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hvcs: Synchronize hotplug remove with port free

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Synchronizes hotplug remove with the freeing of the port.
This ensures we have freed all the memory associated with
this port and are not leaking memory.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20230203155802.404324-6-brking@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Brian King 2023-02-03 09:58:02 -06:00 committed by Greg Kroah-Hartman
parent d432228bc7
commit 28d49f8cbe
1 changed files with 15 additions and 11 deletions
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26
drivers/tty/hvc/hvcs.c
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@ -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);
@ -663,11 +665,13 @@ 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));
@ -687,6 +691,7 @@ 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);
@ -694,6 +699,8 @@ 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 = {
@ -792,6 +799,7 @@ 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;
@ -799,16 +807,11 @@ static void hvcs_remove(struct vio_dev *dev)
spin_lock_irqsave(&hvcsd->lock, flags);
hvcsd->destroyed = &comp;
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);
/*
* The tty should always be valid at this time unless a
* simultaneous tty close already cleaned up the hvcs_struct.
@ -818,6 +821,8 @@ 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);
};
@ -1171,7 +1176,10 @@ 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);
@ -1227,11 +1235,7 @@ 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