Messages in this thread | | | Subject | Re: [1/1] connector/CBUS: new messaging subsystem. Revision number next. | From | Evgeniy Polyakov <> | Date | Wed, 27 Apr 2005 09:32:06 +0400 |
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On Wed, 2005-04-27 at 00:16 -0500, Dmitry Torokhov wrote: > On Tuesday 26 April 2005 23:06, Evgeniy Polyakov wrote: > > Let's clarify that we are talking about userspace->kernelspace > > direction. > > Only for that messages callback path is invoked. > > What about kernelspace->userspace or kernelspace->kernelspace? > From what I see nothing stops kernel code from calling cn_netlink_send, > in fact your cbus does exactly that. So I am confused why you singled > out userspace->kernelspace direction.
You miunderstand the code - cn_netlink_send() never ends up in callback invocation, it can only deliver messages in kernelspace->userspace direction. kernelspace->userspace direction ends up adding buffer into socket queue, from which userspace may read data using recv() system call. There is no kernelspace->kernelspace sending possibility except by creating new socket in userspace and sendmsg/recvmsg interception/using, but that is the same as reading from userspace.
-- Evgeniy Polyakov
Crash is better than data corruption -- Arthur Grabowski [unhandled content-type:application/pgp-signature] | |