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Bluetooth: bcm203x: Fix race condition on disconnect

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When disconnecting a bcm203x device we kill and destroy the usb-urb, however,
there might still be a pending work-structure which resubmits the now invalid
urb. To avoid this race condition, we simply set a shutdown-flag and
synchronously kill the worker first.

This also adds a comment to all schedule_work()s, as it is really not clear
that they are used as replacement for short timers (which can be seen in the git
history).

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This commit is contained in:
David Herrmann 2011-10-26 11:13:13 +02:00 committed by Gustavo F. Padovan
parent 52a1020e80
commit 844e4b76cc
1 changed files with 10 additions and 0 deletions
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10
drivers/bluetooth/bcm203x.c
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@ -24,6 +24,7 @@
#include <linux/module.h>
#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
@ -65,6 +66,7 @@ struct bcm203x_data {
unsigned long state;
struct work_struct work;
atomic_t shutdown;
struct urb *urb;
unsigned char *buffer;
@ -97,6 +99,7 @@ static void bcm203x_complete(struct urb *urb)
data->state = BCM203X_SELECT_MEMORY;
/* use workqueue to have a small delay */
schedule_work(&data->work);
break;
@ -155,6 +158,9 @@ static void bcm203x_work(struct work_struct *work)
struct bcm203x_data *data =
container_of(work, struct bcm203x_data, work);
if (atomic_read(&data->shutdown))
return;
if (usb_submit_urb(data->urb, GFP_ATOMIC) < 0)
BT_ERR("Can't submit URB");
}
@ -243,6 +249,7 @@ static int bcm203x_probe(struct usb_interface *intf, const struct usb_device_id
usb_set_intfdata(intf, data);
/* use workqueue to have a small delay */
schedule_work(&data->work);
return 0;
@ -254,6 +261,9 @@ static void bcm203x_disconnect(struct usb_interface *intf)
BT_DBG("intf %p", intf);
atomic_inc(&data->shutdown);
cancel_work_sync(&data->work);
usb_kill_urb(data->urb);
usb_set_intfdata(intf, NULL);