[power] Divorce suspend console code from swsusp.

- Create kernel/power/console.c
- Rename prepare_suspend_console() to pm_prepare_console() and 
  restore_console() to pm_restore_console().
- Add prototypes to include/linux/suspend.h.
- Make kernel/power/console.o dependent only on CONFIG_PM
- Simplify logic for SUSPEND_CONSOLE define
- Make software_resume() prepare console much earlier, so we can localize
  the loglevel variables in console.c. 
- Remove #ifdef CONFIG_VT from console.c, and just check for SUSPEND_CONSOLE.
  (Perhaps we should make entire file dependent on CONFIG_VT_CONSOLE?)
- Add kernel/power/power.h to share things across local files.

include/linux/suspend.h

@@ -85,6 +85,10 @@ static inline void software_suspend(void)
 extern void refrigerator(unsigned long);
 extern int freeze_processes(void);
 extern void thaw_processes(void);
+
+extern int pm_prepare_console(void);
+extern void pm_restore_console(void);
+
 #else
 static inline void refrigerator(unsigned long)
 {

kernel/power/Makefile

-obj-y				:= process.o
+obj-y				:= process.o console.o
 obj-$(CONFIG_SOFTWARE_SUSPEND)	+= swsusp.o

kernel/power/console.c

+#include <linux/vt_kern.h>
+#include <linux/kbd_kern.h>
+#include "power.h"
+
+static int new_loglevel = 7;
+static int orig_loglevel;
+static int orig_fgconsole, orig_kmsg;
+
+int pm_prepare_console(void)
+{
+	orig_loglevel = console_loglevel;
+	console_loglevel = new_loglevel;
+
+#ifdef SUSPEND_CONSOLE
+	orig_fgconsole = fg_console;
+
+	if(vc_allocate(SUSPEND_CONSOLE))
+	  /* we can't have a free VC for now. Too bad,
+	   * we don't want to mess the screen for now. */
+		return 1;
+
+	set_console (SUSPEND_CONSOLE);
+	if(vt_waitactive(SUSPEND_CONSOLE)) {
+		pr_debug("Suspend: Can't switch VCs.");
+		return 1;
+	}
+	orig_kmsg = kmsg_redirect;
+	kmsg_redirect = SUSPEND_CONSOLE;
+#endif
+	return 0;
+}
+
+void pm_restore_console(void)
+{
+	console_loglevel = orig_loglevel;
+#ifdef SUSPEND_CONSOLE
+	set_console (orig_fgconsole);
+#endif
+	return;
+}

kernel/power/power.h

+
+
+/* With SUSPEND_CONSOLE defined, it suspend looks *really* cool, but
+   we probably do not take enough locks for switching consoles, etc,
+   so bad things might happen.
+*/
+#if defined(CONFIG_VT) && defined(CONFIG_VT_CONSOLE)
+#define SUSPEND_CONSOLE	(MAX_NR_CONSOLES-1)
+#endif

kernel/power/swsusp.c

@@ -43,8 +43,8 @@
 #include <linux/version.h>
 #include <linux/delay.h>
 #include <linux/reboot.h>
-#include <linux/vt_kern.h>
 #include <linux/bitops.h>
+#include <linux/vt_kern.h>
 #include <linux/kbd_kern.h>
 #include <linux/keyboard.h>
 #include <linux/spinlock.h>
@@ -63,19 +63,12 @@
 #include <asm/pgtable.h>
 #include <asm/io.h>
 
+#include "power.h"
+
 extern long sys_sync(void);
 
 unsigned char software_suspend_enabled = 0;
 
-#define SUSPEND_CONSOLE	(MAX_NR_CONSOLES-1)
-/* With SUSPEND_CONSOLE defined, it suspend looks *really* cool, but
-   we probably do not take enough locks for switching consoles, etc,
-   so bad things might happen.
-*/
-#if !defined(CONFIG_VT) || !defined(CONFIG_VT_CONSOLE)
-#undef SUSPEND_CONSOLE
-#endif
-
 #define __ADDRESS(x)  ((unsigned long) phys_to_virt(x))
 #define ADDRESS(x) __ADDRESS((x) << PAGE_SHIFT)
 #define ADDRESS2(x) __ADDRESS(__pa(x))		/* Needed for x86-64 where some pages are in memory twice */
@@ -89,9 +82,6 @@ extern int is_head_of_free_region(struct page *);
 spinlock_t suspend_pagedir_lock __nosavedata = SPIN_LOCK_UNLOCKED;
 
 /* Variables to be preserved over suspend */
-static int new_loglevel = 7;
-static int orig_loglevel;
-static int orig_fgconsole, orig_kmsg;
 static int pagedir_order_check;
 static int nr_copy_pages_check;
 
@@ -455,40 +445,6 @@ static suspend_pagedir_t *create_suspend_pagedir(int nr_copy_pages)
 	return pagedir;
 }
 
-static int prepare_suspend_console(void)
-{
-	orig_loglevel = console_loglevel;
-	console_loglevel = new_loglevel;
-
-#ifdef CONFIG_VT
-	orig_fgconsole = fg_console;
-#ifdef SUSPEND_CONSOLE
-	if(vc_allocate(SUSPEND_CONSOLE))
-	  /* we can't have a free VC for now. Too bad,
-	   * we don't want to mess the screen for now. */
-		return 1;
-
-	set_console (SUSPEND_CONSOLE);
-	if(vt_waitactive(SUSPEND_CONSOLE)) {
-		PRINTK("Bummer. Can't switch VCs.");
-		return 1;
-	}
-	orig_kmsg = kmsg_redirect;
-	kmsg_redirect = SUSPEND_CONSOLE;
-#endif
-#endif
-	return 0;
-}
-
-static void restore_console(void)
-{
-	console_loglevel = orig_loglevel;
-#ifdef SUSPEND_CONSOLE
-	set_console (orig_fgconsole);
-#endif
-	return;
-}
-
 static int prepare_suspend_processes(void)
 {
 	sys_sync();	/* Syncing needs pdflushd, so do it before stopping processes */
@@ -743,7 +699,7 @@ void do_magic_suspend_2(void)
 static void do_software_suspend(void)
 {
 	arch_prepare_suspend();
-	if (prepare_suspend_console())
+	if (pm_prepare_console())
 		printk( "%sCan't allocate a console... proceeding\n", name_suspend);
 	if (!prepare_suspend_processes()) {
 
@@ -774,7 +730,7 @@ static void do_software_suspend(void)
 	}
 	software_suspend_enabled = 1;
 	MDELAY(1000);
-	restore_console();
+	pm_restore_console();
 }
 
 /*
@@ -997,8 +953,6 @@ static int __read_suspend_image(struct block_device *bdev, union diskpage *cur,
 		bdev_write_page(bdev, 0, cur);
 	}
 
-	if (prepare_suspend_console())
-		printk("%sCan't allocate a console... proceeding\n", name_resume);
 	printk( "%sSignature found, resuming\n", name_resume );
 	MDELAY(1000);
 
@@ -1119,8 +1073,8 @@ void software_resume(void)
 	}
 	MDELAY(1000);
 
-	orig_loglevel = console_loglevel;
-	console_loglevel = new_loglevel;
+	if (pm_prepare_console())
+		printk("swsusp: Can't allocate a console... proceeding\n");
 
 	if (!resume_file[0] && resume_status == RESUME_SPECIFIED) {
 		printk( "suspension device unspecified\n" );
@@ -1134,7 +1088,7 @@ void software_resume(void)
 	panic("This never returns");
 
 read_failure:
-	console_loglevel = orig_loglevel;
+	pm_restore_console();
 	return;
 }