Re: [tip:bkl/drivers] nvram: Drop the BKL from nvram_open()

[John Kacur]

On Wed, 14 Oct 2009, tip-bot for Ingo Molnar wrote:

> Commit-ID:  83cb16727085b18191f45eb0ede6bf1f97d67a7a
> Gitweb:     http://git.kernel.org/tip/83cb16727085b18191f45eb0ede6bf1f97d67a7a
> Author:     Ingo Molnar <mingo@xxxxxxx>
> AuthorDate: Wed, 14 Oct 2009 17:48:38 +0200
> Committer:  Ingo Molnar <mingo@xxxxxxx>
> CommitDate: Wed, 14 Oct 2009 17:54:03 +0200
> 
> nvram: Drop the BKL from nvram_open()
> 
> It's safe to remove the BKL from nvram_open(): there's no open()
> versus read() races: nvram_init() is very simple and race-free,
> it registers the device then puts it into /proc - there's no
> state init to race with.
> 
> Cc: Wim Van Sebroeck <wim@xxxxxxxxx>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> LKML-Reference: <1255116426-7270-1-git-send-email-fweisbec@xxxxxxxxx>
> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> ---
>  drivers/char/nvram.c |    3 ---
>  1 files changed, 0 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
> index 2100a8f..7cf4518 100644
> --- a/drivers/char/nvram.c
> +++ b/drivers/char/nvram.c
> @@ -329,14 +329,12 @@ static int nvram_ioctl(struct inode *inode, struct file *file,
>  
>  static int nvram_open(struct inode *inode, struct file *file)
>  {
> -	lock_kernel();
>  	spin_lock(&nvram_state_lock);
>  
>  	if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
>  	    (nvram_open_mode & NVRAM_EXCL) ||
>  	    ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
>  		spin_unlock(&nvram_state_lock);
> -		unlock_kernel();
>  		return -EBUSY;
>  	}
>  
> @@ -347,7 +345,6 @@ static int nvram_open(struct inode *inode, struct file *file)
>  	nvram_open_cnt++;
>  
>  	spin_unlock(&nvram_state_lock);
> -	unlock_kernel();
>  
>  	return 0;
>  }
> --
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This patch and a previous one remove the bkl from the open and llseek 
functions. We can also convert to an unlocked_ioctl