Re: [PATCH 2.5.68] eliminate deprecated MOD_INC_USE_COUNT/MOD_DEC_USE_COUNT in md.c

[Paul Clements <Paul.Clements@SteelEye.com>]

Neil Brown wrote:
> On Tuesday April 22, Paul.Clements@SteelEye.com wrote:
> > Following is a simple patch to remove deprecated MOD_INC_USE_COUNT from
> > md.c.
> >
> > If it looks good, please apply.
> 
> I don't think it is that easy.

Well, I think that it's safe to remove the MOD_INC_USE_COUNT...here's
why:

We're protected while a device is open (by the infrastructure in the
block layer that takes a module reference when an md device is opened
and keeps it until the device is closed).

So, while any ioctl is being done, there's an md device open...and...the
ioctls are currently the only way to activate md devices (autorun,
RUN_ARRAY, etc.). 

Now, none of these ioctls will succeed (activate a device) unless there
is an underlying raid personality module (raid0, raid1, et al.) for the
array already loaded. The underlying raid modules also take module
references against md, so by the time a device is activated, md is
already pinned into memory...

So we're safe from every angle...the MOD_INC_USE_COUNT/MOD_DEC_USE_COUNT
appears to have been superfluous in the first place...(at least with the
way 2.5 kernel module refs work)

--
Paul