Re: [PROPOSED PATCH] ATM refcount + firestream

From: Philipp Rumpf (prumpf@parcelfarce.linux.theplanet.co.uk)
Date: Sat Oct 28 2000 - 10:05:37 EST


On Sat, Oct 28, 2000 at 09:55:21AM -0400, Brian Gerst wrote:
> Yes, but they can be called (and sleep) with module refcount == 0. This
> is because the file descripter used to perform the ioctl isn't directly
> associated with the network device, thereby not incrementing the
> refcount on open.

According to my proposal, it is perfectly safe to call a function in a module
while the module's use count is 0. This function would typically look like this:

foo()
{
        MOD_INC_USE_COUNT;

        copy_*_user() (or anything else that sleeps);
        
        MOD_DEC_USE_COUNT;

        return bar;
}

The only difference to the "old" module scheme is that the above currently isn't
safe on SMP systems.
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