validate_addr = eth_validate_addr, .ndo_set_rx_mode = qeth_l2_set_rx_mode, .ndo_do_ioctl = qeth_do_ioctl, @@ -1010,6 +1011,7 @@ static int qeth_l2_setup_netdev(struct qeth_card *card) if (card->info.type == QETH_CARD_TYPE_OSD && !card->info.guestlan) { card->dev->hw_features = NETIF_F_SG; card->dev->vlan_features = NETIF_F_SG; + card->dev->features |= NETIF_F_SG; /* OSA 3S and earlier has no RX/TX support */ if (qeth_is_supported(card, IPA_OUTBOUND_CHECKSUM)) { card->dev->hw_features |= NETIF_F_IP_CSUM; diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index e79936b50698..46a841258fc8 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -2918,6 +2918,7 @@ static const struct net_device_ops qeth_l3_osa_netdev_ops = { .ndo_stop = qeth_l3_stop, .ndo_get_stats = qeth_get_stats, .ndo_start_xmit = qeth_l3_hard_start_xmit, + .ndo_features_check = qeth_features_check, .ndo_validate_addr = eth_validate_addr, .ndo_set_rx_mode = qeth_l3_set_multicast_list, .ndo_do_ioctl = qeth_do_ioctl, @@ -2958,6 +2959,7 @@ static int qeth_l3_setup_netdev(struct qeth_card *card) card->dev->vlan_features = NETIF_F_SG | NETIF_F_RXCSUM | NETIF_F_IP_CSUM | NETIF_F_TSO; + card->dev->features |= NETIF_F_SG; } } } else if (card->info.type == QETH_CARD_TYPE_IQD) { -- cgit v1.2.3 From 0cbff6d4546613330a1c5f139f5c368e4ce33ca1 Mon Sep 17 00:00:00 2001 From: Julian Wiedmann Date: Fri, 1 Dec 2017 10:14:51 +0100 Subject: s390/qeth: build max size GSO skbs on L2 devices The current GSO skb size limit was copy&pasted over from the L3 path, where it is needed due to a TSO limitation. As L2 devices don't offer TSO support (and thus all GSO skbs are segmented before they reach the driver), there's no reason to restrict the stack in how large it may build the GSO skbs. Fixes: d52aec97e5bc ("qeth: enable scatter/gather in layer 2 mode") Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller --- drivers/s390/net/qeth_l2_main.c | 2 -- drivers/s390/net/qeth_l3_main.c | 4 ++-- 2 files changed, 2 insertions(+), 4 deletions(-) (limited to 'drivers/s390') diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index 85162712d207..f21c94810373 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -1030,8 +1030,6 @@ static int qeth_l2_setup_netdev(struct qeth_card *card) card->info.broadcast_capable = 1; qeth_l2_request_initial_mac(card); - card->dev->gso_max_size = (QETH_MAX_BUFFER_ELEMENTS(card) - 1) * - PAGE_SIZE; SET_NETDEV_DEV(card->dev, &card->gdev->dev); netif_napi_add(card->dev, &card->napi, qeth_poll, QETH_NAPI_WEIGHT); netif_carrier_off(card->dev); diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index 46a841258fc8..2a25f20566d8 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -2987,8 +2987,8 @@ static int qeth_l3_setup_netdev(struct qeth_card *card) NETIF_F_HW_VLAN_CTAG_RX | NETIF_F_HW_VLAN_CTAG_FILTER; netif_keep_dst(card->dev); - card->dev->gso_max_size = (QETH_MAX_BUFFER_ELEMENTS(card) - 1) * - PAGE_SIZE; + netif_set_gso_max_size(card->dev, (QETH_MAX_BUFFER_ELEMENTS(card) - 1) * + PAGE_SIZE); SET_NETDEV_DEV(card->dev, &card->gdev->dev); netif_napi_add(card->dev, &card->napi, qeth_poll, QETH_NAPI_WEIGHT); -- cgit v1.2.3