Hi Greg,
On Thu, Sep 24, 2020 at 11:51:57AM +0200, Greg Kroah-Hartman wrote:
> On Thu, Sep 24, 2020 at 04:28:33PM +0800, Lee, Chun-Yi wrote:
> > This patch moved the logic of creating efivars mount point to the
> > registration of efivars abstraction. It's useful for userland to
> > determine the availability of efivars filesystem by checking the
> > existence of mount point.
>
> Why not do what all other tools do, and look in /proc/filesystems?
>
> Why is efivars "special" in this way? What tool isn't properly looking
> for the filesystem in that way today?
>
Thanks for your idea. I think that this is good enough for userland
tool to check the availability of efivarfs. Ignore my patch please.
Regards
Joey Lee
> > The 'efivars' platform device be created on generic EFI runtime services
> > platform, so it can be used to determine the availability of efivarfs.
> > But this approach is not available for google gsmi efivars abstraction.
>
> I do not understand this last sentence, can you try to explain it
> better?
>
> > This patch be tested on Here on qemu-OVMF and qemu-uboot.
>
> How about real hardware? :)
>
> >
> > Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
> > Cc: Matthias Brugger <mbrugger@xxxxxxxx>
> > Cc: Fabian Vogt <fvogt@xxxxxxxx>
> > Cc: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Cc: Arthur Heymans <arthur@xxxxxxxxxxxx>
> > Cc: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
> > Signed-off-by: "Lee, Chun-Yi" <jlee@xxxxxxxx>
> > ---
> > drivers/firmware/efi/efi.c | 7 -------
> > drivers/firmware/efi/vars.c | 17 +++++++++++++++++
> > 2 files changed, 17 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> > index 3aa07c3b5136..23c11a2a3f4d 100644
> > --- a/drivers/firmware/efi/efi.c
> > +++ b/drivers/firmware/efi/efi.c
> > @@ -405,13 +405,6 @@ static int __init efisubsys_init(void)
> > if (error)
> > goto err_remove_group;
> >
> > - /* and the standard mountpoint for efivarfs */
> > - error = sysfs_create_mount_point(efi_kobj, "efivars");
> > - if (error) {
> > - pr_err("efivars: Subsystem registration failed.\n");
> > - goto err_remove_group;
> > - }
> > -
> > if (efi_enabled(EFI_DBG) && efi_enabled(EFI_PRESERVE_BS_REGIONS))
> > efi_debugfs_init();
> >
> > diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
> > index 973eef234b36..6fa7f288d635 100644
> > --- a/drivers/firmware/efi/vars.c
> > +++ b/drivers/firmware/efi/vars.c
> > @@ -1179,6 +1179,8 @@ int efivars_register(struct efivars *efivars,
> > const struct efivar_operations *ops,
> > struct kobject *kobject)
> > {
> > + int error;
> > +
> > if (down_interruptible(&efivars_lock))
> > return -EINTR;
> >
> > @@ -1191,6 +1193,19 @@ int efivars_register(struct efivars *efivars,
> >
> > up(&efivars_lock);
> >
> > + /* and the standard mountpoint for efivarfs */
> > + if (efi_kobj) {
>
> Why test for this? Can it race?
>
> thanks,
>
> greg k-h
