From a3b0b6479700a5b0af2c631cb2ec0fb7a0d978f2 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:09 +0200 Subject: [PATCH 01/12] net: dsa: implement a central TX reallocation procedure At the moment, taggers are left with the task of ensuring that the skb headers are writable (which they aren't, if the frames were cloned for TX timestamping, for flooding by the bridge, etc), and that there is enough space in the skb data area for the DSA tag to be pushed. Moreover, the life of tail taggers is even harder, because they need to ensure that short frames have enough padding, a problem that normal taggers don't have. The principle of the DSA framework is that everything except for the most intimate hardware specifics (like in this case, the actual packing of the DSA tag bits) should be done inside the core, to avoid having code paths that are very rarely tested. So provide a TX reallocation procedure that should cover the known needs of DSA today. Note that this patch also gives the network stack a good hint about the headroom/tailroom it's going to need. Up till now it wasn't doing that. So the reallocation procedure should really be there only for the exceptional cases, and for cloned packets which need to be unshared. Signed-off-by: Vladimir Oltean Tested-by: Christian Eggers # For tail taggers only Tested-by: Kurt Kanzenbach Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/slave.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/net/dsa/slave.c b/net/dsa/slave.c index 3bc5ca40c9fb..c6806eef906f 100644 --- a/net/dsa/slave.c +++ b/net/dsa/slave.c @@ -548,6 +548,30 @@ netdev_tx_t dsa_enqueue_skb(struct sk_buff *skb, struct net_device *dev) } EXPORT_SYMBOL_GPL(dsa_enqueue_skb); +static int dsa_realloc_skb(struct sk_buff *skb, struct net_device *dev) +{ + int needed_headroom = dev->needed_headroom; + int needed_tailroom = dev->needed_tailroom; + + /* For tail taggers, we need to pad short frames ourselves, to ensure + * that the tail tag does not fail at its role of being at the end of + * the packet, once the master interface pads the frame. Account for + * that pad length here, and pad later. + */ + if (unlikely(needed_tailroom && skb->len < ETH_ZLEN)) + needed_tailroom += ETH_ZLEN - skb->len; + /* skb_headroom() returns unsigned int... */ + needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0); + needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0); + + if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb))) + /* No reallocation needed, yay! */ + return 0; + + return pskb_expand_head(skb, needed_headroom, needed_tailroom, + GFP_ATOMIC); +} + static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_slave_priv *p = netdev_priv(dev); @@ -567,6 +591,17 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev) */ dsa_skb_tx_timestamp(p, skb); + if (dsa_realloc_skb(skb, dev)) { + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; + } + + /* needed_tailroom should still be 'warm' in the cache line from + * dsa_realloc_skb(), which has also ensured that padding is safe. + */ + if (dev->needed_tailroom) + eth_skb_pad(skb); + /* Transmit function may have to reallocate the original SKB, * in which case it must have freed it. Only free it here on error. */ @@ -1791,6 +1826,16 @@ int dsa_slave_create(struct dsa_port *port) slave_dev->netdev_ops = &dsa_slave_netdev_ops; if (ds->ops->port_max_mtu) slave_dev->max_mtu = ds->ops->port_max_mtu(ds, port->index); + if (cpu_dp->tag_ops->tail_tag) + slave_dev->needed_tailroom = cpu_dp->tag_ops->overhead; + else + slave_dev->needed_headroom = cpu_dp->tag_ops->overhead; + /* Try to save one extra realloc later in the TX path (in