[PATCH net-next 0/3] net: dsa: Move padding into Broadcom tagger

[PATCH net-next 0/3] net: dsa: Move padding into Broadcom tagger

[Florian Fainelli]

Hi all,

This patch series moves the padding of short packets to where it belongs
within the DSA Broadcom tagger code, I just found myself doing this for
a third driver, which was a clear indication this was wrong and did not
scale.

Florian Fainelli (3):
  net: dsa: Move padding into Broadcom tagger
  net: systemport: Remove short packet padding
  net: bgmac: Remove short packet padding for DSA

 drivers/net/ethernet/broadcom/bcmsysport.c | 12 ------------
 drivers/net/ethernet/broadcom/bgmac.c      | 15 ---------------
 net/dsa/tag_brcm.c                         | 12 ++++++++++++
 3 files changed, 12 insertions(+), 27 deletions(-)

-- 
2.14.1

[PATCH net-next 1/3] net: dsa: Move padding into Broadcom tagger

[Florian Fainelli]

Instead of having the different master network device drivers
potentially used by DSA/Broadcom tags, move the padding necessary for
the switches to accept short packets where it makes most sense: within
tag_brcm.c. This avoids multiplying the number of similar commits to
e.g: bgmac, bcmsysport, etc.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 net/dsa/tag_brcm.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
index e6e0b7b6025c..2b06bb91318b 100644
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -70,6 +70,18 @@ static struct sk_buff *brcm_tag_xmit_ll(struct sk_buff *skb,
 	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
+	 * need to make sure that packets are at least 68 bytes
+	 * (including FCS and tag) because the length verification is done after
+	 * the Broadcom tag is stripped off the ingress packet.
+	 *
+	 * Let dsa_slave_xmit() free the SKB
+	 */
+	if (__skb_put_padto(skb, ETH_ZLEN + BRCM_TAG_LEN, false))
+		return NULL;
+
 	skb_push(skb, BRCM_TAG_LEN);
 
 	if (offset)
-- 
2.14.1

[PATCH net-next 2/3] net: systemport: Remove short packet padding

[Florian Fainelli]

Short packet padding added to the driver is only necessary when using
Broadcom tags, but since this is now taken care of net/dsa/tag_brcm.c,
we are guaranteed being given correctly padded packets.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/ethernet/broadcom/bcmsysport.c | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index 087f01b4dc3a..f15a8fc6dfc9 100644
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -1216,18 +1216,6 @@ static netdev_tx_t bcm_sysport_xmit(struct sk_buff *skb,
 		goto out;
 	}
 
-	/* 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
-	 * need to make sure that packets are at least 68 bytes
-	 * (including FCS and tag) because the length verification is done after
-	 * the Broadcom tag is stripped off the ingress packet.
-	 */
-	if (skb_put_padto(skb, ETH_ZLEN + ENET_BRCM_TAG_LEN)) {
-		ret = NETDEV_TX_OK;
-		goto out;
-	}
-
 	/* Insert TSB and checksum infos */
 	if (priv->tsb_en) {
 		skb = bcm_sysport_insert_tsb(skb, dev);
-- 
2.14.1

[PATCH net-next 3/3] net: bgmac: Remove short packet padding for DSA

[Florian Fainelli]

DSA now correctly pads short packets within net/dsa/tag_brcm.c such that
this it is no longer necessary to do this within bgmac.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/ethernet/broadcom/bgmac.c | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index 1d96cd594ade..8eef9fb6b1fe 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -128,8 +128,6 @@ bgmac_dma_tx_add_buf(struct bgmac *bgmac, struct bgmac_dma_ring *ring,
 	dma_desc->ctl1 = cpu_to_le32(ctl1);
 }
 
-#define ENET_BRCM_TAG_LEN	4
-
 static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
 				    struct bgmac_dma_ring *ring,
 				    struct sk_buff *skb)
@@ -142,18 +140,6 @@ static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
 	u32 flags;
 	int i;
 
-	/* 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
-	 * need to make sure that packets are at least 68 bytes
-	 * (including FCS and tag) because the length verification is done after
-	 * the Broadcom tag is stripped off the ingress packet.
-	 */
-	if (netdev_uses_dsa(net_dev)) {
-		if (skb_put_padto(skb, ETH_ZLEN + ENET_BRCM_TAG_LEN))
-			goto err_stats;
-	}
-
 	if (skb->len > BGMAC_DESC_CTL1_LEN) {
 		netdev_err(bgmac->net_dev, "Too long skb (%d)\n", skb->len);
 		goto err_drop;
@@ -240,7 +226,6 @@ static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
 
 err_drop:
 	dev_kfree_skb(skb);
-err_stats:
 	net_dev->stats.tx_dropped++;
 	net_dev->stats.tx_errors++;
 	return NETDEV_TX_OK;
-- 
2.14.1

Re: [PATCH net-next 0/3] net: dsa: Move padding into Broadcom tagger

[Andrew Lunn]

On Wed, Jan 03, 2018 at 10:12:59PM -0800, Florian Fainelli wrote:
> Hi all,
> 
> This patch series moves the padding of short packets to where it belongs
> within the DSA Broadcom tagger code, I just found myself doing this for
> a third driver, which was a clear indication this was wrong and did not
> scale.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH net-next 0/3] net: dsa: Move padding into Broadcom tagger

[David Miller]

From: Florian Fainelli <f.fainelli@gmail.com>
Date: Wed,  3 Jan 2018 22:12:59 -0800

> This patch series moves the padding of short packets to where it belongs
> within the DSA Broadcom tagger code, I just found myself doing this for
> a third driver, which was a clear indication this was wrong and did not
> scale.

Series applied, thanks Florian.