[PATCH] Documentation: Fix confusing descriptions of rdinit and init

[PATCH] Documentation: Fix confusing descriptions of rdinit and init

[Nir Lichtman]

Problem: Documentation of init does not emphasize that it is only used
when initramfs failed to load and the legacy logic of direct root
partition mounting is started.
Documentation of rdinit uses the legacy term ramdisk even though
nowadays it controls the init process of initramfs.

Solution: Fix and modernize both.

Ref: init/main.c and the kernel doc article "Ramfs, rootfs and initramfs"

Signed-off-by: Nir Lichtman <nir@lichtman.org>
---
 Documentation/admin-guide/kernel-parameters.txt | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6c42061ca..63170346c 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2305,8 +2305,9 @@
 
 	init=		[KNL]
 			Format: <full_path>
-			Run specified binary instead of /sbin/init as init
-			process.
+			Run specified binary instead of /sbin/init as init process
+			from root partition, used in case init was not found
+			in the initramfs.
 
 	initcall_debug	[KNL] Trace initcalls as they are executed.  Useful
 			for working out where the kernel is dying during
@@ -6194,7 +6195,7 @@
 
 	rdinit=		[KNL]
 			Format: <full_path>
-			Run specified binary instead of /init from the ramdisk,
+			Run specified binary instead of /init from the initramfs,
 			used for early userspace startup. See initrd.
 
 	rdrand=		[X86,EARLY]
-- 
2.49.1