Re: [Patch] debugfs: remove module_exit()

[Cong Wang]

On 12/01/10 23:56, Greg KH wrote:
> On Wed, Dec 01, 2010 at 02:33:12PM +0800, Cong Wang wrote:
> > On 12/01/10 09:35, Greg KH wrote:
> > > On Tue, Nov 09, 2010 at 04:19:58AM -0500, Amerigo Wang wrote:
> > > > debugfs can't be a module, so module_exit() is meaningless
> > > > for it.
> > > >
> > > > Signed-off-by: WANG Cong<amwang@xxxxxxxxxx>
> > > >
> > > > ---
> > > > diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
> > > > index 37a8ca7..d38c88f 100644
> > > > --- a/fs/debugfs/inode.c
> > > > +++ b/fs/debugfs/inode.c
> > > > @@ -13,9 +13,6 @@
> > > >    *
> > > >    */
> > > >
> > > > -/* uncomment to get debug messages from the debug filesystem, ah the irony. */
> > > > -/* #define DEBUG */
> > >
> > > Why did you remove these lines?  They don't pertain to this patch.
> >
> > These lines are obsolete.
>
> Even if they were (and hint, I don't think they are), they have nothing
> to do with the patch you created so they don't belong here.  The rule is
> "one patch per logical change" and you didn't even describe that you
> were removing these lines in the changelog entry, so that's two strikes
> against removing these lines.

Ok, teach me where DEBUG is used in that file?


> > > > -
> > > >   #include<linux/module.h>
> > > >   #include<linux/fs.h>
> > > >   #include<linux/mount.h>
> > > > @@ -540,17 +537,5 @@ static int __init debugfs_init(void)
> > > >
> > > >   	return retval;
> > > >   }
> > > > -
> > > > -static void __exit debugfs_exit(void)
> > > > -{
> > > > -	debugfs_registered = false;
> > > > -
> > > > -	simple_release_fs(&debugfs_mount,&debugfs_mount_count);
> > > > -	unregister_filesystem(&debug_fs_type);
> > > > -	kobject_put(debug_kobj);
> > > > -}
> > >
> > > When the code is built into the kernel, the __exit function should go
> > > away, so this isn't costing us any extra memory, right?
> >
> >
> > Perhaps, but this can still reduce the vmlinux size, right?
>
> Which really doesn't matter, right?  How much is it reduced?
>
> > > And debugfs used to be able to be built as a module, perhaps it will be
> > > in the future?  I don't think this patch is really needed.
> >
> > Huh? Wasn't it a module before?
>
> Yes it was.
>
> > I think the problem is tracers use debugfs, it needs to depends on DEBUGFS=y.
>
> So if you disable tracing, then you could use debugfs as a module,
> right?  So the patch should not be applied.

No, that CONFIG is a bool, no way to make it as a module.
Since you insist, I will send a patch to make it as a module.

Thanks.
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