Re: mem=16MB laptop testing

From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Andrew Morton <akpm@osdl.org>
Cc: wli@holomorphy.com, linux-kernel@vger.kernel.org
Subject: Re: mem=16MB laptop testing
Date: Tue, 14 Oct 2003 13:18:56 +0100	[thread overview]
Message-ID: <20031014131856.A17629@flint.arm.linux.org.uk> (raw)
In-Reply-To: <20031014051031.1d2b5f23.akpm@osdl.org>; from akpm@osdl.org on Tue, Oct 14, 2003 at 05:10:31AM -0700

On Tue, Oct 14, 2003 at 05:10:31AM -0700, Andrew Morton wrote:
> Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> > On Tue, Oct 14, 2003 at 04:56:14AM -0700, Andrew Morton wrote:
> > > I guess not mounting /sys doesn't help here.  It would be nice.  Maybe with
> > > a CONFIG_I_WILL_NEVER_MOUNT_SYSFS we could avoid all those allocations.
> > 
> > I believe sysfs is required for mounting the root filesystem - see
> > name_to_dev_t in init/do_mounts.c.
> 
> OK.  But it looks like if /sys is empty and you provide "root=03:02" then
> things will still work.  It's a matter of trying it...

Uhh?

dev_t name_to_dev_t(char *name)
{
        dev_t res = 0;

        sys_mkdir("/sys", 0700);
        if (sys_mount("sysfs", "/sys", "sysfs", 0, NULL) < 0)
                goto out;

	...

out:
        sys_rmdir("/sys");
        return res;
}

If sysfs can't be mounted, then it looks like we can't even decode a
numeric major:minor root device specification.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core