livepatch: Remove signal sysfs attribute

The fake signal is send automatically now. We can rely on it completely
and remove the sysfs attribute.

Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

3 files changed, 41 insertions, 74 deletions

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index adca5cf07f7e..fe1993399823 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -313,7 +313,6 @@ static int klp_write_object_relocations(struct module *pmod,
  * /sys/kernel/livepatch/<patch>
  * /sys/kernel/livepatch/<patch>/enabled
  * /sys/kernel/livepatch/<patch>/transition
- * /sys/kernel/livepatch/<patch>/signal
  * /sys/kernel/livepatch/<patch>/force
  * /sys/kernel/livepatch/<patch>/<object>
  * /sys/kernel/livepatch/<patch>/<object>/<function,sympos>
@@ -382,35 +381,6 @@ static ssize_t transition_show(struct kobject *kobj,
 			patch == klp_transition_patch);
 }
 
-static ssize_t signal_store(struct kobject *kobj, struct kobj_attribute *attr,
-			    const char *buf, size_t count)
-{
-	struct klp_patch *patch;
-	int ret;
-	bool val;
-
-	ret = kstrtobool(buf, &val);
-	if (ret)
-		return ret;
-
-	if (!val)
-		return count;
-
-	mutex_lock(&klp_mutex);
-
-	patch = container_of(kobj, struct klp_patch, kobj);
-	if (patch != klp_transition_patch) {
-		mutex_unlock(&klp_mutex);
-		return -EINVAL;
-	}
-
-	klp_send_signals();
-
-	mutex_unlock(&klp_mutex);
-
-	return count;
-}
-
 static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
 			   const char *buf, size_t count)
 {
@@ -442,12 +412,10 @@ static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
 
 static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled);
 static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition);
-static struct kobj_attribute signal_kobj_attr = __ATTR_WO(signal);
 static struct kobj_attribute force_kobj_attr = __ATTR_WO(force);
 static struct attribute *klp_patch_attrs[] = {
 	&enabled_kobj_attr.attr,
 	&transition_kobj_attr.attr,
-	&signal_kobj_attr.attr,
 	&force_kobj_attr.attr,
 	NULL
 };
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index ea7697bb753e..183b2086ba03 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -348,6 +348,47 @@ done:
 }
 
 /*
+ * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set.
+ * Kthreads with TIF_PATCH_PENDING set are woken up.
+ */
+static void klp_send_signals(void)
+{
+	struct task_struct *g, *task;
+
+	if (klp_signals_cnt == SIGNALS_TIMEOUT)
+		pr_notice("signaling remaining tasks\n");
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, task) {
+		if (!klp_patch_pending(task))
+			continue;
+
+		/*
+		 * There is a small race here. We could see TIF_PATCH_PENDING
+		 * set and decide to wake up a kthread or send a fake signal.
+		 * Meanwhile the task could migrate itself and the action
+		 * would be meaningless. It is not serious though.
+		 */
+		if (task->flags & PF_KTHREAD) {
+			/*
+			 * Wake up a kthread which sleeps interruptedly and
+			 * still has not been migrated.
+			 */
+			wake_up_state(task, TASK_INTERRUPTIBLE);
+		} else {
+			/*
+			 * Send fake signal to all non-kthread tasks which are
+			 * still not migrated.
+			 */
+			spin_lock_irq(&task->sighand->siglock);
+			signal_wake_up(task, 0);
+			spin_unlock_irq(&task->sighand->siglock);
+		}
+	}
+	read_unlock(&tasklist_lock);
+}
+
+/*
  * Try to switch all remaining tasks to the target patch state by walking the
  * stacks of sleeping tasks and looking for any to-be-patched or
  * to-be-unpatched functions.  If such functions are found, the task can't be
@@ -587,47 +628,6 @@ void klp_copy_process(struct task_struct *child)
 }
 
 /*
- * Sends a fake signal to all non-kthread tasks with TIF_PATCH_PENDING set.
- * Kthreads with TIF_PATCH_PENDING set are woken up.
- */
-void klp_send_signals(void)
-{
-	struct task_struct *g, *task;
-
-	if (klp_signals_cnt == SIGNALS_TIMEOUT)
-		pr_notice("signaling remaining tasks\n");
-
-	read_lock(&tasklist_lock);
-	for_each_process_thread(g, task) {
-		if (!klp_patch_pending(task))
-			continue;
-
-		/*
-		 * There is a small race here. We could see TIF_PATCH_PENDING
-		 * set and decide to wake up a kthread or send a fake signal.
-		 * Meanwhile the task could migrate itself and the action
-		 * would be meaningless. It is not serious though.
-		 */
-		if (task->flags & PF_KTHREAD) {
-			/*
-			 * Wake up a kthread which sleeps interruptedly and
-			 * still has not been migrated.
-			 */
-			wake_up_state(task, TASK_INTERRUPTIBLE);
-		} else {
-			/*
-			 * Send fake signal to all non-kthread tasks which are
-			 * still not migrated.
-			 */
-			spin_lock_irq(&task->sighand->siglock);
-			signal_wake_up(task, 0);
-			spin_unlock_irq(&task->sighand->siglock);
-		}
-	}
-	read_unlock(&tasklist_lock);
-}
-
-/*
  * Drop TIF_PATCH_PENDING of all tasks on admin's request. This forces an
  * existing transition to finish.
  *
diff --git a/kernel/livepatch/transition.h b/kernel/livepatch/transition.h
index f9d0bc016067..322db16233de 100644
--- a/kernel/livepatch/transition.h
+++ b/kernel/livepatch/transition.h
@@ -11,7 +11,6 @@ void klp_cancel_transition(void);
 void klp_start_transition(void);
 void klp_try_complete_transition(void);
 void klp_reverse_transition(void);
-void klp_send_signals(void);
 void klp_force_transition(void);
 
 #endif /* _LIVEPATCH_TRANSITION_H */