[PATCH] swap= kernel commandline

[Kaj-Michael Lang]

This patch adds a swap kernel commandline option, so that you can add a
swap partition before init starts running on a low-memory machine. 

The patch is against 2.4.0-test11-pre7

This is my first try at a kernel patch so... I hope someone finds it
usefull.


--- init/main.c-2.4.0test11-pre7        Sat Nov 18 12:30:59 2000
+++ init/main.c Sat Nov 18 12:35:08 2000
@@ -131,6 +131,7 @@
 int root_mountflags = MS_RDONLY;
 char *execute_command;
 char root_device_name[64];
+char swap_device_name[64];
 
 
 static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
@@ -297,6 +298,25 @@
 
 __setup("root=", root_dev_setup);
 
+static int __init swap_dev_setup(char *line)
+{
+       int i;
+       char ch;
+
+       memset (swap_device_name, 0, sizeof swap_device_name);
+       for (i = 0; i < sizeof swap_device_name - 1; ++i)
+       {
+           ch = line[i];
+           if ( isspace (ch) || (ch == ',') || (ch == '\0') ) break;
+           swap_device_name[i] = ch;
+       }
+       return 1;
+}
+
+
+__setup("swap=", swap_dev_setup);
+
+
 static int __init checksetup(char *line)
 {
        struct kernel_param *p;
@@ -725,6 +745,15 @@
 
        mount_devfs_fs ();
 
+       if (swap_device_name[0]!=0) {
+         printk("Setting up swap: %s \n",swap_device_name);
+         if ( sys_swapon(swap_device_name,0)==0 ) {
+               printk("Swapon ok\n"); 
+               } else {
+               printk("Swapon failed!\n");
+               }
+       }
+ 
 #ifdef CONFIG_BLK_DEV_INITRD
        root_mountflags = real_root_mountflags;
        if (mount_initrd && ROOT_DEV != real_root_dev
@@ -780,3 +809,4 @@
        execve("/bin/sh",argv_init,envp_init);
        panic("No init found.  Try passing init= option to kernel.");
 }
+