Re: [RFC][PATCH 5/14] Introduce union stack

[Paul Dickson <paul@permanentmail.com>]

On Mon, 14 May 2007 13:23:06 -0700, Badari Pulavarty wrote:

> > +	while (fs) {
> > +		locked = union_trylock(fs->root);
> > +		if (!locked)
> > +			goto loop1;
> > +		locked = union_trylock(fs->altroot);
> > +		if (!locked)
> > +			goto loop2;
> > +		locked = union_trylock(fs->pwd);
> > +		if (!locked)
> > +			goto loop3;
> > +		break;
> > +	loop3:
> > +		union_unlock(fs->altroot);
> > +	loop2:
> > +		union_unlock(fs->root);
> > +	loop1:
> > +		read_unlock(&fs->lock);
> > +		UM_DEBUG_LOCK("Failed to get all semaphores in fs_struct!\n");
> > +		cpu_relax();
> > +		read_lock(&fs->lock);
> > +		continue;
> 
> Nit.. why "continue" ?
> 
> > +	}
> > +	BUG_ON(!fs);

How about getting rid of the gotos:

	while (fs) {
		locked = union_trylock(fs->root);
		if (locked) {
			locked = union_trylock(fs->altroot);
			if (locked) {
				locked = union_trylock(fs->pwd);
				if (locked)
					break;
				else {
					union_unlock(fs->altroot);
					union_unlock(fs->root);
				}
			else
				union_unlock(fs->root);
			}
		}
		read_unlock(&fs->lock);
		UM_DEBUG_LOCK("Failed to get all semaphores in fs_struct!\n");
		cpu_relax();
		read_lock(&fs->lock);
	}
	BUG_ON(!fs);

It's the same number of lines.  Shorter if you get rid of the "locked"
variable.

	-Paul