[PATCH] skip initramfs check

[Marcelo Tosatti <marcelo.tosatti@cyclades.com>]

Hi, 

The initramfs check at populate_rootfs() can consume significant time
(several seconds) on slow/embedded platforms, since it has to decompress
the image.

Add an option to skip it under CONFIG_EMBEDDED.

Is there a nicer way to achieve the same result?

diff --git a/init/Kconfig b/init/Kconfig
index ea097e0..a9d709e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -398,6 +398,16 @@ config CC_ALIGN_JUMPS
 	  no dummy operations need be executed.
 	  Zero means use compiler's default.
 
+config INITRAMFS_SKIP
+	bool "Skip initramfs verification of initrd" if EMBEDDED
+	default n
+	help
+	  By default the initialization code uncompresses the initrd image to 
+	  verify if it is a initramfs image. 
+
+	  Say Y here if you are sure not to be using initramfs and want to
+	  skip that test.
+
 endmenu		# General setup
 
 config TINY_SHMEM
diff --git a/init/initramfs.c b/init/initramfs.c
index 0c5d9a3..92628b0 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -486,6 +486,7 @@ void __init populate_rootfs(void)
 	if (initrd_start) {
 		int fd;
 		printk(KERN_INFO "checking if image is initramfs...");
+#ifndef CONFIG_INITRAMFS_SKIP
 		err = unpack_to_rootfs((char *)initrd_start,
 			initrd_end - initrd_start, 1);
 		if (!err) {
@@ -495,6 +496,7 @@ void __init populate_rootfs(void)
 			free_initrd();
 			return;
 		}
+#endif
 		printk("it isn't (%s); looks like an initrd\n", err);
 		fd = sys_open("/initrd.image", O_WRONLY|O_CREAT, 700);
 		if (fd >= 0) {