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From: Vladimir Oltean <vladimir.oltean@nxp.com>
To: netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	DENG Qingfang <dqfext@gmail.com>, John Crispin <john@phrozen.org>,
	Sean Wang <sean.wang@mediatek.com>,
	Landen Chao <Landen.Chao@mediatek.com>
Subject: [RFC PATCH net-next 2/4] net: dsa: create a helper which allocates space for EtherType DSA headers
Date: Mon,  9 Aug 2021 14:57:20 +0300	[thread overview]
Message-ID: <20210809115722.351383-3-vladimir.oltean@nxp.com> (raw)
In-Reply-To: <20210809115722.351383-1-vladimir.oltean@nxp.com>

Hide away the memmove used by DSA EtherType header taggers to shift the
MAC SA and DA to the left to make room for the header, after they've
called skb_push(). The call to skb_push() is still left explicit in
drivers, to be symmetric with dsa_strip_etype_header, and because not
all callers can be refactored to do it (for example, brcm_tag_xmit_ll
has common code for a pre-Ethernet DSA tag and an EtherType DSA tag).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 net/dsa/dsa_priv.h    | 29 +++++++++++++++++++++++++++++
 net/dsa/tag_brcm.c    |  4 ++--
 net/dsa/tag_dsa.c     |  4 ++--
 net/dsa/tag_lan9303.c |  2 +-
 net/dsa/tag_mtk.c     |  2 +-
 net/dsa/tag_qca.c     |  2 +-
 net/dsa/tag_rtl4_a.c  |  2 +-
 net/dsa/tag_sja1105.c |  3 +--
 8 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 8a12ec1f9d21..28e1fbe64ee0 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -478,6 +478,35 @@ static inline void dsa_strip_etype_header(struct sk_buff *skb, int len)
 	memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - len, 2 * ETH_ALEN);
 }
 
+/* Helper for creating space for DSA header tags in TX path packets.
+ * Must not be called before skb_push(len).
+ *
+ * Before:
+ *
+ *       <<<<<<<   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
+ * ^     <<<<<<<   +-----------------------+-----------------------+-------+
+ * |     <<<<<<<   |    Destination MAC    |      Source MAC       | EType |
+ * |               +-----------------------+-----------------------+-------+
+ * <----- len ----->
+ * |
+ * |
+ * skb->data
+ *
+ * After:
+ *
+ * |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
+ * +-----------------------+-----------------------+---------------+-------+
+ * |    Destination MAC    |      Source MAC       |  DSA header   | EType |
+ * +-----------------------+-----------------------+---------------+-------+
+ * ^                                               |               |
+ * |                                               <----- len ----->
+ * skb->data
+ */
+static inline void dsa_alloc_etype_header(struct sk_buff *skb, int len)
+{
+	memmove(skb->data, skb->data + len, 2 * ETH_ALEN);
+}
+
 /* switch.c */
 int dsa_switch_register_notifier(struct dsa_switch *ds);
 void dsa_switch_unregister_notifier(struct dsa_switch *ds);
diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
index 2fc546b31ad8..c62a89bb8de3 100644
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -99,7 +99,7 @@ static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
 	skb_push(skb, BRCM_TAG_LEN);
 
 	if (offset)
-		memmove(skb->data, skb->data + BRCM_TAG_LEN, offset);
+		dsa_alloc_etype_header(skb, BRCM_TAG_LEN);
 
 	brcm_tag = skb->data + offset;
 
@@ -228,7 +228,7 @@ static struct sk_buff *brcm_leg_tag_xmit(struct sk_buff *skb,
 
 	skb_push(skb, BRCM_LEG_TAG_LEN);
 
-	memmove(skb->data, skb->data + BRCM_LEG_TAG_LEN, 2 * ETH_ALEN);
+	dsa_alloc_etype_header(skb, BRCM_LEG_TAG_LEN);
 
 	brcm_tag = skb->data + 2 * ETH_ALEN;
 
diff --git a/net/dsa/tag_dsa.c b/net/dsa/tag_dsa.c
index ad9c841c998f..ab2c63859d12 100644
--- a/net/dsa/tag_dsa.c
+++ b/net/dsa/tag_dsa.c
@@ -166,7 +166,7 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
 	if (skb->protocol == htons(ETH_P_8021Q)) {
 		if (extra) {
 			skb_push(skb, extra);
-			memmove(skb->data, skb->data + extra, 2 * ETH_ALEN);
+			dsa_alloc_etype_header(skb, extra);
 		}
 
 		/* Construct tagged DSA tag from 802.1Q tag. */
@@ -181,7 +181,7 @@ static struct sk_buff *dsa_xmit_ll(struct sk_buff *skb, struct net_device *dev,
 		}
 	} else {
 		skb_push(skb, DSA_HLEN + extra);
-		memmove(skb->data, skb->data + DSA_HLEN + extra, 2 * ETH_ALEN);
+		dsa_alloc_etype_header(skb, DSA_HLEN + extra);
 
