Re: [patch] pipe: Don't oops when pipe filesystem isn't mounted

[Andrew Morton <akpm@osdl.org>]

On Mon, 11 Dec 2006 08:01:40 -0800 (PST)
Linus Torvalds <torvalds@osdl.org> wrote:

> 
> 
> On Mon, 11 Dec 2006, Al Viro wrote:
> 
> > On Mon, Dec 11, 2006 at 02:27:46AM -0800, Andrew Morton wrote:
> > > @@ -115,6 +115,11 @@ extern void setup_arch(char **);
> > >  #define device_initcall_sync(fn)	__define_initcall("6s",fn,6s)
> > >  #define late_initcall(fn)		__define_initcall("7",fn,7)
> > >  #define late_initcall_sync(fn)		__define_initcall("7s",fn,7s)
> > > +#define populate_rootfs_initcall(fn)	__define_initcall("8",fn,8)
> > > +#define populate_rootfs_initcall_sync(fn) __define_initcall("8s",fn,8s)
> > > +#define rootfs_neeeded_initcall(fn)	__define_initcall("9",fn,9)
> > > +#define rootfs_neeeded_initcall_sync(fn) __define_initcall("9s",fn,9s)
> > 
> > Ewww....  After module_init()?  Please, don't.  Come on, if it can
> > be a module, it _must_ be ready to run late in the game.
> 
> Yeah, I think you should just run "populate_rootfs()" just before 
> "module_init" (which is the same as "device_initcall()").
> 
> So perhaps somethign like this? (totally untested)
> 
> Btw, if the linker sorts sections some way (does it?) we could probably 
> just make the vmlinux.lds.S file do
> 
> 	*(.initcall*.init)
> 
> or something, and then just let special cases like this use
> 
> 	__initcall(myfn, 5.1);
> 
> to show that it's between levels 5 and 6. But that would depend on the 
> linker section beign sorted alphabetically. Does anybody know if the 
> linker sorts these things somehow?
> 
> This patch is totally untested, but it looks obvious. It just says that 
> we'll populate rootfs _after_ we've done the fs-level initcalls, but 
> before we do any actual "device" initcalls.
> 
> If any really core stuff needs user-land - tough titties, as they say.
> 
> 		Linus
> ----
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index 6e9fceb..7437cca 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -242,6 +242,7 @@
>    	*(.initcall4s.init)						\
>    	*(.initcall5.init)						\
>    	*(.initcall5s.init)						\
> +	*(.initcallrootfs.init)						\
>    	*(.initcall6.init)						\
>    	*(.initcall6s.init)						\
>    	*(.initcall7.init)						\
> diff --git a/include/linux/init.h b/include/linux/init.h
> index 5eb5d24..5a593a1 100644
> --- a/include/linux/init.h
> +++ b/include/linux/init.h
> @@ -111,6 +111,7 @@ extern void setup_arch(char **);
>  #define subsys_initcall_sync(fn)	__define_initcall("4s",fn,4s)
>  #define fs_initcall(fn)			__define_initcall("5",fn,5)
>  #define fs_initcall_sync(fn)		__define_initcall("5s",fn,5s)
> +#define rootfs_initcall(fn)		__define_initcall("rootfs",fn,rootfs)
>  #define device_initcall(fn)		__define_initcall("6",fn,6)
>  #define device_initcall_sync(fn)	__define_initcall("6s",fn,6s)
>  #define late_initcall(fn)		__define_initcall("7",fn,7)

Looks like this might break pcmcia which for some reason does firmware
requesting at fs_initcall level (drivers/pcmcia/ds.c).