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Commit 90b602f8 authored by Miroslav Lichvar's avatar Miroslav Lichvar Committed by David S. Miller
Browse files

net: add function to retrieve original skb device using NAPI ID 



Since commit b6858177 ("net: Make skb->skb_iif always track
skb->dev") skbs don't have the original index of the interface which
received the packet. This information is now needed for a new control
message related to hardware timestamping.

Instead of adding a new field to skb, we can find the device by the NAPI
ID if it is available, i.e. CONFIG_NET_RX_BUSY_POLL is enabled and the
driver is using NAPI. Add dev_get_by_napi_id() and also skb_napi_id() to
hide the CONFIG_NET_RX_BUSY_POLL ifdef.

CC: Richard Cochran <richardcochran@gmail.com>
Suggested-by: default avatarWillem de Bruijn <willemb@google.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarMiroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e3412575

include/linux/netdevice.h

+1 −0
Original line number Diff line number Diff line
@@ -2456,6 +2456,7 @@ static inline int dev_recursion_level(void) 
struct net_device *dev_get_by_index(struct net *net, int ifindex);

struct net_device *__dev_get_by_index(struct net *net, int ifindex);

struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex);

struct net_device *dev_get_by_napi_id(unsigned int napi_id);

int netdev_get_name(struct net *net, char *name, int ifindex);

int dev_restart(struct net_device *dev);

int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb);

include/linux/skbuff.h

+9 −0
Original line number Diff line number Diff line
@@ -858,6 +858,15 @@ static inline bool skb_pkt_type_ok(u32 ptype) 
	return ptype <= PACKET_OTHERHOST;

}



static inline unsigned int skb_napi_id(const struct sk_buff *skb)

{

#ifdef CONFIG_NET_RX_BUSY_POLL

	return skb->napi_id;

#else

	return 0;

#endif

}



void kfree_skb(struct sk_buff *skb);

void kfree_skb_list(struct sk_buff *segs);

void skb_tx_error(struct sk_buff *skb);

net/core/dev.c

+26 −0
Original line number Diff line number Diff line
@@ -163,6 +163,7 @@ static int netif_rx_internal(struct sk_buff *skb); 
static int call_netdevice_notifiers_info(unsigned long val,

					 struct net_device *dev,

					 struct netdev_notifier_info *info);

static struct napi_struct *napi_by_id(unsigned int napi_id);



/*

 * The @dev_base_head list is protected by @dev_base_lock and the rtnl
@@ -866,6 +867,31 @@ struct net_device *dev_get_by_index(struct net *net, int ifindex) 
}

EXPORT_SYMBOL(dev_get_by_index);



/**

 *	dev_get_by_napi_id - find a device by napi_id

 *	@napi_id: ID of the NAPI struct

 *

 *	Search for an interface by NAPI ID. Returns %NULL if the device

 *	is not found or a pointer to the device. The device has not had

 *	its reference counter increased so the caller must be careful

 *	about locking. The caller must hold RCU lock.

 */



struct net_device *dev_get_by_napi_id(unsigned int napi_id)

{

	struct napi_struct *napi;



	WARN_ON_ONCE(!rcu_read_lock_held());



	if (napi_id < MIN_NAPI_ID)

		return NULL;



	napi = napi_by_id(napi_id);



	return napi ? napi->dev : NULL;

}

EXPORT_SYMBOL(dev_get_by_napi_id);



/**

 *	netdev_get_name - get a netdevice name, knowing its ifindex.

 *	@net: network namespace