| Message ID | 20201101191620.589272-12-vladimir.oltean@nxp.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Generic TX reallocation for DSA | expand |
On 11/1/2020 11:16 AM, Vladimir Oltean wrote: > 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 <hauke@hauke-m.de> > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
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;
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 <hauke@hauke-m.de> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> --- Changes in v3: None. Changes in v2: None. net/dsa/tag_gswip.c | 5 ----- 1 file changed, 5 deletions(-)