[openwrt/openwrt] kernel: copy kernel build dir on Per-Device Initramfs compilation

[LEDE Commits]

ansuel pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/d78dec3e19e3f2ab0f14ba6819357d50156b30b8

commit d78dec3e19e3f2ab0f14ba6819357d50156b30b8
Author: Christian Marangi <ansuelsmth at gmail.com>
AuthorDate: Mon Sep 16 18:38:16 2024 +0200

    kernel: copy kernel build dir on Per-Device Initramfs compilation
    
    To speedup compilation of Per-Device Initramfs, copy the kernel build
    directory for each rootfs ID.
    
    This permits concurrent execution of kernel build without conflicting
    with each other at the expense of additional disk space usage.
    
    To limit disk space usage, the copied kernel directory is deleted after
    the Per-Device Initramfs image is generated and saved.
    
    Link: https://github.com/openwrt/openwrt/pull/16404
    Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
---
 include/kernel-defaults.mk | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/kernel-defaults.mk b/include/kernel-defaults.mk
index fc1262aad3..e9e36d72b6 100644
--- a/include/kernel-defaults.mk
+++ b/include/kernel-defaults.mk
@@ -153,13 +153,13 @@ endif
 # $1: image suffix
 # $2: Per Device Rootfs ID
 define Kernel/CopyImage
-	cmp -s $(LINUX_DIR)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).debug$(2) || { \
-		$(KERNEL_CROSS)objcopy -O binary $(OBJCOPY_STRIP) -S $(LINUX_DIR)/vmlinux $(LINUX_KERNEL)$(1)$(2); \
-		$(KERNEL_CROSS)objcopy $(OBJCOPY_STRIP) -S $(LINUX_DIR)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).elf$(2); \
-		$(CP) $(LINUX_DIR)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).debug$(2); \
+	cmp -s $(LINUX_DIR)$(2)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).debug$(2) || { \
+		$(KERNEL_CROSS)objcopy -O binary $(OBJCOPY_STRIP) -S $(LINUX_DIR)$(2)/vmlinux $(LINUX_KERNEL)$(1)$(2); \
+		$(KERNEL_CROSS)objcopy $(OBJCOPY_STRIP) -S $(LINUX_DIR)$(2)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).elf$(2); \
+		$(CP) $(LINUX_DIR)$(2)/vmlinux $(KERNEL_BUILD_DIR)/vmlinux$(1).debug$(2); \
 		$(foreach k, \
 			$(if $(KERNEL_IMAGES),$(KERNEL_IMAGES),$(filter-out vmlinux dtbs,$(KERNELNAME))), \
-			$(CP) $(LINUX_DIR)/arch/$(LINUX_KARCH)/boot/$(IMAGES_DIR)/$(k) $(KERNEL_BUILD_DIR)/$(k)$(1)$(2); \
+			$(CP) $(LINUX_DIR)$(2)/arch/$(LINUX_KARCH)/boot/$(IMAGES_DIR)/$(k) $(KERNEL_BUILD_DIR)/$(k)$(1)$(2); \
 		) \
 	}
 endef
@@ -173,7 +173,9 @@ endef
 define Kernel/PrepareConfigPerRootfs
 	{ \
 		[ ! -d "$(1)" ] || rm -rf $(1); \
-		mkdir $(1) && $(CP) $(LINUX_DIR)/.config $(1); \
+		mkdir $(1) && $(CP) -T $(LINUX_DIR) $(1); \
+		touch $(1)/.config; \
+		rm -rf $(1)/usr/initramfs_data.cpio*; \
 	}
 endef
 
@@ -209,10 +211,9 @@ define Kernel/CompileImage/Initramfs
 			$(if $(CONFIG_TARGET_INITRAMFS_COMPRESSION_ZSTD), \
 				$(STAGING_DIR_HOST)/bin/zstd -T0 -f -o $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio.zstd $(if $(2),$(LINUX_DIR)$(2),$(KERNEL_BUILD_DIR))/initrd.cpio;) \
 			$(if $(2),,$(KERNEL_MAKE) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all);),\
-			$(call locked,$(if $(2),$(CP) $(LINUX_DIR)$(2)/.config* $(LINUX_DIR) && touch $(LINUX_DIR)/.config && ) \
-				rm -rf $(LINUX_DIR)/usr/initramfs_data.cpio* $(LINUX_DIR)/.config.prev && \
-				$(KERNEL_MAKE) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all), compile-initramfs);) \
+			$(KERNEL_MAKE) $(if $(2),-C $(LINUX_DIR)$(2)) $(KERNEL_MAKEOPTS_IMAGE) $(if $(KERNELNAME),$(KERNELNAME),all);) \
 		$(call Kernel/CopyImage,-initramfs,$(2)); \
+		$(if $(2),rm -rf $(LINUX_DIR)$(2);) \
 	}, gen-initramfs$(if $(2),-$(2)));
 endef
 else