sysfs: clarify SYSFS_DEPRECATED help text

This should make the help text of SYSFS_DEPRECATED more clear, that this
is _not_ about (what some people think it is) suppressing a few symlinks
and variables, but a different sysfs _layout_ with new features.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/init/Kconfig b/init/Kconfig
index 52847ee..d9d3dba 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -423,27 +423,37 @@ config SYSFS_DEPRECATED
        bool
 
 config SYSFS_DEPRECATED_V2
-       bool "Create deprecated sysfs files"
+       bool "Create deprecated sysfs layout for older userspace tools"
        depends on SYSFS
        default y
        select SYSFS_DEPRECATED
        help
-         This option creates deprecated symlinks such as the
-         "device"-link, the <subsystem>:<name>-link, and the
-         "bus"-link. It may also add deprecated key in the
-         uevent environment.
-         None of these features or values should be used today, as
-         they export driver core implementation details to userspace
-         or export properties which can't be kept stable across kernel
-         releases.
-
-         If enabled, this option will also move any device structures
-         that belong to a class, back into the /sys/class hierarchy, in
-         order to support older versions of udev and some userspace
-         programs.
-
-         If you are using a distro with the most recent userspace
-         packages, it should be safe to say N here.
+         This option switches the layout of sysfs to the deprecated
+         version.
+
+         The current sysfs layout features a unified device tree at
+         /sys/devices/, which is able to express a hierarchy between
+         class devices. If the deprecated option is set to Y, the
+         unified device tree is split into a bus device tree at
+         /sys/devices/ and several individual class device trees at
+         /sys/class/. The class and bus devices will be connected by
+         "<subsystem>:<name>" and the "device" links. The "block"
+         class devices, will not show up in /sys/class/block/. Some
+         subsystems will suppress the creation of some devices which
+         depend on the unified device tree.
+
+         This option is not a pure compatibility option that can
+         be safely enabled on newer distributions. It will change the
+         layout of sysfs to the non-extensible deprecated version,
+         and disable some features, which can not be exported without
+         confusing older userspace tools. Since 2007/2008 all major
+         distributions do not enable this option, and ship no tools which
+         depend on the deprecated layout or this option.
+
+         If you are using a new kernel on an older distribution, or use
+         older userspace tools, you might need to say Y here. Do not say Y,
+         if the original kernel, that came with your distribution, has
+         this option set to N.
 
 config PROC_PID_CPUSET
        bool "Include legacy /proc/<pid>/cpuset file"