From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754182Ab0CGMka (ORCPT ); Sun, 7 Mar 2010 07:40:30 -0500 Received: from mail-ww0-f46.google.com ([74.125.82.46]:49801 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753576Ab0CGMk2 convert rfc822-to-8bit (ORCPT ); Sun, 7 Mar 2010 07:40:28 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=geo+MroWJHhsATPMLKxQJTLuT0H9olkZXZHB7VcF4jFDAkL0ggFnma5m6LnL9CB+EA G9FDYCbs4IcX+XquL4xs5+a1MlNBn5n3bFbg1TCcW8puaG/eNeHdY3PmnLFMXPq5rNgE 5s+iU4Ia+q5xJ5kq341V6wgfy1ZaudSwmWjbk= MIME-Version: 1.0 In-Reply-To: <20091015083933.815963538@linutronix.de> References: <20091015083906.716130653@linutronix.de> <20091015083933.815963538@linutronix.de> Date: Sun, 7 Mar 2010 13:40:27 +0100 X-Google-Sender-Auth: 2661c5837bff02e1 Message-ID: <10f740e81003070440q3697c089o72ff9f3abcf9d293@mail.gmail.com> Subject: Re: [patch 2/7] m68k: Remove BKL from rtc implementations From: Geert Uytterhoeven To: Thomas Gleixner Cc: LKML , Ingo Molnar , Arnd Bergmann , ALan Cox , Frederic Weisbecker Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 15, 2009 at 09:42, Thomas Gleixner wrote: > m68k does not support SMP. The access to the rtc is already serialized > with local_irq_save/restore which is sufficient on UP. > > The open() protection in arch/m68k/mvme16x/rtc.c is not pretty but > sufficient on UP and safe w/o the BKL. > > open() in arch/m68k/bvme6000/rtc.c can do with the same atomic logic > as arch/m68k/mvme16x/rtc.c Thx, applied. > Signed-off-by: Thomas Gleixner > Cc: Geert Uytterhoeven > --- >  arch/m68k/bvme6000/rtc.c |   29 +++++++++-------------------- >  arch/m68k/mvme16x/rtc.c  |   19 +++++-------------- >  2 files changed, 14 insertions(+), 34 deletions(-) > > Index: linux-2.6-tip/arch/m68k/bvme6000/rtc.c > =================================================================== > --- linux-2.6-tip.orig/arch/m68k/bvme6000/rtc.c > +++ linux-2.6-tip/arch/m68k/bvme6000/rtc.c > @@ -10,7 +10,6 @@ >  #include >  #include >  #include > -#include >  #include >  #include >  #include > @@ -36,10 +35,9 @@ >  static unsigned char days_in_mo[] = >  {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; > > -static char rtc_status; > +static atomic_t rtc_status = ATOMIC_INIT(1); > > -static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, > -                    unsigned long arg) > +static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) >  { >        volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE; >        unsigned char msr; > @@ -133,29 +131,20 @@ static int rtc_ioctl(struct inode *inode >  } > >  /* > - *     We enforce only one user at a time here with the open/close. > - *     Also clear the previous interrupt data on an open, and clean > - *     up things on a close. > + * We enforce only one user at a time here with the open/close. >  */ > - >  static int rtc_open(struct inode *inode, struct file *file) >  { > -       lock_kernel(); > -       if(rtc_status) { > -               unlock_kernel(); > +       if (!atomic_dec_and_test(&rtc_status)) { > +               atomic_inc(&rtc_status); >                return -EBUSY; >        } > - > -       rtc_status = 1; > -       unlock_kernel(); >        return 0; >  } > >  static int rtc_release(struct inode *inode, struct file *file) >  { > -       lock_kernel(); > -       rtc_status = 0; > -       unlock_kernel(); > +       atomic_inc(&rtc_status); >        return 0; >  } > > @@ -164,9 +153,9 @@ static int rtc_release(struct inode *ino >  */ > >  static const struct file_operations rtc_fops = { > -       .ioctl =        rtc_ioctl, > -       .open =         rtc_open, > -       .release =      rtc_release, > +       .unlocked_ioctl = rtc_ioctl, > +       .open           = rtc_open, > +       .release        = rtc_release, >  }; > >  static struct miscdevice rtc_dev = { > Index: linux-2.6-tip/arch/m68k/mvme16x/rtc.c > =================================================================== > --- linux-2.6-tip.orig/arch/m68k/mvme16x/rtc.c > +++ linux-2.6-tip/arch/m68k/mvme16x/rtc.c > @@ -10,7 +10,6 @@ >  #include >  #include >  #include > -#include >  #include >  #include >  #include > @@ -37,8 +36,7 @@ static const unsigned char days_in_mo[] > >  static atomic_t rtc_ready = ATOMIC_INIT(1); > > -static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, > -                    unsigned long arg) > +static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) >  { >        volatile MK48T08ptr_t rtc = (MK48T08ptr_t)MVME_RTC_BASE; >        unsigned long flags; > @@ -121,22 +119,15 @@ static int rtc_ioctl(struct inode *inode >  } > >  /* > - *     We enforce only one user at a time here with the open/close. > - *     Also clear the previous interrupt data on an open, and clean > - *     up things on a close. > + * We enforce only one user at a time here with the open/close. >  */ > - >  static int rtc_open(struct inode *inode, struct file *file) >  { > -       lock_kernel(); >        if( !atomic_dec_and_test(&rtc_ready) ) >        { >                atomic_inc( &rtc_ready ); > -               unlock_kernel(); >                return -EBUSY; >        } > -       unlock_kernel(); > - >        return 0; >  } > > @@ -151,9 +142,9 @@ static int rtc_release(struct inode *ino >  */ > >  static const struct file_operations rtc_fops = { > -       .ioctl =        rtc_ioctl, > -       .open =         rtc_open, > -       .release =      rtc_release, > +       .unlocked_ioctl = rtc_ioctl, > +       .open           = rtc_open, > +       .release        = rtc_release, >  }; > >  static struct miscdevice rtc_dev= Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds