From b68b0dd0fb2d91056d5241a19960cf47d4a80f05 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sun, 5 May 2019 13:19:24 +0300 Subject: [PATCH] net: dsa: Keep private info in the skb->cb Map a DSA structure over the 48-byte control block that will hold skb info on transmit and receive. This is only for use within the DSA processing layer (e.g. communicating between DSA core and tagger) and not for passing info around with other layers such as the master net device. Also add a DSA_SKB_CB_PRIV() macro which retrieves a pointer to the space up to 48 bytes that the DSA structure does not use. This space can be used for drivers to add their own private info. One use is for the PTP timestamping code path. When cloning a skb, annotate the original with a pointer to the clone, which the driver can then find easily and place the timestamp to. This avoids the need of a separate queue to hold clones and a way to match an original to a cloned skb. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- include/net/dsa.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/include/net/dsa.h b/include/net/dsa.h index c90ceeec7d1f..d628587e0bde 100644 --- a/include/net/dsa.h +++ b/include/net/dsa.h @@ -83,6 +83,37 @@ struct dsa_device_ops { #define MODULE_ALIAS_DSA_TAG_DRIVER(__proto) \ MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __stringify(__proto##_VALUE)) +struct dsa_skb_cb { + struct sk_buff *clone; +}; + +struct __dsa_skb_cb { + struct dsa_skb_cb cb; + u8 priv[48 - sizeof(struct dsa_skb_cb)]; +}; + +#define __DSA_SKB_CB(skb) ((struct __dsa_skb_cb *)((skb)->cb)) + +#define DSA_SKB_CB(skb) ((struct dsa_skb_cb *)((skb)->cb)) + +#define DSA_SKB_CB_COPY(nskb, skb) \ + { *__DSA_SKB_CB(nskb) = *__DSA_SKB_CB(skb); } + +#define DSA_SKB_CB_ZERO(skb) \ + { *__DSA_SKB_CB(skb) = (struct __dsa_skb_cb) {0}; } + +#define DSA_SKB_CB_PRIV(skb) \ + ((void *)(skb)->cb + offsetof(struct __dsa_skb_cb, priv)) + +#define DSA_SKB_CB_CLONE(_clone, _skb) \ + { \ + struct sk_buff *clone = _clone; \ + struct sk_buff *skb = _skb; \ + \ + DSA_SKB_CB_COPY(clone, skb); \ + DSA_SKB_CB(skb)->clone = clone; \ + } + struct dsa_switch_tree { struct list_head list;