1 files changed, 67 insertions, 12 deletions

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 4706df20191b..49c6cbab984f 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -71,7 +71,7 @@ void tty_buffer_unlock_exclusive(struct tty_port *port)
 	atomic_dec(&buf->priority);
 	mutex_unlock(&buf->lock);
 	if (restart)
-		queue_work(system_unbound_wq, &buf->work);
+		queue_kthread_work(&port->worker, &buf->work);
 }
 EXPORT_SYMBOL_GPL(tty_buffer_unlock_exclusive);
 
@@ -132,6 +132,8 @@ void tty_buffer_free_all(struct tty_port *port)
 	buf->tail = &buf->sentinel;
 
 	atomic_set(&buf->mem_used, 0);
+	if (!IS_ERR_OR_NULL(port->worker_thread))
+		kthread_stop(port->worker_thread);
 }
 
 /**
@@ -166,7 +168,8 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size)
 	   have queued and recycle that ? */
 	if (atomic_read(&port->buf.mem_used) > port->buf.mem_limit)
 		return NULL;
-	p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
+	p = kmalloc(sizeof(struct tty_buffer) + 2 * size,
+		    GFP_ATOMIC | __GFP_NOWARN);
 	if (p == NULL)
 		return NULL;
 
@@ -387,6 +390,15 @@ int __tty_insert_flip_char(struct tty_port *port, unsigned char ch, char flag)
 }
 EXPORT_SYMBOL(__tty_insert_flip_char);
 
+static inline void tty_flip_buffer_commit(struct tty_buffer *tail)
+{
+	/*
+	 * Paired w/ acquire in flush_to_ldisc(); ensures flush_to_ldisc() sees
+	 * buffer data.
+	 */
+	smp_store_release(&tail->commit, tail->used);
+}
+
 /**
  *	tty_schedule_flip	-	push characters to ldisc
  *	@port: tty port to push from
@@ -400,11 +412,8 @@ void tty_schedule_flip(struct tty_port *port)
 {
 	struct tty_bufhead *buf = &port->buf;
 
-	/* paired w/ acquire in flush_to_ldisc(); ensures
-	 * flush_to_ldisc() sees buffer data.
-	 */
-	smp_store_release(&buf->tail->commit, buf->tail->used);
-	queue_work(system_unbound_wq, &buf->work);
+	tty_flip_buffer_commit(buf->tail);
+	queue_kthread_work(&port->worker, &buf->work);
 }
 EXPORT_SYMBOL(tty_schedule_flip);
 
@@ -472,7 +481,7 @@ receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count)
  *		 'consumer'
  */
 
-static void flush_to_ldisc(struct work_struct *work)
+static void flush_to_ldisc(struct kthread_work *work)
 {
 	struct tty_port *port = container_of(work, struct tty_port, buf.work);
 	struct tty_bufhead *buf = &port->buf;
@@ -519,6 +528,9 @@ static void flush_to_ldisc(struct work_struct *work)
 		if (!count)
 			break;
 		head->read += count;
+
+		if (need_resched())
+			cond_resched();
 	}
 
 	mutex_unlock(&buf->lock);
@@ -544,6 +556,37 @@ void tty_flip_buffer_push(struct tty_port *port)
 EXPORT_SYMBOL(tty_flip_buffer_push);
 
 /**
+ * tty_insert_flip_string_and_push_buffer - add characters to the tty buffer and
+ *	push
+ * @port: tty port
+ * @chars: characters
+ * @size: size
+ *
+ * The function combines tty_insert_flip_string() and tty_flip_buffer_push()
+ * with the exception of properly holding the @port->lock.
+ *
+ * To be used only internally (by pty currently).
+ *
+ * Returns: the number added.
+ */
+int tty_insert_flip_string_and_push_buffer(struct tty_port *port,
+		const unsigned char *chars, size_t size)
+{
+	struct tty_bufhead *buf = &port->buf;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	size = tty_insert_flip_string(port, chars, size);
+	if (size)
+		tty_flip_buffer_commit(buf->tail);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	queue_kthread_work(&port->worker, &buf->work);
+
+	return size;
+}
+
+/**
  *	tty_buffer_init		-	prepare a tty buffer structure
  *	@tty: tty to initialise
  *
@@ -562,8 +605,20 @@ void tty_buffer_init(struct tty_port *port)
 	init_llist_head(&buf->free);
 	atomic_set(&buf->mem_used, 0);
 	atomic_set(&buf->priority, 0);
-	INIT_WORK(&buf->work, flush_to_ldisc);
 	buf->mem_limit = TTYB_DEFAULT_MEM_LIMIT;
+	init_kthread_work(&buf->work, flush_to_ldisc);
+	init_kthread_worker(&port->worker);
+	port->worker_thread = kthread_run(kthread_worker_fn, &port->worker,
+					  "tty_worker_thread");
+	if (IS_ERR(port->worker_thread)) {
+		/*
+		 * Not good, we can't unwind, this tty is going to be really
+		 * sad...
+		 */
+		pr_err("Unable to start tty_worker_thread\n");
+	}
+
+
 }
 
 /**
@@ -591,15 +646,15 @@ void tty_buffer_set_lock_subclass(struct tty_port *port)
 
 bool tty_buffer_restart_work(struct tty_port *port)
 {
-	return queue_work(system_unbound_wq, &port->buf.work);
+	return queue_kthread_work(&port->worker, &port->buf.work);
 }
 
 bool tty_buffer_cancel_work(struct tty_port *port)
 {
-	return cancel_work_sync(&port->buf.work);
+	return kthread_cancel_work_sync(&port->buf.work);
 }
 
 void tty_buffer_flush_work(struct tty_port *port)
 {
-	flush_work(&port->buf.work);
+	flush_kthread_work(&port->buf.work);
 }