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

[John Kacur]

On Mon, 12 Oct 2009, Takashi Iwai wrote:

> 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.
> 

Thank you for your review Takashi.

I corrected the style problems, and added a bit of spacing to make the 
code more readable.

Version 5 follows