diff options
| author | John Fastabend <john.r.fastabend@intel.com> | 2010-07-01 17:21:57 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-07-03 08:59:07 +0400 |
| commit | f0796d5c73e59786d09a1e617689d1d415f2db44 (patch) | |
| tree | ecb17c65c5b6a162824a1e11fee24364852837f8 /include/linux/netdevice.h | |
| parent | 4ef6acff83222f4496ceef7d1f0ee9e50a5bb403 (diff) | |
| download | linux-f0796d5c73e59786d09a1e617689d1d415f2db44.tar.xz | |
net: decreasing real_num_tx_queues needs to flush qdisc
Reducing real_num_queues needs to flush the qdisc otherwise
skbs with queue_mappings greater then real_num_tx_queues can
be sent to the underlying driver.
The flow for this is,
dev_queue_xmit()
dev_pick_tx()
skb_tx_hash() => hash using real_num_tx_queues
skb_set_queue_mapping()
...
qdisc_enqueue_root() => enqueue skb on txq from hash
...
dev->real_num_tx_queues -= n
...
sch_direct_xmit()
dev_hard_start_xmit()
ndo_start_xmit(skb,dev) => skb queue set with old hash
skbs are enqueued on the qdisc with skb->queue_mapping set
0 < queue_mappings < real_num_tx_queues. When the driver
decreases real_num_tx_queues skb's may be dequeued from the
qdisc with a queue_mapping greater then real_num_tx_queues.
This fixes a case in ixgbe where this was occurring with DCB
and FCoE. Because the driver is using queue_mapping to map
skbs to tx descriptor rings we can potentially map skbs to
rings that no longer exist.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/netdevice.h')
| -rw-r--r-- | include/linux/netdevice.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 40291f375024..5e6188d9f017 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1656,6 +1656,9 @@ static inline int netif_is_multiqueue(const struct net_device *dev) return (dev->num_tx_queues > 1); } +extern void netif_set_real_num_tx_queues(struct net_device *dev, + unsigned int txq); + /* Use this variant when it is known for sure that it * is executing from hardware interrupt context or with hardware interrupts * disabled. |