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>

1 files changed, 27 insertions, 17 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 52847eec7398..d9d3dbabdb18 100644
--- 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"