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?
> 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
