docs: ioctl-number: document fscrypt ioctl numbers
The 'f' ioctls with numbers 19-26 decimal are currently used for fscrypt
(a.k.a. ext4/f2fs/ubifs encryption), and up to 39 decimal is reserved
for future fscrypt use, as per the comment in fs/ext4/ext4.h. So the
reserved range is 13-27 hex.
Document this in ioctl-number.rst.
Signed-off-by: Eric Biggers <ebiggers@google.com>
diff --git a/Documentation/ioctl/ioctl-number.rst b/Documentation/ioctl/ioctl-number.rst
index bef79cd..4ef8643 100644
--- a/Documentation/ioctl/ioctl-number.rst
+++ b/Documentation/ioctl/ioctl-number.rst
@@ -233,6 +233,7 @@
'f' 00-0F fs/ext4/ext4.h conflict!
'f' 00-0F linux/fs.h conflict!
'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict!
+'f' 13-27 linux/fscrypt.h
'f' 81-8F linux/fsverity.h
'g' 00-0F linux/usb/gadgetfs.h
'g' 20-2F linux/usb/g_printer.h