netpoll: Respect NETIF_F_LLTX

Stop taking the transmit lock when a network device has specified
NETIF_F_LLTX.

If no locks needed to trasnmit a packet this is the ideal scenario for
netpoll as all packets can be trasnmitted immediately.

Even if some locks are needed in ndo_start_xmit skipping any unnecessary
serialization is desirable for netpoll as it makes it more likely a
debugging packet may be trasnmitted immediately instead of being
deferred until later.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric W. Biederman
2014-03-27 15:42:20 -07:00
committed by David S. Miller
parent 080b3c19a4
commit 5efeac44cf
2 changed files with 10 additions and 5 deletions

View File

@@ -2909,6 +2909,11 @@ static inline void netif_tx_unlock_bh(struct net_device *dev)
} \
}
#define HARD_TX_TRYLOCK(dev, txq) \
(((dev->features & NETIF_F_LLTX) == 0) ? \
__netif_tx_trylock(txq) : \
true )
#define HARD_TX_UNLOCK(dev, txq) { \
if ((dev->features & NETIF_F_LLTX) == 0) { \
__netif_tx_unlock(txq); \