[PATCH] swsusp: thaw userspace and kernel space separately

Modify process thawing so that we can thaw kernel space without thawing
userspace, and thaw kernelspace first.  This will be useful in later
patches, where I intend to get swsusp thawing kernel threads only before
seeking to free memory.

Signed-off-by: Nigel Cunningham <nigel@suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/power/process.c

@@ -153,18 +153,29 @@ int freeze_processes(void)
 	return 0;
 }
 
-void thaw_processes(void)
+void thaw_some_processes(int all)
 {
 	struct task_struct *g, *p;
+	int pass = 0; /* Pass 0 = Kernel space, 1 = Userspace */
 
 	printk("Restarting tasks... ");
 	read_lock(&tasklist_lock);
-	do_each_thread(g, p) {
-		if (!freezeable(p))
-			continue;
-		if (!thaw_process(p))
-			printk(KERN_INFO "Strange, %s not stopped\n", p->comm);
-	} while_each_thread(g, p);
+	do {
+		do_each_thread(g, p) {
+			/*
+			 * is_user = 0 if kernel thread or borrowed mm,
+			 * 1 otherwise.
+			 */
+			int is_user = !!(p->mm && !(p->flags & PF_BORROWED_MM));
+			if (!freezeable(p) || (is_user != pass))
+				continue;
+			if (!thaw_process(p))
+				printk(KERN_INFO
+					"Strange, %s not stopped\n", p->comm);
+		} while_each_thread(g, p);
+
+		pass++;
+	} while (pass < 2 && all);
 
 	read_unlock(&tasklist_lock);
 	schedule();