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usb: cdc-wdm: make reset work with blocking IO

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Add a flag to tell wdm_read/wdm_write that a reset is in progress,
and wake any blocking read/write before taking the mutexes.  This
allows the device to reset without waiting for blocking IO to
finish.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Bjørn Mork 2012-02-10 09:44:08 +01:00 committed by Greg Kroah-Hartman
parent 7483948fdd
commit 8804420275
1 changed files with 17 additions and 4 deletions
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21
drivers/usb/class/cdc-wdm.c
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@ -70,6 +70,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids);
#define WDM_POLL_RUNNING 6
#define WDM_RESPONDING 7
#define WDM_SUSPENDING 8
#define WDM_RESETTING 9
#define WDM_MAX 16
@ -340,6 +341,10 @@ static ssize_t wdm_write
else
if (test_bit(WDM_IN_USE, &desc->flags))
r = -EAGAIN;
if (test_bit(WDM_RESETTING, &desc->flags))
r = -EIO;
if (r < 0) {
kfree(buf);
goto out;
@ -419,6 +424,10 @@ retry:
rv = -ENODEV;
goto err;
}
if (test_bit(WDM_RESETTING, &desc->flags)) {
rv = -EIO;
goto err;
}
usb_mark_last_busy(interface_to_usbdev(desc->intf));
if (rv < 0) {
rv = -ERESTARTSYS;
@ -859,10 +868,6 @@ static int wdm_pre_reset(struct usb_interface *intf)
{
struct wdm_device *desc = usb_get_intfdata(intf);
mutex_lock(&desc->rlock);
mutex_lock(&desc->wlock);
kill_urbs(desc);
/*
* we notify everybody using poll of
* an exceptional situation
@ -870,9 +875,16 @@ static int wdm_pre_reset(struct usb_interface *intf)
* message from the device is lost
*/
spin_lock_irq(&desc->iuspin);
set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
set_bit(WDM_READ, &desc->flags); /* unblock read */
clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
desc->rerr = -EINTR;
spin_unlock_irq(&desc->iuspin);
wake_up_all(&desc->wait);
mutex_lock(&desc->rlock);
mutex_lock(&desc->wlock);
kill_urbs(desc);
cancel_work_sync(&desc->rxwork);
return 0;
}
@ -881,6 +893,7 @@ static int wdm_post_reset(struct usb_interface *intf)
struct wdm_device *desc = usb_get_intfdata(intf);
int rv;
clear_bit(WDM_RESETTING, &desc->flags);
rv = recover_from_urb_loss(desc);
mutex_unlock(&desc->wlock);
mutex_unlock(&desc->rlock);