Re: [PATCH] sound_core.c: Remove BKL from soundcore_open

[Takashi Iwai]

At Mon, 12 Oct 2009 10:37:05 +0200 (CEST),
John Kacur wrote:
> 
> On Mon, 12 Oct 2009, Takashi Iwai wrote:
> 
> > At Sun, 11 Oct 2009 14:41:15 +0200 (CEST),
> > John Kacur wrote:
> > > 
> > > @@ -631,17 +629,17 @@ static int soundcore_open(struct inode *inode, struct file *file)
> > >  		file->f_op = new_fops;
> > >  		spin_unlock(&sound_loader_lock);
> > >  		if(file->f_op->open)
> > > +			lock_kernel();
> > >  			err = file->f_op->open(inode,file);
> > > +			unlock_kernel();
> > 
> > You certainly want braces around here, no?
> > 
> 
> Oh, I don't know, I was kinda hoping that the spaces would magically 
> impart bracketnishish to the whole thing. My God yes we want the brackets -
> Thank you Takashi!
> 
> What follows is version four.
> 
> >From 90f527d2ae660a3a0e712075479a4cc24504ad45 Mon Sep 17 00:00:00 2001
> From: John Kacur <jkacur@xxxxxxxxxx>
> Date: Sun, 11 Oct 2009 14:25:46 +0200
> Subject: [PATCH] soundcore_open: Reduce the area BKL coverage in this function.
> 
> Most of this function is protected by the sound_loader_lock.
> We can push down the BKL to this call out err = file->f_op->open(inode,file);
> 
> Signed-off-by: John Kacur <jkacur@xxxxxxxxxx>
> Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
> ---
>  sound/sound_core.c |   10 ++++------
>  1 files changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/sound/sound_core.c b/sound/sound_core.c
> index 49c9981..643a61f 100644
> --- a/sound/sound_core.c
> +++ b/sound/sound_core.c
> @@ -576,8 +576,6 @@ static int soundcore_open(struct inode *inode, struct file *file)
>  	struct sound_unit *s;
>  	const struct file_operations *new_fops = NULL;
>  
> -	lock_kernel ();
> -
>  	chain=unit&0x0F;
>  	if(chain==4 || chain==5)	/* dsp/audio/dsp16 */
>  	{
> @@ -630,18 +628,18 @@ static int soundcore_open(struct inode *inode, struct file *file)
>  		const struct file_operations *old_fops = file->f_op;
>  		file->f_op = new_fops;
>  		spin_unlock(&sound_loader_lock);
> -		if(file->f_op->open)
> +		if(file->f_op->open) {
> +			lock_kernel();
>  			err = file->f_op->open(inode,file);
> -		if (err) {
> +			unlock_kernel();
> +		} if (err) {

It's better to break the line after the closing brace here.


Takashi
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