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Commit c578e9ab authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'netdev_tx_locked-removal' 



Florian Westphal says:

====================
net: core: remove TX_LOCKED support

Not that many users left, lets kill it.

TX_LOCKED was meant to be used by LLTX drivers when spin_trylock()
failed.  Stack then re-queued if collisions happened on different
cpus or free'd the skb to prevent deadlocks.

Most of the driver removal patches fall into one of three categories:
1. remove the driver-private tx lock (and LLTX flag), or...
2. convert spin_trylock to plain spin_lock, or...
3. convert TX_LOCKED to free+TX_OK

Patches are grouped by these categories, last patch is the actual removal.
All driver changes were compile tested only with exception of atl1e.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents c971c0e5 f0cdf76c

Documentation/networking/netdev-features.txt

+4 −6
Original line number Diff line number Diff line
@@ -131,13 +131,11 @@ stack. Driver should not change behaviour based on them. 


 * LLTX driver (deprecated for hardware drivers)



NETIF_F_LLTX should be set in drivers that implement their own locking in

transmit path or don't need locking at all (e.g. software tunnels).

In ndo_start_xmit, it is recommended to use a try_lock and return

NETDEV_TX_LOCKED when the spin lock fails.  The locking should also properly

protect against other callbacks (the rules you need to find out).

NETIF_F_LLTX is meant to be used by drivers that don't need locking at all,

e.g. software tunnels.



Don't use it for new drivers.

This is also used in a few legacy drivers that implement their

own locking, don't use it for new (hardware) drivers.



 * netns-local device

Documentation/networking/netdevices.txt

+3 −6
Original line number Diff line number Diff line
@@ -69,10 +69,9 @@ ndo_start_xmit: 


	When the driver sets NETIF_F_LLTX in dev->features this will be

	called without holding netif_tx_lock. In this case the driver

	has to lock by itself when needed. It is recommended to use a try lock

	for this and return NETDEV_TX_LOCKED when the spin lock fails.

	has to lock by itself when needed.

	The locking there should also properly protect against

	set_rx_mode. Note that the use of NETIF_F_LLTX is deprecated.

	set_rx_mode. WARNING: use of NETIF_F_LLTX is deprecated.

	Don't use it for new drivers.



	Context: Process with BHs disabled or BH (timer),
@@ -83,8 +82,6 @@ ndo_start_xmit: 
	o NETDEV_TX_BUSY Cannot transmit packet, try later 

	  Usually a bug, means queue start/stop flow control is broken in

	  the driver. Note: the driver must NOT put the skb in its DMA ring.

	o NETDEV_TX_LOCKED Locking failed, please retry quickly.

	  Only valid when NETIF_F_LLTX is set.



ndo_tx_timeout:

	Synchronization: netif_tx_lock spinlock; all TX queues frozen.

drivers/infiniband/hw/nes/nes_nic.c

+5 −8
Original line number Diff line number Diff line
@@ -356,7 +356,7 @@ static int nes_netdev_stop(struct net_device *netdev) 
/**

 * nes_nic_send

 */

static int nes_nic_send(struct sk_buff *skb, struct net_device *netdev)

static bool nes_nic_send(struct sk_buff *skb, struct net_device *netdev)

{

	struct nes_vnic *nesvnic = netdev_priv(netdev);

	struct nes_device *nesdev = nesvnic->nesdev;
@@ -413,7 +413,7 @@ static int nes_nic_send(struct sk_buff *skb, struct net_device *netdev) 
					netdev->name, skb_shinfo(skb)->nr_frags + 2, skb_headlen(skb));

			kfree_skb(skb);

			nesvnic->tx_sw_dropped++;

			return NETDEV_TX_LOCKED;

			return false;

		}

		set_bit(nesnic->sq_head, nesnic->first_frag_overflow);

		bus_address = pci_map_single(nesdev->pcidev, skb->data + NES_FIRST_FRAG_SIZE,
@@ -454,8 +454,7 @@ static int nes_nic_send(struct sk_buff *skb, struct net_device *netdev) 
	set_wqe_32bit_value(nic_sqe->wqe_words, NES_NIC_SQ_WQE_MISC_IDX, wqe_misc);

	nesnic->sq_head++;

	nesnic->sq_head &= nesnic->sq_size - 1;



	return NETDEV_TX_OK;

	return true;

}
@@ -673,13 +672,11 @@ static int nes_netdev_start_xmit(struct sk_buff *skb, struct net_device *netdev) 
			skb_linearize(skb);

			skb_set_transport_header(skb, hoffset);

			skb_set_network_header(skb, nhoffset);

			send_rc = nes_nic_send(skb, netdev);

			if (send_rc != NETDEV_TX_OK)

			if (!nes_nic_send(skb, netdev))

				return NETDEV_TX_OK;

		}

	} else {

		send_rc = nes_nic_send(skb, netdev);

		if (send_rc != NETDEV_TX_OK)

		if (!nes_nic_send(skb, netdev))

			return NETDEV_TX_OK;

	}

drivers/net/ethernet/amd/7990.c

+5 −3
Original line number Diff line number Diff line
@@ -543,11 +543,13 @@ int lance_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	static int outs;

	unsigned long flags;



	if (!TX_BUFFS_AVAIL)

		return NETDEV_TX_LOCKED;



	netif_stop_queue(dev);



	if (!TX_BUFFS_AVAIL) {

		dev_consume_skb_any(skb);

		return NETDEV_TX_OK;

	}



	skblen = skb->len;



#ifdef DEBUG_DRIVER

drivers/net/ethernet/amd/a2065.c

+3 −4
Original line number Diff line number Diff line
@@ -547,10 +547,8 @@ static netdev_tx_t lance_start_xmit(struct sk_buff *skb, 


	local_irq_save(flags);



	if (!lance_tx_buffs_avail(lp)) {

		local_irq_restore(flags);

		return NETDEV_TX_LOCKED;

	}

	if (!lance_tx_buffs_avail(lp))

		goto out_free;



#ifdef DEBUG

	/* dump the packet */
@@ -573,6 +571,7 @@ static netdev_tx_t lance_start_xmit(struct sk_buff *skb, 


	/* Kick the lance: transmit now */

	ll->rdp = LE_C0_INEA | LE_C0_TDMD;

 out_free:

	dev_kfree_skb(skb);



	local_irq_restore(flags);