Evgeniy Polyakov wrote:
On Sat, Jun 10, 2006 at 01:42:21PM +0100, Daniel Drake ([EMAIL PROTECTED])
wrote:
Herbert Xu wrote:
Correct. All callers of hard_start_xmit do so under RCU or equivalent
locks so they must be complete by the time synchronize_net() returns.
Does this hold for other operations? Such as:
- The netdev->set_mac_address function
- The wireless ioctl's (SIOCSIWESSID, etc)
Are these also guaranteed to have returned after synchronize_net()?
None of above calls is protected with RCU (except set_mac_address()
called through ioctl, which is performed under read_lock which disables
preemtption), so they still can run after synchronize_net().
But if you are talking about synchronize_net() inside
unregister_netdevice(), which is called from
usbnet_disconnect()->unregister_netdev(), than it is safe.
Are you referring to set_mac_address in the above statement, or both
set_mac_address *and* the wireless ioctls?
I'm basically just looking to clarify that after unregister_netdev has
completed, none of the following can be still in progress on any CPU,
and none of the following can be triggered again:
1. hard_start_xmit handler
2. set_mac_address handler
3. WX ioctls
It's logical that this is the case, but the code doesn't make that very
clear (and would certainly result in many potential ZD1211 races if this
was not the case).
Daniel
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