the master) + * by also inheriting the master's needed headroom and tailroom. + * The 8021q driver also does this. + */ + slave_dev->needed_headroom += master->needed_headroom; + slave_dev->needed_tailroom += master->needed_tailroom; SET_NETDEV_DEVTYPE(slave_dev, &dsa_type); netdev_for_each_tx_queue(slave_dev, dsa_slave_set_lockdep_class_one, From 88fda8eefd9a7a7175bf4dad1d02cc0840581111 Mon Sep 17 00:00:00 2001 From: Christian Eggers Date: Sun, 1 Nov 2020 21:16:10 +0200 Subject: [PATCH 02/12] net: dsa: tag_ksz: don't allocate additional memory for padding/tagging The caller (dsa_slave_xmit) guarantees that the frame length is at least ETH_ZLEN and that enough memory for tail tagging is available. Signed-off-by: Christian Eggers Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_ksz.c | 73 ++++++----------------------------------------- 1 file changed, 9 insertions(+), 64 deletions(-) diff --git a/net/dsa/tag_ksz.c b/net/dsa/tag_ksz.c index 0a5aa982c60d..4820dbcedfa2 100644 --- a/net/dsa/tag_ksz.c +++ b/net/dsa/tag_ksz.c @@ -14,46 +14,6 @@ #define KSZ_EGRESS_TAG_LEN 1 #define KSZ_INGRESS_TAG_LEN 1 -static struct sk_buff *ksz_common_xmit(struct sk_buff *skb, - struct net_device *dev, int len) -{ - struct sk_buff *nskb; - int padlen; - - padlen = (skb->len >= ETH_ZLEN) ? 0 : ETH_ZLEN - skb->len; - - if (skb_tailroom(skb) >= padlen + len) { - /* Let dsa_slave_xmit() free skb */ - if (__skb_put_padto(skb, skb->len + padlen, false)) - return NULL; - - nskb = skb; - } else { - nskb = alloc_skb(NET_IP_ALIGN + skb->len + - padlen + len, GFP_ATOMIC); - if (!nskb) - return NULL; - skb_reserve(nskb, NET_IP_ALIGN); - - skb_reset_mac_header(nskb); - skb_set_network_header(nskb, - skb_network_header(skb) - skb->head); - skb_set_transport_header(nskb, - skb_transport_header(skb) - skb->head); - skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len)); - - /* Let skb_put_padto() free nskb, and let dsa_slave_xmit() free - * skb - */ - if (skb_put_padto(nskb, nskb->len + padlen)) - return NULL; - - consume_skb(skb); - } - - return nskb; -} - static struct sk_buff *ksz_common_rcv(struct sk_buff *skb, struct net_device *dev, unsigned int port, unsigned int len) @@ -90,23 +50,18 @@ static struct sk_buff *ksz_common_rcv(struct sk_buff *skb, static struct sk_buff *ksz8795_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_slave_to_port(dev); - struct sk_buff *nskb; u8 *tag; u8 *addr; - nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN); - if (!nskb) - return NULL; - /* Tag encoding */ - tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN); - addr = skb_mac_header(nskb); + tag = skb_put(skb, KSZ_INGRESS_TAG_LEN); + addr = skb_mac_header(skb); *tag = 1 << dp->index; if (is_link_local_ether_addr(addr)) *tag |= KSZ8795_TAIL_TAG_OVERRIDE; - return nskb; + return skb; } static struct sk_buff *ksz8795_rcv(struct sk_buff *skb, struct net_device *dev, @@ -156,18 +111,13 @@ static struct sk_buff *ksz9477_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_slave_to_port(dev); - struct sk_buff *nskb; __be16 *tag; u8 *addr; u16 val; - nskb = ksz_common_xmit(skb, dev, KSZ9477_INGRESS_TAG_LEN); - if (!nskb) - return NULL; - /* Tag encoding */ - tag = skb_put(nskb, KSZ9477_INGRESS_TAG_LEN); - addr = skb_mac_header(nskb); + tag = skb_put(skb, KSZ9477_INGRESS_TAG_LEN); + addr = skb_mac_header(skb); val = BIT(dp->index); @@ -176,7 +126,7 @@ static struct sk_buff *ksz9477_xmit(struct sk_buff *skb, *tag = cpu_to_be16(val); - return nskb; + return skb; } static struct sk_buff *ksz9477_rcv(struct sk_buff *skb, struct net_device *dev, @@ -213,24 +163,19 @@ static struct sk_buff *ksz9893_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_slave_to_port(dev); - struct sk_buff *nskb; u8 *addr; u8 *tag; - nskb = ksz_common_xmit(skb, dev, KSZ_INGRESS_TAG_LEN); - if (!nskb) - return NULL; - /* Tag encoding */ - tag = skb_put(nskb, KSZ_INGRESS_TAG_LEN); - addr = skb_mac_header(nskb); + tag = skb_put(skb, KSZ_INGRESS_TAG_LEN); + addr = skb_mac_header(skb); *tag = BIT(dp->index); if (is_link_local_ether_addr(addr)) *tag |= KSZ9893_TAIL_TAG_OVERRIDE; - return nskb; + return skb; } static const struct dsa_device_ops ksz9893_netdev_ops = { From ef3f72fee286bd270453ce2344feb7295a798508 Mon Sep 17 00:00:00 2001 From: Christian Eggers Date: Sun, 1 Nov 2020 21:16:11 +0200 Subject: [PATCH 03/12] net: dsa: trailer: don't allocate additional memory for padding/tagging The caller (dsa_slave_xmit) guarantees that the frame length is at least ETH_ZLEN and that enough memory for tail tagging is available. Signed-off-by: Christian Eggers Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_trailer.c | 31 ++----------------------------- 1 file changed, 2 insertions(+), 29 deletions(-) diff --git a/net/dsa/tag_trailer.c b/net/dsa/tag_trailer.c index 3a1cc24a4f0a..5b97ede56a0f 100644 --- a/net/dsa/tag_trailer.c +++ b/net/dsa/tag_trailer.c @@ -13,42 +13,15 @@ static struct sk_buff *trailer_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_slave_to_port(dev); - struct sk_buff *nskb; - int padlen; u8 *trailer; - /* - * We have to make sure that the trailer ends up as the very - * last 4 bytes of the packet. This means that we have to pad - * the packet to the minimum ethernet frame size, if necessary, - * before adding the trailer. - */ - padlen = 0; - if (skb->len < 60) - padlen = 60 - skb->len; - - nskb = alloc_skb(NET_IP_ALIGN + skb->len + padlen + 4, GFP_ATOMIC); - if (!nskb) - return NULL; - skb_reserve(nskb, NET_IP_ALIGN); - - skb_reset_mac_header(nskb); - skb_set_network_header(nskb, skb_network_header(skb) - skb->head); - skb_set_transport_header(nskb, skb_transport_header(skb) - skb->head); - skb_copy_and_csum_dev(skb, skb_put(nskb, skb->len)); - consume_skb(skb); - - if (padlen) { - skb_put_zero(nskb, padlen); - } - - trailer = skb_put(nskb, 4); + trailer = skb_put(skb, 4); trailer[0] = 0x80; trailer[1] = 1 << dp->index; trailer[2] = 0x10; trailer[3] = 0x00; - return nskb; + return skb; } static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev, From 9bbda29ae1044bc4c1c01a5b7c44688c4765785f Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:12 +0200 Subject: [PATCH 04/12] net: dsa: tag_qca: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. Cc: John Crispin Cc: Alexander Lobakin Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_qca.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c index 1b9e8507112b..88181b52f480 100644 --- a/net/dsa/tag_qca.c +++ b/net/dsa/tag_qca.c @@ -34,9 +34,6 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev) __be16 *phdr; u16 hdr; - if (skb_cow_head(skb, QCA_HDR_LEN) < 0) - return NULL; - skb_push(skb, QCA_HDR_LEN); memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN); From 9c5c3bd00557e57c1049f7861f11e5e39f0fb42d Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:13 +0200 Subject: [PATCH 05/12] net: dsa: tag_ocelot: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_ocelot.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/net/dsa/tag_ocelot.c b/net/dsa/tag_ocelot.c index 3b468aca5c53..16a1afd5b8e1 100644 --- a/net/dsa/tag_ocelot.c +++ b/net/dsa/tag_ocelot.c @@ -143,13 +143,6 @@ static struct sk_buff *ocelot_xmit(struct sk_buff *skb, struct ocelot_port *ocelot_port; u8 *prefix, *injection; u64 qos_class, rew_op; - int err; - - err = skb_cow_head(skb, OCELOT_TOTAL_TAG_LEN); - if (unlikely(err < 0)) { - netdev_err(netdev, "Cannot make room for tag.