From 821d1af0804825f01bdd540b626d81ea95a5414a Mon Sep 17 00:00:00 2001
From: Xunlei Pang <xlpang@redhat.com>
Date: Fri, 7 Jul 2017 15:48:57 +0800
Subject: [PATCH] mkdumprd: omit dracut modules in case of no dm target

In case of on dm related target, we can clearly and safely
remove many unnecessary modules to reduce initramfs size,
and to enhance stability.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
---
 mkdumprd | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/mkdumprd b/mkdumprd
index 644b5ce..9c5339c 100644
--- a/mkdumprd
+++ b/mkdumprd
@@ -372,16 +372,44 @@ check_crypt()
     return 1
 }
 
+is_dm()
+{
+    if [ -d "/sys/dev/block/$1/dm" ]; then
+        return 0
+    fi
+
+    return 1
+}
+
 crypt_exists=0
 omit_dracut_modules()
 {
+    local target majmin
+    local dm_exists
+
     # Skip fadump case
     is_fadump_capable && return
 
+    dm_exists=0
+
+    for target in $(get_kdump_targets); do
+        if [ -b "$target" ]; then
+            majmin=$(get_maj_min $target)
+            # Check "dm"
+            check_block_and_slaves is_dm $majmin && dm_exists=1
+        fi
+    done
+
     # Omit "crypt", BZ1451717
     if [ "$crypt_exists" == "0" ]; then
         add_dracut_arg "--omit" "crypt"
     fi
+
+    # Further omit more modules in case of no dm related target
+    if [ "$dm_exists" == "0" ]; then
+        # "dm_exists=0" implies "crypt_exists=0"
+        add_dracut_arg "--omit" "lvm dm multipath dmraid"
+    fi
 }
 
 if ! check_resettable; then