linux/include
John Fastabend f0796d5c73 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>
2010-07-02 21:59:07 -07:00
..
acpi Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2010-05-28 14:42:18 -07:00
asm-generic numa: introduce numa_mem_id()- effective local memory node id 2010-05-27 09:12:57 -07:00
crypto crypto: skcipher - Add ablkcipher_walk interfaces 2010-05-19 14:13:07 +10:00
drm Merge branch 'drm-for-2.6.35' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-05-21 11:14:52 -07:00
keys
linux net: decreasing real_num_tx_queues needs to flush qdisc 2010-07-02 21:59:07 -07:00
math-emu
media V4L/DVB: v4l2-subdev.h: Add support for enum_dv_preset 2010-05-19 12:59:01 -03:00
mtd
net net: decreasing real_num_tx_queues needs to flush qdisc 2010-07-02 21:59:07 -07:00
pcmcia pcmcia: remove unused mem_op.h 2010-05-10 10:23:20 +02:00
rdma IB/core: Allow device-specific per-port sysfs files 2010-05-21 10:34:44 -07:00
rxrpc
scsi [SCSI] libfc: Move the port_id into lport 2010-05-16 22:22:34 -04:00
sound Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6 2010-05-20 09:41:44 -07:00
trace drop unused dentry argument to ->fsync 2010-05-27 22:05:02 -04:00
video fbdev: move FBIO_WAITFORVSYNC to linux/fb.h 2010-05-25 08:07:09 -07:00
xen
Kbuild