\n"); - return NULL; - } ocelot_port = ocelot->ports[dp->index]; From 941f66beb7bb4e0e4726aa31336d9ccc1c3a3dc2 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:14 +0200 Subject: [PATCH 06/12] net: dsa: tag_mtk: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. Cc: DENG Qingfang Cc: Sean Wang Cc: John Crispin Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_mtk.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c index 4cdd9cf428fb..38dcdded74c0 100644 --- a/net/dsa/tag_mtk.c +++ b/net/dsa/tag_mtk.c @@ -34,9 +34,6 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb, * table with VID. */ if (!skb_vlan_tagged(skb)) { - if (skb_cow_head(skb, MTK_HDR_LEN) < 0) - return NULL; - skb_push(skb, MTK_HDR_LEN); memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN); is_vlan_skb = false; From 6ed94135f58372cdec34cafb60f7596893b0b371 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:15 +0200 Subject: [PATCH 07/12] net: dsa: tag_lan9303: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_lan9303.c | 9 --------- 1 file changed, 9 deletions(-) diff --git a/net/dsa/tag_lan9303.c b/net/dsa/tag_lan9303.c index ccfb6f641bbf..aa1318dccaf0 100644 --- a/net/dsa/tag_lan9303.c +++ b/net/dsa/tag_lan9303.c @@ -58,15 +58,6 @@ static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev) __be16 *lan9303_tag; u16 tag; - /* insert a special VLAN tag between the MAC addresses - * and the current ethertype field. - */ - if (skb_cow_head(skb, LAN9303_TAG_LEN) < 0) { - dev_dbg(&dev->dev, - "Cannot make room for the special tag. Dropping packet\n"); - return NULL; - } - /* provide 'LAN9303_TAG_LEN' bytes additional space */ skb_push(skb, LAN9303_TAG_LEN); From c6c4e1237dfe731644e79fa06d073625f28cd945 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:16 +0200 Subject: [PATCH 08/12] net: dsa: tag_edsa: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. Note that the VLAN code path needs a smaller extra headroom than the regular EtherType DSA path. That isn't a problem, because this tagger declares the larger tag length (8 bytes vs 4) as the protocol overhead, so we are covered in both cases. Cc: Andrew Lunn Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_edsa.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/net/dsa/tag_edsa.c b/net/dsa/tag_edsa.c index 120614240319..abf70a29deb4 100644 --- a/net/dsa/tag_edsa.c +++ b/net/dsa/tag_edsa.c @@ -35,8 +35,6 @@ static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev) * current ethertype field if the packet is untagged. */ if (skb->protocol == htons(ETH_P_8021Q)) { - if (skb_cow_head(skb, DSA_HLEN) < 0) - return NULL; skb_push(skb, DSA_HLEN); memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); @@ -60,8 +58,6 @@ static struct sk_buff *edsa_xmit(struct sk_buff *skb, struct net_device *dev) edsa_header[6] &= ~0x10; } } else { - if (skb_cow_head(skb, EDSA_HLEN) < 0) - return NULL; skb_push(skb, EDSA_HLEN); memmove(skb->data, skb->data + EDSA_HLEN, 2 * ETH_ALEN); From 2f0d030c5ffec6660f79a32b4f522155f75a9d71 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:17 +0200 Subject: [PATCH 09/12] net: dsa: tag_brcm: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. Cc: Florian Fainelli Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_brcm.