A compendium of questions and misc stuff concerning hotplug:
- Is everyone happy with call_usermodehelper() being asynchronous? It
_could_ be given a `synchronous' option, but that's a fair bit of
obfuscation and it does expose us to deadlocks if the caller has any
semaphores held.
- One person who definitely needs synchronous semantics is
drivers/net/hamradio/baycom_epp.c. The poor thing is currently doing
the kernel_thread()/waitpid() stuff itself. So there's a datum.
hmm.. It's running a usermode app with the rtnl lock held.
There's a counter-datum.
- The three USB netdevice drivers look a bit racey in the probe()
function. Some can be fixed inline, but it may be better to just
call dev_probe_lock()/dev_probe_unlock() in
usb_find_interface_driver(). That's if dev_probe_lock() makes its
way to kernel.org...
- On the unregister/removal path, the netdevice layer ensures that
the interface is removed from the kernel namespace prior to launching
`/sbin/hotplug net unregister eth0'.
This means that when handling netdevice unregistration
/sbin/hotplug cannot and must not attempt to do anything with eth0!
Generally it'll fail to find an interface with this name. If it does
find eth0, it'll be the wrong one due to a race.
- I don't think we can say that the kernel hotplug interface is
complete until we have real, working, tested userspace tools. David,
could you please summarise the state of play here? In particular,
what still needs to be done?
-
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This archive was generated by hypermail 2b29 : Fri Dec 15 2000 - 21:00:19 EST