Driver-Core: devtmpfs - remove EXPERIMENTAL and flush out the description

All major distros enable devtmpfs on recent systems, so remove
the EXPERIMENTAL flag, and make the description a bit more instructive.

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

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index ee37727..8021e19 100644 (file)
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -9,29 +9,36 @@ config UEVENT_HELPER_PATH
          every uevent.
 
 config DEVTMPFS
-       bool "Create a kernel maintained /dev tmpfs (EXPERIMENTAL)"
+       bool "Maintain a devtmpfs filesystem to mount at /dev"
        depends on HOTPLUG && SHMEM && TMPFS
        help
-         This creates a tmpfs filesystem, and mounts it at bootup
-         and mounts it at /dev. The kernel driver core creates device
-         nodes for all registered devices in that filesystem. All device
-         nodes are owned by root and have the default mode of 0600.
-         Userspace can add and delete the nodes as needed. This is
-         intended to simplify bootup, and make it possible to delay
-         the initial coldplug at bootup done by udev in userspace.
-         It should also provide a simpler way for rescue systems
-         to bring up a kernel with dynamic major/minor numbers.
-         Meaningful symlinks, permissions and device ownership must
-         still be handled by userspace.
-         If unsure, say N here.
+         This creates a tmpfs filesystem instance early at bootup.
+         In this filesystem, the kernel driver core maintains device
+         nodes with their default names and permissions for all
+         registered devices with an assigned major/minor number.
+         Userspace can modify the filesystem content as needed, add
+         symlinks, and apply needed permissions.
+         It provides a fully functional /dev directory, where usually
+         udev runs on top, managing permissions and adding meaningful
+         symlinks.
+         In very limited environments, it may provide a sufficient
+         functional /dev without any further help. It also allows simple
+         rescue systems, and reliably handles dynamic major/minor numbers.
 
 config DEVTMPFS_MOUNT
-       bool "Automount devtmpfs at /dev"
+       bool "Automount devtmpfs at /dev, after the kernel mounted the rootfs"
        depends on DEVTMPFS
        help
-         This will mount devtmpfs at /dev if the kernel mounts the root
-         filesystem. It will not affect initramfs based mounting.
-         If unsure, say N here.
+         This will instruct the kernel to automatically mount the
+         devtmpfs filesystem at /dev, directly after the kernel has
+         mounted the root filesystem. The behavior can be overridden
+         with the commandline parameter: devtmpfs.mount=0|1.
+         This option does not affect initramfs based booting, here
+         the devtmpfs filesystem always needs to be mounted manually
+         after the roots is mounted.
+         With this option enabled, it allows to bring up a system in
+         rescue mode with init=/bin/sh, even when the /dev directory
+         on the rootfs is completely empty.
 
 config STANDALONE
        bool "Select only drivers that don't need compile-time external firmware" if EXPERIMENTAL