kernfs: remove static node creation, and update the text

This is to match the "new" way of device handling with devtmpfs (already
widely used in recent ten years).

In a normal booting process, the kernel mounts devtmpfs at very early
stage.  So the static nodes won't be used at all.  The only situation
where the kernel can't mount devtmpfs is "/dev is missing", but it means
those two static nodes can't exist anyway, and a normal LFS system
(without initramfs) won't boot in such a bad situation.

Removing static /dev/console and /dev/null may cause trouble for those
people or scripts chroot into LFS tree without mounting devtmpfs.  But
entering a chroot with only console and null in /dev is already
problematic.  For a reference, If a systemd service is started with
PrivateDevices=true, systemd will create 18 nodes and symlinks to form a
"minimal" /dev.

1 files changed, 13 insertions, 32 deletions

diff --git a/chapter07/kernfs.xml b/chapter07/kernfs.xml
index f34155d7b..8746ea1e9 100644
--- a/chapter07/kernfs.xml
+++ b/chapter07/kernfs.xml
@@ -24,41 +24,22 @@
 
 <screen><userinput>mkdir -pv $LFS/{dev,proc,sys,run}</userinput></screen>
 
-  <sect2>
-    <title>Creating Initial Device Nodes</title>
-
-    <para>When the kernel boots the system, it requires the presence of a few
-    device nodes, in particular the <filename
-    class="devicefile">console</filename> and <filename
-    class="devicefile">null</filename> devices. The device nodes must be
-    created on the hard disk so that they are available before the kernel
-    populates <systemitem class="filesystem">/dev</systemitem>), and
-    additionally when Linux is started with
-    <parameter>init=/bin/bash</parameter>. Create the devices by running the
-    following commands:</para>
-
-<screen><userinput>mknod -m 600 $LFS/dev/console c 5 1
-mknod -m 666 $LFS/dev/null c 1 3</userinput></screen>
-
-  </sect2>
-
   <sect2 id="ch-tools-bindmount">
     <title>Mounting and Populating /dev</title>
 
-      <para>The recommended method of populating the <filename
-      class="directory">/dev</filename> directory with devices is to mount a
-      virtual filesystem (such as <systemitem
-      class="filesystem">tmpfs</systemitem>) on the <filename
-      class="directory">/dev</filename> directory, and allow the devices to be
-      created dynamically on that virtual filesystem as they are detected or
-      accessed. Device creation is generally done during the boot process
-      by Udev. Since this new system does not yet have Udev and has not yet
-      been booted, it is necessary to mount and populate <filename
-      class="directory">/dev</filename> manually. This is accomplished by bind
-      mounting the host system's <filename class="directory">/dev</filename>
-      directory. A bind mount is a special type of mount that allows you to
-      create a mirror of a directory or mount point to some other location. Use
-      the following command to achieve this:</para>
+      <para>During a normal boot, the kernel automatically mounts the
+      <systemitem class="filesystem">devtmpfs</systemitem> filesystem on the
+      <filename class="directory">/dev</filename> directory, and allow the
+      devices to be created dynamically on that virtual filesystem as they
+      are detected or accessed. Device creation is generally done during the
+      boot process by Udev. Since this new system does not yet have Udev and
+      has not yet been booted, it is necessary to mount and populate
+      <filename class="directory">/dev</filename> manually. This is
+      accomplished by bind mounting the host system's
+      <filename class="directory">/dev</filename> directory. A bind mount is
+      a special type of mount that allows you to create a mirror of a
+      directory or mount point to some other location. Use the following
+      command to achieve this:</para>
 
 <screen><userinput>mount -v --bind /dev $LFS/dev</userinput></screen>