6 files changed, 48 insertions, 1 deletions

diff --git a/block/elevator.c b/block/elevator.c
index 9edba1b8323e..c2d61d56e0b7 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -136,6 +136,22 @@ static int __init elevator_setup(char *str)
 
 __setup("elevator=", elevator_setup);
 
+/* called during boot to load the elevator chosen by the elevator param */
+void __init load_default_elevator_module(void)
+{
+        struct elevator_type *e;
+
+        if (!chosen_elevator[0])
+                return;
+
+        spin_lock(&elv_list_lock);
+        e = elevator_find(chosen_elevator);
+        spin_unlock(&elv_list_lock);
+
+        if (!e)
+                request_module("%s-iosched", chosen_elevator);
+}
+
 static struct kobj_type elv_ktype;
 
 static struct elevator_queue *elevator_alloc(struct request_queue *q,
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index c03af7687bb4..186620631750 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -138,6 +138,7 @@ extern void elv_drain_elevator(struct request_queue *);
 /*
  * io scheduler registration
  */
+extern void __init load_default_elevator_module(void);
 extern int elv_register(struct elevator_type *);
 extern void elv_unregister(struct elevator_type *);
 
@@ -206,5 +207,9 @@ enum {
         INIT_LIST_HEAD(&(rq)->csd.list);        \
         } while (0)
 
+#else /* CONFIG_BLOCK */
+
+static inline void load_default_elevator_module(void) { }
+
 #endif /* CONFIG_BLOCK */
 #endif
diff --git a/include/linux/init.h b/include/linux/init.h
index a799273714ac..9230c9408d8b 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -161,6 +161,7 @@ extern unsigned int reset_devices;
 /* used by init/main.c */
 void setup_arch(char **);
 void prepare_namespace(void);
+void __init load_default_modules(void);
 
 extern void (*late_time_init)(void);
 
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 5e4ded51788e..dfe606a7dd61 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -57,6 +57,9 @@ static void __init handle_initrd(void)
         sys_mkdir("/old", 0700);
         sys_chdir("/old");
 
+        /* try loading default modules from initrd */
+        load_default_modules();
+
         /*
          * In case that a resume from disk is carried out by linuxrc or one of
          * its children, we need to tell the freezer not to wait for us.
diff --git a/init/initramfs.c b/init/initramfs.c
index 84c6bf111300..a67ef9dbda9d 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -592,7 +592,7 @@ static int __init populate_rootfs(void)
                         initrd_end - initrd_start);
                 if (!err) {
                         free_initrd();
-                        return 0;
+                        goto done;
                 } else {
                         clean_rootfs();
                         unpack_to_rootfs(__initramfs_start, __initramfs_size);
@@ -607,6 +607,7 @@ static int __init populate_rootfs(void)
                         sys_close(fd);
                         free_initrd();
                 }
+        done:
 #else
                 printk(KERN_INFO "Unpacking initramfs...\n");
                 err = unpack_to_rootfs((char *)initrd_start,
@@ -615,6 +616,11 @@ static int __init populate_rootfs(void)
                         printk(KERN_EMERG "Initramfs unpacking failed: %s\n", err);
                 free_initrd();
 #endif
+                /*
+                 * Try loading default modules from initramfs.  This gives
+                 * us a chance to load before device_initcalls.
+                 */
+                load_default_modules();
         }
         return 0;
 }
diff --git a/init/main.c b/init/main.c
index baf1f0f5c461..18efadb11cf6 100644
--- a/init/main.c
+++ b/init/main.c
@@ -70,6 +70,8 @@
 #include <linux/perf_event.h>
 #include <linux/file.h>
 #include <linux/ptrace.h>
+#include <linux/blkdev.h>
+#include <linux/elevator.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -794,6 +796,17 @@ static void __init do_pre_smp_initcalls(void)
                 do_one_initcall(*fn);
 }
 
+/*
+ * This function requests modules which should be loaded by default and is
+ * called twice right after initrd is mounted and right before init is
+ * exec'd.  If such modules are on either initrd or rootfs, they will be
+ * loaded before control is passed to userland.
+ */
+void __init load_default_modules(void)
+{
+        load_default_elevator_module();
+}
+
 static int run_init_process(const char *init_filename)
 {
         argv_init[0] = init_filename;
@@ -898,4 +911,7 @@ static void __init kernel_init_freeable(void)
          * we're essentially up and running. Get rid of the
          * initmem segments and start the user-mode stuff..
          */
+
+        /* rootfs is available now, try loading default modules */
+        load_default_modules();
 }