On Tue, 2005-01-25 at 22:42 +0000, Christoph Hellwig wrote: > > Zeroing can be found easily - the whole structure is NULL pointer, > > and will always panic if accessed(from running superio code), > > but redzoning is only happen on borders, > > and can catch writes over the boards, which is rarely in this case. > > As I mentioned the redzoning was a brainfar on my side. Slab debug > code memsets all code with an easily recognizable pattern (which 0 is _NOT_). > > So this is totally useless, please don't do it - as all major subsystems > don't do it either.
Ok, I do not insist.
> > Each superio chip is registered with superio core without any devices.
> > Each logical device is registered with superio core without any superio
> > chip.
> >
> > Then core checks if some chip is found in some superio device, and
> > links
> > it to appropriate device.
> > So if board has several superio chips(like soekris board) and several
> > logical devices in it, then we only have 2 superio small drivers, and
> > several
> > logical device drivers, but not
> > number_of_superio_chips*number_of_logical_devices drivers.
>
> That's how just about any bus driver works so far.
>
> Now somewhere else in the thread I read the a single logical device
> might belong to multiple superio devices. Which is kinda odd, but in
> that case it's indeed needed.
>
> So please add a big comment explaining that properperty because it
> is extemly uncommon, and make 'ptr' in the chain structure typed
> instead of void *
Ok.
> > Yes, and it is better than removing module whose structures are in use.
> > SuperIO core is asynchronous in it's nature, one can use logical device
> > through superio core and remove it's module on other CPU, above loop
> > will
> > wait untill all reference counters are dropped.
>
> General rule is: increment module reference count while the hardware
> is actually in use, and let device structures be allocated by the
> bus core so drivers can be freed with them still allocated. That's
> how the driver model and thus about every other subsystem works.
It is not general rule - network stack does not have such mechanism,
which is
very good, I doubt each block device module increment it's module
reference
when it catch a request...
It is internal structure that has reference counter, not module itself,
and this
structure may be in use, when module is unloaded, thus unloading must
wait,
untill all it's structures are freed.
--
Evgeniy Polyakov
Crash is better than data corruption -- Arthur Grabowski
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