[PATCH 5/5] crash: clean up CRASH_DUMP

[Baoquan He]

By splitting CRASH_CORE into CRASH_RESERVE and VMCORE_INFO, and cleaning
up the dependency of FA_DMUMP on CRASH_DUMP, now we can rearrange CRASH_DUMP
to depend on KEXEC_CORE, and select CRASH_RESERVE and VMCORE_INFO.

KEXEC_CORE won't select CRASH_RESERVE and VMCORE_INFO any more because
KEXEC_CORE enables codes which allocate control pages, copy
kexec/kdump segments, and prepare for switching. These codes are shared
by both kexec_load and kexec_file_load, and by both kexec reboot and
kdump.

Doing this to make codes and the corresponding config items more
logical.

PROC_KCORE -----------> VMCORE_INFO

           |----------> VMCORE_INFO
FA_DUMP----|
           |----------> CRASH_RESERVE

                                                ---->VMCORE_INFO
                                               /
                                               |---->CRASH_RESERVE
KEXEC      --|                                /|
             |--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE
KEXEC_FILE --|                               \ |
                                               \---->CRASH_HOTPLUG

KEXEC      --|
             |--> KEXEC_CORE--> kexec reboot
KEXEC_FILE --|

Previously, LKP reported a building error. When investigating, it can't
be resolved reasonablly with the present messy kdump config items. With
the prepartory patches and chaneg at above, the LKP reported issue can
be solved now.

Signed-off-by: Baoquan He <bhe at redhat.com>
Reported-by: kernel test robot <lkp at intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312182200.Ka7MzifQ-lkp@intel.com/
---
 kernel/Kconfig.kexec | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
index 8faf27043432..6c34e63c88ff 100644
--- a/kernel/Kconfig.kexec
+++ b/kernel/Kconfig.kexec
@@ -9,8 +9,6 @@ config VMCORE_INFO
 	bool
 
 config KEXEC_CORE
-	select VMCORE_INFO
-	select CRASH_RESERVE
 	bool
 
 config KEXEC_ELF
@@ -99,8 +97,11 @@ config KEXEC_JUMP
 
 config CRASH_DUMP
 	bool "kernel crash dumps"
+	default y
 	depends on ARCH_SUPPORTS_CRASH_DUMP
-	select KEXEC_CORE
+	depends on KEXEC_CORE
+	select VMCORE_INFO
+	select CRASH_RESERVE
 	help
 	  Generate crash dump after being started by kexec.
 	  This should be normally only set in special crash dump kernels
-- 
2.41.0