do_mounts: Fix boot from ramdisk

Russell King investigated a failure case I introduced: When booting
with "load_ramdisk=1", we use the kernel root= parameter to determine
from what device to get the contents to copy into a ramdisk and then
mount that ramdisk as root.

For the copy to work, /dev/root needs to point to the device to load the
ramdisk from.

init/do_mounts.c

@@ -17,7 +17,7 @@ extern int get_filesystem_list(char * buf);
 int __initdata rd_doload;	/* 1 = load RAM disk, 0 = don't load */
 
 int root_mountflags = MS_RDONLY | MS_VERBOSE;
-static char * __initdata root_device_name;
+char * __initdata root_device_name;
 static char __initdata saved_root_name[64];
 
 /* this is initialized in init/main.c */

init/do_mounts.h

@@ -27,6 +27,7 @@ void  change_floppy(char *fmt, ...);
 void  mount_block_root(char *name, int flags);
 void  mount_root(void);
 extern int root_mountflags;
+extern char *root_device_name;
 
 #ifdef CONFIG_DEVFS_FS
 

init/do_mounts_rd.c

@@ -242,6 +242,7 @@ int __init rd_load_disk(int n)
 {
 	if (rd_prompt)
 		change_floppy("root floppy disk to be loaded into RAM disk");
+	create_dev("/dev/root", ROOT_DEV, root_device_name);
 	create_dev("/dev/ram", MKDEV(RAMDISK_MAJOR, n), NULL);
 	return rd_load_image("/dev/root");
 }