Message ID | 1247304161.30647.83.camel@johannes.local |
---|---|
State | RFC, archived |
Delegated to: | David Miller |
Headers | show |
Johannes Berg <johannes@sipsolutions.net> writes: > From: Johannes Berg <johannes@sipsolutions.net> > Subject: explain netns notifiers a little better > > Eric explained this to me -- and afterwards the comment > made sense, but not before. Add the the critical point > about interfaces having to be gone from the netns before > subsys notifiers are called. > > Signed-off-by: Johannes Berg <johannes@sipsolutions.net> > --- > include/net/net_namespace.h | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > --- wireless-testing.orig/include/net/net_namespace.h 2009-07-11 11:18:20.000000000 +0200 > +++ wireless-testing/include/net/net_namespace.h 2009-07-11 11:20:49.000000000 +0200 > @@ -239,13 +239,15 @@ struct pernet_operations { > * needs per network namespace operations use device pernet operations, > * otherwise use pernet subsys operations. > * > - * This is critically important. Most of the network code cleanup > - * runs with the assumption that dev_remove_pack has been called so no > - * new packets will arrive during and after the cleanup functions have > - * been called. dev_remove_pack is not per namespace so instead the > - * guarantee of no more packets arriving in a network namespace is > - * provided by ensuring that all network devices and all sockets have > - * left the network namespace before the cleanup methods are called. > + * Network interfaces need to be removed from a dying netns _before_ > + * subsys notifiers can be called, as most of the network code cleanup > + * (which is done from subsys notifiers) runs with the assumption that > + * dev_remove_pack has been called so no new packets will arrive during > + * and after the cleanup functions have been called. dev_remove_pack > + * is not per namespace so instead the guarantee of no more packets > + * arriving in a network namespace is provided by ensuring that all > + * network devices and all sockets have left the network namespace > + * before the cleanup methods are called. > * > * For the longest time the ipv4 icmp code was registered as a pernet > * device which caused kernel oops, and panics during network That seems like a reasonable cleanup to the wording. Eric -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- wireless-testing.orig/include/net/net_namespace.h 2009-07-11 11:18:20.000000000 +0200 +++ wireless-testing/include/net/net_namespace.h 2009-07-11 11:20:49.000000000 +0200 @@ -239,13 +239,15 @@ struct pernet_operations { * needs per network namespace operations use device pernet operations, * otherwise use pernet subsys operations. * - * This is critically important. Most of the network code cleanup - * runs with the assumption that dev_remove_pack has been called so no - * new packets will arrive during and after the cleanup functions have - * been called. dev_remove_pack is not per namespace so instead the - * guarantee of no more packets arriving in a network namespace is - * provided by ensuring that all network devices and all sockets have - * left the network namespace before the cleanup methods are called. + * Network interfaces need to be removed from a dying netns _before_ + * subsys notifiers can be called, as most of the network code cleanup + * (which is done from subsys notifiers) runs with the assumption that + * dev_remove_pack has been called so no new packets will arrive during + * and after the cleanup functions have been called. dev_remove_pack + * is not per namespace so instead the guarantee of no more packets + * arriving in a network namespace is provided by ensuring that all + * network devices and all sockets have left the network namespace + * before the cleanup methods are called. * * For the longest time the ipv4 icmp code was registered as a pernet * device which caused kernel oops, and panics during network