We need to ensure that no URBs are submitted during reset. Taking any of
the mutexes can deadlock against either wdm_read or wdm_write. Use the
WDM_SUSPENDING flag instead to indicate that no IO is possible, as the
requirements for suspend and reset are similar
Signed-off-by: Bjørn Mork <bjorn@xxxxxxx>
---
How about something like this? I don't think we need a new dedicated flag
as the semantics are the same for suspend. But maybe it should be renamed?
I've also added the cancel_work_sync() call which is in suspend, as I
believe that is necessary to avoid submitting any URBs.
Should this go to stable as well? It won't apply directly due to the
read/write mutex lock split, but I can prepare a patch.
Bjørn
drivers/usb/class/cdc-wdm.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index f63601a..64778df 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -859,10 +859,6 @@ 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
@@ -870,8 +866,11 @@ static int wdm_pre_reset(struct usb_interface *intf)
* message from the device is lost
*/
spin_lock_irq(&desc->iuspin);
+ set_bit(WDM_SUSPENDING, &desc->flags);
desc->rerr = -EINTR;
spin_unlock_irq(&desc->iuspin);
+ kill_urbs(desc);
+ cancel_work_sync(&desc->rxwork);
wake_up_all(&desc->wait);
return 0;
}
@@ -881,9 +880,8 @@ static int wdm_post_reset(struct usb_interface *intf)
struct wdm_device *desc = usb_get_intfdata(intf);
int rv;
+ clear_bit(WDM_SUSPENDING, &desc->flags);
rv = recover_from_urb_loss(desc);
- mutex_unlock(&desc->wlock);
- mutex_unlock(&desc->rlock);
return 0;
}
--
1.7.8.3
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