docs: filesystems: convert efivarfs.txt to ReST

Trivial changes:

- Add a SPDX header;
- Adjust document title;
- Mark a literal block as such;
- Add it to filesystems/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/215691d747055c4ccb038ec7d78d8d1fe87fe2c0.1581955849.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

1 files changed, 0 insertions, 23 deletions

diff --git a/Documentation/filesystems/efivarfs.txt b/Documentation/filesystems/efivarfs.txt
deleted file mode 100644
index 686a64bba775..000000000000
--- a/Documentation/filesystems/efivarfs.txt
+++ /dev/null
@@ -1,23 +0,0 @@
-
-efivarfs - a (U)EFI variable filesystem
-
-The efivarfs filesystem was created to address the shortcomings of
-using entries in sysfs to maintain EFI variables. The old sysfs EFI
-variables code only supported variables of up to 1024 bytes. This
-limitation existed in version 0.99 of the EFI specification, but was
-removed before any full releases. Since variables can now be larger
-than a single page, sysfs isn't the best interface for this.
-
-Variables can be created, deleted and modified with the efivarfs
-filesystem.
-
-efivarfs is typically mounted like this,
-
-	mount -t efivarfs none /sys/firmware/efi/efivars
-
-Due to the presence of numerous firmware bugs where removing non-standard
-UEFI variables causes the system firmware to fail to POST, efivarfs
-files that are not well-known standardized variables are created
-as immutable files.  This doesn't prevent removal - "chattr -i" will work -
-but it does prevent this kind of failure from being accomplished
-accidentally.