[PATCH 0/6] hvcs: Various hvcs device hotplug fixes

@@ -1519,6 +1519,8 @@ static int __init hvcs_module_init(void)
 
 static void __exit hvcs_module_exit(void)
 {
+	driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan);
+
 	/*
 	 * This driver receives hvcs_remove callbacks for each device upon
 	 * module removal.

@@ -1538,8 +1540,6 @@ static void __exit hvcs_module_exit(void)
 	hvcs_pi_buff = NULL;
 	spin_unlock(&hvcs_pi_lock);
 
-	driver_remove_file(&hvcs_vio_driver.driver, &driver_attr_rescan);
-
 	tty_unregister_driver(hvcs_tty_driver);
 
 	hvcs_free_index_list();

@@ -802,7 +802,7 @@ static void hvcs_remove(struct vio_dev *dev)
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
 
-	tty = hvcsd->port.tty;
+	tty = tty_port_tty_get(&hvcsd->port);
 
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
 

@@ -819,8 +819,10 @@ static void hvcs_remove(struct vio_dev *dev)
 	 * hvcs_hangup.  The tty should always be valid at this time unless a
 	 * simultaneous tty close already cleaned up the hvcs_struct.
 	 */
-	if (tty)
+	if (tty) {
 		tty_hangup(tty);
+		tty_kref_put(tty);
+	}
 
 	printk(KERN_INFO "HVCS: vty-server@%X removed from the"
 			" vio bus.\n", dev->unit_address);

@@ -1215,12 +1215,9 @@ static void hvcs_hangup(struct tty_struct * tty)
 {
 	struct hvcs_struct *hvcsd = tty->driver_data;
 	unsigned long flags;
-	int temp_open_count;
 	int irq;
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
-	/* Preserve this so that we know how many kref refs to put */
-	temp_open_count = hvcsd->port.count;
 
 	/*
 	 * Don't kref put inside the spinlock because the destruction

@@ -1247,21 +1244,6 @@ static void hvcs_hangup(struct tty_struct * tty)
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
 
 	free_irq(irq, hvcsd);
-
-	/*
-	 * We need to kref_put() for every open_count we have since the
-	 * tty_hangup() function doesn't invoke a close per open connection on a
-	 * non-console device.
-	 */
-	while(temp_open_count) {
-		--temp_open_count;
-		/*
-		 * The final put will trigger destruction of the hvcs_struct.
-		 * NOTE:  If this hangup was signaled from user space then the
-		 * final put will never happen.
-		 */
-		tty_port_put(&hvcsd->port);
-	}
 }
 
 /*

@@ -688,8 +688,6 @@ static void hvcs_destruct_port(struct tty_port *p)
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
 	spin_unlock(&hvcs_structs_lock);
 
-	sysfs_remove_group(&vdev->dev.kobj, &hvcs_attr_group);
-
 	kfree(hvcsd);
 }
 

@@ -814,6 +812,8 @@ static void hvcs_remove(struct vio_dev *dev)
 	 */
 	tty_port_put(&hvcsd->port);
 
+	sysfs_remove_group(&dev->dev.kobj, &hvcs_attr_group);
+
 	/*
 	 * The hangup is a scheduled function which will auto chain call
 	 * hvcs_hangup.  The tty should always be valid at this time unless a

@@ -815,12 +815,11 @@ static void hvcs_remove(struct vio_dev *dev)
 	sysfs_remove_group(&dev->dev.kobj, &hvcs_attr_group);
 
 	/*
-	 * The hangup is a scheduled function which will auto chain call
-	 * hvcs_hangup.  The tty should always be valid at this time unless a
+	 * The tty should always be valid at this time unless a
 	 * simultaneous tty close already cleaned up the hvcs_struct.
 	 */
 	if (tty) {
-		tty_hangup(tty);
+		tty_vhangup(tty);
 		tty_kref_put(tty);
 	}
 

@@ -52,6 +52,7 @@
 
 #include <linux/device.h>
 #include <linux/init.h>
+#include <linux/completion.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/kref.h>