 		/* Construct untagged DSA tag. */
 		dsa_header = skb->data + 2 * ETH_ALEN + extra;
diff --git a/net/dsa/tag_lan9303.c b/net/dsa/tag_lan9303.c
index af13c0a9cb41..e8ad3727433e 100644
--- a/net/dsa/tag_lan9303.c
+++ b/net/dsa/tag_lan9303.c
@@ -62,7 +62,7 @@ static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
 	skb_push(skb, LAN9303_TAG_LEN);
 
 	/* make room between MACs and Ether-Type */
-	memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN);
+	dsa_alloc_etype_header(skb, LAN9303_TAG_LEN);
 
 	lan9303_tag = (__be16 *)(skb->data + 2 * ETH_ALEN);
 	tag = lan9303_xmit_use_arl(dp, skb->data) ?
diff --git a/net/dsa/tag_mtk.c b/net/dsa/tag_mtk.c
index 6a78e9f146e5..06d1cfc6d19b 100644
--- a/net/dsa/tag_mtk.c
+++ b/net/dsa/tag_mtk.c
@@ -41,7 +41,7 @@ static struct sk_buff *mtk_tag_xmit(struct sk_buff *skb,
 	default:
 		xmit_tpid = MTK_HDR_XMIT_UNTAGGED;
 		skb_push(skb, MTK_HDR_LEN);
-		memmove(skb->data, skb->data + MTK_HDR_LEN, 2 * ETH_ALEN);
+		dsa_alloc_etype_header(skb, MTK_HDR_LEN);
 	}
 
 	mtk_tag = skb->data + 2 * ETH_ALEN;
diff --git a/net/dsa/tag_qca.c b/net/dsa/tag_qca.c
index f9fc881da591..c68a814188e7 100644
--- a/net/dsa/tag_qca.c
+++ b/net/dsa/tag_qca.c
@@ -36,7 +36,7 @@ static struct sk_buff *qca_tag_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	skb_push(skb, QCA_HDR_LEN);
 
-	memmove(skb->data, skb->data + QCA_HDR_LEN, 2 * ETH_ALEN);
+	dsa_alloc_etype_header(skb, QCA_HDR_LEN);
 	phdr = (__be16 *)(skb->data + 2 * ETH_ALEN);
 
 	/* Set the version field, and set destination port information */
diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c
index ff8707ff0c5b..06e901eda298 100644
--- a/net/dsa/tag_rtl4_a.c
+++ b/net/dsa/tag_rtl4_a.c
@@ -47,7 +47,7 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
 		   dp->index);
 	skb_push(skb, RTL4_A_HDR_LEN);
 
-	memmove(skb->data, skb->data + RTL4_A_HDR_LEN, 2 * ETH_ALEN);
+	dsa_alloc_etype_header(skb, RTL4_A_HDR_LEN);
 	tag = skb->data + 2 * ETH_ALEN;
 
 	/* Set Ethertype */
diff --git a/net/dsa/tag_sja1105.c b/net/dsa/tag_sja1105.c
index 5e8234079d08..939161822f31 100644
--- a/net/dsa/tag_sja1105.c
+++ b/net/dsa/tag_sja1105.c
@@ -245,8 +245,7 @@ static struct sk_buff *sja1110_xmit(struct sk_buff *skb,
 
 	skb_push(skb, SJA1110_HEADER_LEN);
 
-	/* Move Ethernet header to the left, making space for DSA tag */
-	memmove(skb->data, skb->data + SJA1110_HEADER_LEN, 2 * ETH_ALEN);
+	dsa_alloc_etype_header(skb, SJA1110_HEADER_LEN);
 
 	trailer_pos = skb->len;
 
-- 
2.25.1


  parent reply	other threads:[~2021-08-09 11:57 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-09 11:57 [RFC PATCH net-next 0/4] DSA tagger helpers Vladimir Oltean
2021-08-09 11:57 ` [RFC PATCH net-next 1/4] net: dsa: create a helper that strips EtherType DSA headers on RX Vladimir Oltean
2021-08-10  1:01   ` Andrew Lunn
2021-08-10  9:18   ` Florian Fainelli
2021-08-11 13:23   ` Linus Walleij
2021-08-09 11:57 ` Vladimir Oltean [this message]
2021-08-10  1:03   ` [RFC PATCH net-next 2/4] net: dsa: create a helper which allocates space for EtherType DSA headers Andrew Lunn
2021-08-10  9:21   ` Florian Fainelli
2021-08-11 13:24   ` Linus Walleij
2021-08-09 11:57 ` [RFC PATCH net-next 3/4] net: dsa: create a helper for locating EtherType DSA headers on RX Vladimir Oltean
2021-08-10  1:05   ` Andrew Lunn
2021-08-10  9:21   ` Florian Fainelli
2021-08-11 13:27   ` Linus Walleij
2021-08-09 11:57 ` [RFC PATCH net-next 4/4] net: dsa: create a helper for locating EtherType DSA headers on TX Vladimir Oltean
2021-08-10  1:07   ` Andrew Lunn
2021-08-10  9:22   ` Florian Fainelli
2021-08-11 13:28   ` Linus Walleij

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