Re: [ 33/52] net: Fix issue with netdev_tx_reset_queue not resettingqueue from XOFF state

From: Jonathan Nieder
Date: Thu May 10 2012 - 15:47:14 EST

David Miller wrote:
> From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>

>> All of the changes in igb are unnecessary. I think they can be dropped
>> from the patch as they have already been reverted from the latest
>> net-next. The only change that is really needed is the piece in
>> netdevice.h below.
> Does it hurt? If not, just let it be.

Based on the commit description for dad8a3b3eaa0 ("igb, ixgbe:
netdev_tx_reset_queue incorrectly called from tx init path"), yes, it
hurts. I don't know if it hurts enough to justify holding up this
patch until dad8a3b3eaa0 hits mainline.

| this sort of works in most cases except
| when the number of real tx queues changes. When the number of real
| tx queues changes netdev_tx_reset_queue() only gets called on the
| new number of queues so when we reduce the number of queues we risk
| triggering the watchdog timer and repeated device resets.
| So this is not only a cosmetic issue but causes real bugs. For
| example enabling/disabling DCB or FCoE in ixgbe will trigger this.
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