@@ -285,6 +286,7 @@ struct hvcs_struct {
 	char p_location_code[HVCS_CLC_LENGTH + 1]; /* CLC + Null Term */
 	struct list_head next; /* list management */
 	struct vio_dev *vdev;
+	struct completion *destroyed;
 };
 
 static LIST_HEAD(hvcs_structs);

@@ -658,11 +660,13 @@ static void hvcs_destruct_port(struct tty_port *p)
 {
 	struct hvcs_struct *hvcsd = container_of(p, struct hvcs_struct, port);
 	struct vio_dev *vdev;
+	struct completion *comp;
 	unsigned long flags;
 
 	spin_lock(&hvcs_structs_lock);
 	spin_lock_irqsave(&hvcsd->lock, flags);
 
+	comp = hvcsd->destroyed;
 	/* the list_del poisons the pointers */
 	list_del(&(hvcsd->next));
 

@@ -682,6 +686,7 @@ static void hvcs_destruct_port(struct tty_port *p)
 
 	hvcsd->p_unit_address = 0;
 	hvcsd->p_partition_ID = 0;
+	hvcsd->destroyed = NULL;
 	hvcs_return_index(hvcsd->index);
 	memset(&hvcsd->p_location_code[0], 0x00, HVCS_CLC_LENGTH + 1);
 

@@ -689,6 +694,8 @@ static void hvcs_destruct_port(struct tty_port *p)
 	spin_unlock(&hvcs_structs_lock);
 
 	kfree(hvcsd);
+	if (comp)
+		complete(comp);
 }
 
 static const struct tty_port_operations hvcs_port_ops = {

@@ -795,6 +802,7 @@ static int hvcs_probe(
 static void hvcs_remove(struct vio_dev *dev)
 {
 	struct hvcs_struct *hvcsd = dev_get_drvdata(&dev->dev);
+	DECLARE_COMPLETION_ONSTACK(comp);
 	unsigned long flags;
 	struct tty_struct *tty;
 

@@ -802,16 +810,11 @@ static void hvcs_remove(struct vio_dev *dev)
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
 
+	hvcsd->destroyed = ∁
 	tty = tty_port_tty_get(&hvcsd->port);
 
 	spin_unlock_irqrestore(&hvcsd->lock, flags);
 
-	/*
-	 * Let the last holder of this object cause it to be removed, which
-	 * would probably be tty_hangup below.
-	 */
-	tty_port_put(&hvcsd->port);
-
 	sysfs_remove_group(&dev->dev.kobj, &hvcs_attr_group);
 
 	/*

@@ -823,6 +826,8 @@ static void hvcs_remove(struct vio_dev *dev)
 		tty_kref_put(tty);
 	}
 
+	tty_port_put(&hvcsd->port);
+	wait_for_completion(&comp);
 	printk(KERN_INFO "HVCS: vty-server@%X removed from the"
 			" vio bus.\n", dev->unit_address);
 };

@@ -1172,7 +1177,10 @@ static void hvcs_close(struct tty_struct *tty, struct file *filp)
 	hvcsd = tty->driver_data;
 
 	spin_lock_irqsave(&hvcsd->lock, flags);
-	if (--hvcsd->port.count == 0) {
+	if (hvcsd->port.count == 0) {
+		spin_unlock_irqrestore(&hvcsd->lock, flags);
+		return;
+	} else if (--hvcsd->port.count == 0) {
 
 		vio_disable_interrupts(hvcsd->vdev);
 

@@ -1228,11 +1236,7 @@ static void hvcs_hangup(struct tty_struct * tty)
 	vio_disable_interrupts(hvcsd->vdev);
 
 	hvcsd->todo_mask = 0;
-
-	/* I don't think the tty needs the hvcs_struct pointer after a hangup */
-	tty->driver_data = NULL;
 	hvcsd->port.tty = NULL;
-
 	hvcsd->port.count = 0;
 
 	/* This will drop any buffered data on the floor which is OK in a hangup