X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fpower%2Fprocess.c;h=6d566bf7085c0b4fd7803a14cbaabef07269198e;hb=eee3c859c486d4f110f154807430eaf825ff4a3d;hp=fedabad5a180243e36fd93741668c9c8aa44e265;hpb=14b5b7cfaa110b1d25b8f80b01a8c97cf2db30bc;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/power/process.c b/kernel/power/process.c
index fedabad..6d566bf 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -20,14 +20,15 @@
  */
 #define TIMEOUT	(20 * HZ)
 
+#define FREEZER_KERNEL_THREADS 0
+#define FREEZER_USER_SPACE 1
 
 static inline int freezeable(struct task_struct * p)
 {
 	if ((p == current) || 
 	    (p->flags & PF_NOFREEZE) ||
 	    (p->exit_state == EXIT_ZOMBIE) ||
-	    (p->exit_state == EXIT_DEAD) ||
-	    (p->state == TASK_STOPPED))
+	    (p->exit_state == EXIT_DEAD))
 		return 0;
 	return 1;
 }
@@ -59,10 +60,16 @@ static inline void freeze_process(struct task_struct *p)
 	unsigned long flags;
 
 	if (!freezing(p)) {
-		freeze(p);
-		spin_lock_irqsave(&p->sighand->siglock, flags);
-		signal_wake_up(p, 0);
-		spin_unlock_irqrestore(&p->sighand->siglock, flags);
+		rmb();
+		if (!frozen(p)) {
+			if (p->state == TASK_STOPPED)
+				force_sig_specific(SIGSTOP, p);
+
+			freeze(p);
+			spin_lock_irqsave(&p->sighand->siglock, flags);
+			signal_wake_up(p, p->state == TASK_STOPPED);
+			spin_unlock_irqrestore(&p->sighand->siglock, flags);
+		}
 	}
 }
 
@@ -79,94 +86,132 @@ static void cancel_freezing(struct task_struct *p)
 	}
 }
 
-/* 0 = success, else # of processes that we failed to stop */
-int freeze_processes(void)
+static inline int is_user_space(struct task_struct *p)
+{
+	return p->mm && !(p->flags & PF_BORROWED_MM);
+}
+
+static unsigned int try_to_freeze_tasks(int freeze_user_space)
 {
-	int todo, nr_user, user_frozen;
-	unsigned long start_time;
 	struct task_struct *g, *p;
+	unsigned long end_time;
+	unsigned int todo;
 
-	printk("Stopping tasks... ");
-	start_time = jiffies;
-	user_frozen = 0;
+	end_time = jiffies + TIMEOUT;
 	do {
-		nr_user = todo = 0;
+		todo = 0;
 		read_lock(&tasklist_lock);
 		do_each_thread(g, p) {
 			if (!freezeable(p))
 				continue;
+
 			if (frozen(p))
 				continue;
+
 			if (p->state == TASK_TRACED && frozen(p->parent)) {
 				cancel_freezing(p);
 				continue;
 			}
-			if (p->mm && !(p->flags & PF_BORROWED_MM)) {
-				/* The task is a user-space one.
-				 * Freeze it unless there's a vfork completion
-				 * pending
+			if (is_user_space(p)) {
+				if (!freeze_user_space)
+					continue;
+
+				/* Freeze the task unless there is a vfork
+				 * completion pending
 				 */
 				if (!p->vfork_done)
 					freeze_process(p);
-				nr_user++;
 			} else {
-				/* Freeze only if the user space is frozen */
-				if (user_frozen)
-					freeze_process(p);
-				todo++;
+				if (freeze_user_space)
+					continue;
+
+				freeze_process(p);
 			}
+			todo++;
 		} while_each_thread(g, p);
 		read_unlock(&tasklist_lock);
-		todo += nr_user;
-		if (!user_frozen && !nr_user) {
-			sys_sync();
-			start_time = jiffies;
-		}
-		user_frozen = !nr_user;
 		yield();			/* Yield is okay here */
-		if (todo && time_after(jiffies, start_time + TIMEOUT))
+		if (todo && time_after(jiffies, end_time))
 			break;
-	} while(todo);
+	} while (todo);
 
-	/* This does not unfreeze processes that are already frozen
-	 * (we have slightly ugly calling convention in that respect,
-	 * and caller must call thaw_processes() if something fails),
-	 * but it cleans up leftover PF_FREEZE requests.
-	 */
 	if (todo) {
+		/* This does not unfreeze processes that are already frozen
+		 * (we have slightly ugly calling convention in that respect,
+		 * and caller must call thaw_processes() if something fails),
+		 * but it cleans up leftover PF_FREEZE requests.
+		 */
 		printk("\n");
-		printk(KERN_ERR "Stopping tasks timed out "
-			"after %d seconds (%d tasks remaining):\n",
-			TIMEOUT / HZ, todo);
+		printk(KERN_ERR "Stopping %s timed out after %d seconds "
+				"(%d tasks refusing to freeze):\n",
+				freeze_user_space ? "user space processes" :
+					"kernel threads",
+				TIMEOUT / HZ, todo);
 		read_lock(&tasklist_lock);
 		do_each_thread(g, p) {
+			if (is_user_space(p) == !freeze_user_space)
+				continue;
+
 			if (freezeable(p) && !frozen(p))
 				printk(KERN_ERR " %s\n", p->comm);
+
 			cancel_freezing(p);
 		} while_each_thread(g, p);
 		read_unlock(&tasklist_lock);
-		return todo;
 	}
 
+	return todo;
+}
+
+/**
+ *	freeze_processes - tell processes to enter the refrigerator
+ *
+ *	Returns 0 on success, or the number of processes that didn't freeze,
+ *	although they were told to.
+ */
+int freeze_processes(void)
+{
+	unsigned int nr_unfrozen;
+
+	printk("Stopping tasks ... ");
+	nr_unfrozen = try_to_freeze_tasks(FREEZER_USER_SPACE);
+	if (nr_unfrozen)
+		return nr_unfrozen;
+
+	sys_sync();
+	nr_unfrozen = try_to_freeze_tasks(FREEZER_KERNEL_THREADS);
+	if (nr_unfrozen)
+		return nr_unfrozen;
+
 	printk("done.\n");
 	BUG_ON(in_atomic());
 	return 0;
 }
 
-void thaw_processes(void)
+static void thaw_tasks(int thaw_user_space)
 {
 	struct task_struct *g, *p;
 
-	printk("Restarting tasks... ");
 	read_lock(&tasklist_lock);
 	do_each_thread(g, p) {
 		if (!freezeable(p))
 			continue;
+
+		if (is_user_space(p) == !thaw_user_space)
+			continue;
+
 		if (!thaw_process(p))
-			printk(KERN_INFO "Strange, %s not stopped\n", p->comm);
+			printk(KERN_WARNING " Strange, %s not stopped\n",
+				p->comm );
 	} while_each_thread(g, p);
-
 	read_unlock(&tasklist_lock);
+}
+
+void thaw_processes(void)
+{
+	printk("Restarting tasks ... ");
+	thaw_tasks(FREEZER_KERNEL_THREADS);
+	thaw_tasks(FREEZER_USER_SPACE);
 	schedule();
 	printk("done.\n");
 }