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Commit e79d8429 authored by Rusty Russell's avatar Rusty Russell Committed by David S. Miller
Browse files

netdevice: document NETDEV_TX_BUSY deprecation. 

This paraphrases DaveM (and steals some of his words) explaining why
a device shouldn't return NETDEV_TX_BUSY, even though it looks so inviting
to driver authors.

See http://www.spinics.net/lists/netdev/msg322350.html



Inspired-by: default avatarDavid Miller <davem@davemloft.net>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0bd66827

include/linux/netdevice.h

+4 −1
Original line number Original line Diff line number Diff line
@@ -795,7 +795,10 @@ typedef u16 (*select_queue_fallback_t)(struct net_device *dev, 
 * netdev_tx_t (*ndo_start_xmit)(struct sk_buff *skb,

 * netdev_tx_t (*ndo_start_xmit)(struct sk_buff *skb,

 *                               struct net_device *dev);

 *                               struct net_device *dev);

 *	Called when a packet needs to be transmitted.

 *	Called when a packet needs to be transmitted.

 *	Must return NETDEV_TX_OK , NETDEV_TX_BUSY.

 *	Returns NETDEV_TX_OK.  Can return NETDEV_TX_BUSY, but you should stop

 *	the queue before that can happen; it's for obsolete devices and weird

 *	corner cases, but the stack really does a non-trivial amount

 *	of useless work if you return NETDEV_TX_BUSY.

 *        (can also return NETDEV_TX_LOCKED iff NETIF_F_LLTX)

 *        (can also return NETDEV_TX_LOCKED iff NETIF_F_LLTX)

 *	Required can not be NULL.

 *	Required can not be NULL.

 *

 *