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c index ad72dff8d524..e934dace3922 100644 --- a/net/dsa/tag_brcm.c +++ b/net/dsa/tag_brcm.c @@ -66,9 +66,6 @@ static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb, u16 queue = skb_get_queue_mapping(skb); u8 *brcm_tag; - if (skb_cow_head(skb, BRCM_TAG_LEN) < 0) - return NULL; - /* The Ethernet switch we are interfaced with needs packets to be at * least 64 bytes (including FCS) otherwise they will be discarded when * they enter the switch port logic. When Broadcom tags are enabled, we From 952a06345015867e3bd37f8d9045fc1429637d43 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:18 +0200 Subject: [PATCH 10/12] net: dsa: tag_dsa: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. Similar to the EtherType DSA tagger, the old Marvell tagger can transform an 802.1Q header if present into a DSA tag, so there is no headroom required in that case. But we are ensuring that it exists, regardless (practically speaking, the headroom must be 4 bytes larger than it needs to be). Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_dsa.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c index 0b756fae68a5..63d690a0fca6 100644 --- a/net/dsa/tag_dsa.c +++ b/net/dsa/tag_dsa.c @@ -23,9 +23,6 @@ static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) * the ethertype field for untagged packets. */ if (skb->protocol == htons(ETH_P_8021Q)) { - if (skb_cow_head(skb, 0) < 0) - return NULL; - /* * Construct tagged FROM_CPU DSA tag from 802.1q tag. */ @@ -41,8 +38,6 @@ static struct sk_buff *dsa_xmit(struct sk_buff *skb, struct net_device *dev) dsa_header[2] &= ~0x10; } } else { - if (skb_cow_head(skb, DSA_HLEN) < 0) - return NULL; skb_push(skb, DSA_HLEN); memmove(skb->data, skb->data + DSA_HLEN, 2 * ETH_ALEN); From 9b9826ae117f211bcbdc75db844d5fd8b159fc59 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:19 +0200 Subject: [PATCH 11/12] net: dsa: tag_gswip: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. This one is interesting, the DSA tag is 8 bytes on RX and 4 bytes on TX. Because DSA is unaware of asymmetrical tag lengths, the overhead/needed headroom is declared as 8 bytes and therefore 4 bytes larger than it needs to be. If this becomes a problem, and the GSWIP driver can't be converted to a uniform header length, we might need to make DSA aware of separate RX/TX overhead values. Cc: Hauke Mehrtens Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_gswip.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/net/dsa/tag_gswip.c b/net/dsa/tag_gswip.c index 408d4af390a0..2f5bd5e338ab 100644 --- a/net/dsa/tag_gswip.c +++ b/net/dsa/tag_gswip.c @@ -60,13 +60,8 @@ static struct sk_buff *gswip_tag_xmit(struct sk_buff *skb, struct net_device *dev) { struct dsa_port *dp = dsa_slave_to_port(dev); - int err; u8 *gswip_tag; - err = skb_cow_head(skb, GSWIP_TX_HEADER_LEN); - if (err) - return NULL; - skb_push(skb, GSWIP_TX_HEADER_LEN); gswip_tag = skb->data; From 86c4ad9a7876777c12fd5a7010152e4141fcb94d Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 1 Nov 2020 21:16:20 +0200 Subject: [PATCH 12/12] net: dsa: tag_ar9331: let DSA core deal with TX reallocation Now that we have a central TX reallocation procedure that accounts for the tagger's needed headroom in a generic way, we can remove the skb_cow_head call. Cc: Per Forlin Cc: Oleksij Rempel Signed-off-by: Vladimir Oltean Tested-by: Oleksij Rempel Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- net/dsa/tag_ar9331.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/net/dsa/tag_ar9331.c b/net/dsa/tag_ar9331.c index 55b00694cdba..002cf7f952e2 100644 --- a/net/dsa/tag_ar9331.c +++ b/net/dsa/tag_ar9331.c @@ -31,9 +31,6 @@ static struct sk_buff *ar9331_tag_xmit(struct sk_buff *skb, __le16 *phdr; u16 hdr; - if (skb_cow_head(skb, AR9331_HDR_LEN) < 0) - return NULL; - phdr = skb_push(skb, AR9331_HDR_LEN); hdr = FIELD_PREP(AR9331_HDR_VERSION_MASK, AR9331_HDR_VERSION);