Re: [tip:bkl/drivers] drivers: Remove BKL from misc_open

From: Thomas Gleixner
Date: Wed Oct 14 2009 - 12:18:42 EST


on Wed, 14 Oct 2009, Alan Cox wrote:
> On Wed, 14 Oct 2009 15:47:39 GMT
> tip-bot for Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> > Commit-ID: 40b798efe3460797a4ac928ee2e038774e2758eb
> > Gitweb: http://git.kernel.org/tip/40b798efe3460797a4ac928ee2e038774e2758eb
> > Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > AuthorDate: Sat, 10 Oct 2009 15:35:43 +0000
> > Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > CommitDate: Wed, 14 Oct 2009 17:33:32 +0200
> >
> > drivers: Remove BKL from misc_open
> >
> > misc_open() is already serialized with misc_mtx. Remove the BKL
> > locking which got there via the BKL pushdown.
>
> NAK.
>
> You can't simply assume the mutex is enough - you have to either push it
> down or review *every* possible called point below the lock_kernel take.
>
> In this case the open method of the misc devices below sometimes uses the
> BKL.

The BKL got pushed down into the open methods of misc dev users and we
do not need to take it twice in a row, right ?

Thanks,

tglx

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