Re: [PATCH] bonding: reset queue mapping prior to transmission to physical device (v5)
From: Jay Vosburgh <hidden>
Date: 2011-06-03 23:31:15
Neil Horman [off-list ref] wrote:
The bonding driver is multiqueue enabled, in which each queue represents a slave to enable optional steering of output frames to given slaves against the default output policy. However, it needs to reset the skb->queue_mapping prior to queuing to the physical device or the physical slave (if it is multiqueue) could wind up transmitting on an unintended tx queue Change Notes: v2) Based on first pass review, updated the patch to restore the origional queue mapping that was found in bond_select_queue, rather than simply resetting to zero. This preserves the value of queue_mapping when it was set on receive in the forwarding case which is desireable. v3) Fixed spelling an casting error in skb->cb v4) fixed to store raw queue_mapping to avoid double decrement v5) Eric D requested that ->cb access be wrapped in a macro.
Shouldn't the change log go below the "---" so it doesn't end up in the git commit log? In any event, I looked for ways into bond_dev_queue_xmit without first passing through bond_select_queue (lest stale cb[] data intrude), and I don't see any, so I think this is ok. Signed-off-by: Jay Vosburgh <redacted> -J
quoted hunk ↗ jump to hunk
Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Jay Vosburgh <redacted> CC: Andy Gospodarek <andy@greyhouse.net> CC: "David S. Miller" <davem@davemloft.net> --- drivers/net/bonding/bond_main.c | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-)diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 17b4dd9..abf6e19 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c@@ -388,6 +388,8 @@ struct vlan_entry *bond_next_vlan(struct bonding *bond, struct vlan_entry *curr)return next; } +#define bond_queue_mapping(skb) (*(u16 *)((skb)->cb)) + /** * bond_dev_queue_xmit - Prepare skb for xmit. *@@ -400,6 +402,9 @@ int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb,{ skb->dev = slave_dev; skb->priority = 1; + + skb->queue_mapping = bond_queue_mapping(skb); + if (unlikely(netpoll_tx_running(slave_dev))) bond_netpoll_send_skb(bond_get_slave_by_dev(bond, slave_dev), skb); else@@ -4206,6 +4211,7 @@ static inline int bond_slave_override(struct bonding *bond,return res; } + static u16 bond_select_queue(struct net_device *dev, struct sk_buff *skb) { /*@@ -4216,6 +4222,11 @@ static u16 bond_select_queue(struct net_device *dev, struct sk_buff *skb)*/ u16 txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0; + /* + * Save the original txq to restore before passing to the driver + */ + bond_queue_mapping(skb) = skb->queue_mapping; + if (unlikely(txq >= dev->real_num_tx_queues)) { do { txq -= dev->real_num_tx_queues; -- 1.7.3.4
--- -Jay Vosburgh, IBM Linux Technology Center, fubar@us.ibm.com