linux-kernel - Re: [patch 4/5] mtd: Remove BKL and convert to unlocked

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Date:	Tue, 20 Oct 2009 07:27:38 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Artem Bityutskiy <dedekind1@...il.com>
cc:	LKML <linux-kernel@...r.kernel.org>,
	ALan Cox <alan@...rguk.ukuu.org.uk>,
	Arnd Bergmann <arnd@...db.de>,
	David Woodhouse <dwmw2@...radead.org>,
	linux-mtd@...ts.infradead.org
Subject: Re: [patch 4/5] mtd: Remove BKL and convert to unlocked_ioctl

On Fri, 16 Oct 2009, Artem Bityutskiy wrote:
> On Thu, 2009-10-15 at 20:28 +0000, Thomas Gleixner wrote:
> > plain text document attachment
> > (mtd-remove-bkl-and-convert-to-unlocked-ioctl.patch)
> > mtd_open() got lock/unlock kernel from the big BKL push down, but it
> > never relied on the BKL serialization as get_mtd_device() takes care
> > of serialization vs. device init/teardown.
> > 
> > mtd_ioctl() is safe w/o the BKL as well. The data which is copied from
> > the mtd data structure is either set up during device initialization
> > or statistics which have never been protected by the BKL against
> > concurrent modification. The mtd functions which are called from
> > various ioctl commands are safe as well.
> > 
> > Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> > Cc: David Woodhouse <dwmw2@...radead.org>
> > Cc: linux-mtd@...ts.infradead.org
> > ---
> >  drivers/mtd/mtdchar.c |   30 ++++++++----------------------
> >  1 file changed, 8 insertions(+), 22 deletions(-)
> 
> [dedekind@eru l2-mtd-2.6.git]$ make -j8
>   CHK     include/linux/version.h
>   CHK     include/linux/utsrelease.h
>   SYMLINK include/asm -> include/asm-x86
>   CALL    scripts/checksyscalls.sh
>   CHK     include/linux/compile.h
>   CC [M]  drivers/mtd/mtdchar.o
> drivers/mtd/mtdchar.c: In function ‘mtd_compat_ioctl’:
> drivers/mtd/mtdchar.c:865: warning: passing argument 1 of ‘mtd_ioctl’ from incompatible pointer type
> drivers/mtd/mtdchar.c:444: note: expected ‘struct file *’ but argument is of type ‘struct inode *’
> drivers/mtd/mtdchar.c:865: warning: passing argument 2 of ‘mtd_ioctl’ makes integer from pointer without a cast
> drivers/mtd/mtdchar.c:444: note: expected ‘u_int’ but argument is of type ‘struct file *’
> drivers/mtd/mtdchar.c:865: error: too many arguments to function ‘mtd_ioctl’

Yeah, found and fixed that already.

      tglx