Re: [PATCH 5/5] fix rootfstype=tmpfs

[Stefan Berger <stefanb@linux.ibm.com>]

On 2/21/23 16:04, Rob Landley wrote:
> Wire up rootfstype=tmpfs to force rootfs to be tmpfs even when you specify root=
> 
> Initramfs automatically uses tmpfs (if available) when you DON'T specify a
> root= fallback root to mount over initramfs, but some people can't NOT do
> that for some reason (old bootloaders), so let rootfstype=tmpfs override it.
> 
> My original code tried to do this 10 years ago but got the test wrong,
> and nobody's corrected it since, so here you go...
> 
> Signed-off-by: Rob Landley <rob@landley.net>

I would like to be able to have this for some work with OpenBMC and 
ideally it would propagate to one of the recent kernels with a Fixes tag 
like this?

Fixes: 6e19eded3684 ("initmpfs: use initramfs if rootfstype= or root= 
specified")

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>

> 
> See https://lkml.iu.edu/hypermail/linux/kernel/2207.3/06939.html
> ---
>   init/do_mounts.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/init/do_mounts.c b/init/do_mounts.c
> index 811e94daf0a8..01d80fb828fd 100644
> --- a/init/do_mounts.c
> +++ b/init/do_mounts.c
> @@ -665,7 +665,7 @@ struct file_system_type rootfs_fs_type = {
>   
>   void __init init_rootfs(void)
>   {
> -	if (IS_ENABLED(CONFIG_TMPFS) && !saved_root_name[0] &&
> -		(!root_fs_names || strstr(root_fs_names, "tmpfs")))
> +	if (IS_ENABLED(CONFIG_TMPFS) && (!root_fs_names ? !saved_root_name[0] :
> +		!!strstr(root_fs_names, "tmpfs")))
>   		is_tmpfs = true;
>   }