[PATCH] swsusp: try_to_freeze to make freezing hooks nicer

This moves refrigerator changes to sched.h, so that every file user of
refrigerator does not have to include suspend.h, and makes refrigerator
support easier by introducing try_to_freeze.

Adapted from patch by Nigel Cunningham
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/sched.h

@@ -1124,6 +1124,34 @@ extern void normalize_rt_tasks(void);
 
 #endif
 
+/* try_to_freeze
+ *
+ * Checks whether we need to enter the refrigerator
+ * and returns 1 if we did so.
+ */
+#ifdef CONFIG_PM
+extern void refrigerator(unsigned long);
+extern int freeze_processes(void);
+extern void thaw_processes(void);
+
+static inline int try_to_freeze(unsigned long refrigerator_flags)
+{
+	if (unlikely(current->flags & PF_FREEZE)) {
+		refrigerator(refrigerator_flags);
+		return 1;
+	} else
+		return 0;
+}
+#else
+static inline void refrigerator(unsigned long flag) {}
+static inline int freeze_processes(void) { BUG(); }
+static inline void thaw_processes(void) {}
+
+static inline int try_to_freeze(unsigned long refrigerator_flags)
+{
+	return 0;
+}
+#endif /* CONFIG_PM */
 #endif /* __KERNEL__ */
 
 #endif

include/linux/suspend.h

@@ -36,26 +36,16 @@ extern void mark_free_pages(struct zone *zone);
 /* kernel/power/swsusp.c */
 extern int software_suspend(void);
 
-#else	/* CONFIG_SOFTWARE_SUSPEND */
+extern int pm_prepare_console(void);
+extern void pm_restore_console(void);
+
+#else
 static inline int software_suspend(void)
 {
 	printk("Warning: fake suspend called\n");
 	return -EPERM;
 }
-#endif	/* CONFIG_SOFTWARE_SUSPEND */
-
-
-#ifdef CONFIG_PM
-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 flag) {}
-#endif	/* CONFIG_PM */
+#endif
 
 #ifdef CONFIG_SMP
 extern void disable_nonboot_cpus(void);