Re: [PATCH 5/6] procfs: Push down the bkl from ioctl

From: Arnd Bergmann
Date: Tue Mar 30 2010 - 14:54:34 EST


On Tuesday 30 March 2010 20:27:12 Frederic Weisbecker wrote:
> On Tue, Mar 30, 2010 at 11:37:27AM +0100, Arnd Bergmann wrote:
> > On Tuesday 30 March 2010, Frederic Weisbecker wrote:
> > > Push down the bkl from procfs's ioctl main handler to its users.
> > > Only three procfs users implement an ioctl (non unlocked) handler.
> > > Turn them into unlocked_ioctl and push down the Devil inside.
> >
> > Looks good to me. I would have used a single unlock and return statement
> > in i8k_ioctl and isdn_divert_ioctl, with goto instead of adding an
> > unlock to each return, but it doesn't matter much.
>
>
> I did that first, but actually that didn't make much difference:
>
> ret = foo; unlock_kernel()
> goto end; VS return foo;

Yes, the amount of code needed is comparable, but it is much easier
to validate that you did not miss an unlock when you know that there
is a single return statement in the function. It also helps the next
person that may want to replace the BKL with a different lock.

Arnd
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