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USB: cdc-wdm: don't enable interrupts in USB-giveback

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In the code path
  __usb_hcd_giveback_urb()
  -> wdm_in_callback()
   -> service_outstanding_interrupt()

The function service_outstanding_interrupt() will unconditionally enable
interrupts during unlock and invoke usb_submit_urb() with GFP_KERNEL.
If the HCD completes in BH (like ehci does) then the context remains
atomic due local_bh_disable() and enabling interrupts does not change
this.

Defer the error case handling to a workqueue as suggested by Oliver
Neukum. In case of an error the worker performs the read out and wakes
the user.

Fixes: c1da59dad0 ("cdc-wdm: Clear read pipeline in case of error")
Cc: Robert Foss <robert.foss@collabora.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sebastian Andrzej Siewior 2018-06-14 18:36:46 +02:00 committed by Greg Kroah-Hartman
parent 4327059a14
commit 2df6948428
1 changed files with 24 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
drivers/usb/class/cdc-wdm.c
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@ -96,6 +96,7 @@ struct wdm_device {
struct mutex rlock;
wait_queue_head_t wait;
struct work_struct rxwork;
struct work_struct service_outs_intr;
int werr;
int rerr;
int resp_count;
@ -151,9 +152,6 @@ static void wdm_out_callback(struct urb *urb)
wake_up(&desc->wait);
}
/* forward declaration */
static int service_outstanding_interrupt(struct wdm_device *desc);
static void wdm_in_callback(struct urb *urb)
{
struct wdm_device *desc = urb->context;
@ -209,8 +207,6 @@ static void wdm_in_callback(struct urb *urb)
}
}
skip_error:
set_bit(WDM_READ, &desc->flags);
wake_up(&desc->wait);
if (desc->rerr) {
/*
@ -219,9 +215,11 @@ skip_error:
* We should respond to further attempts from the device to send
* data, so that we can get unstuck.
*/
service_outstanding_interrupt(desc);
schedule_work(&desc->service_outs_intr);
} else {
set_bit(WDM_READ, &desc->flags);
wake_up(&desc->wait);
}
spin_unlock(&desc->iuspin);
}
@ -758,6 +756,21 @@ static void wdm_rxwork(struct work_struct *work)
}
}
static void service_interrupt_work(struct work_struct *work)
{
struct wdm_device *desc;
desc = container_of(work, struct wdm_device, service_outs_intr);
spin_lock_irq(&desc->iuspin);
service_outstanding_interrupt(desc);
if (!desc->resp_count) {
set_bit(WDM_READ, &desc->flags);
wake_up(&desc->wait);
}
spin_unlock_irq(&desc->iuspin);
}
/* --- hotplug --- */
static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor *ep,
@ -779,6 +792,7 @@ static int wdm_create(struct usb_interface *intf, struct usb_endpoint_descriptor
desc->inum = cpu_to_le16((u16)intf->cur_altsetting->desc.bInterfaceNumber);
desc->intf = intf;
INIT_WORK(&desc->rxwork, wdm_rxwork);
INIT_WORK(&desc->service_outs_intr, service_interrupt_work);
rv = -EINVAL;
if (!usb_endpoint_is_int_in(ep))
@ -964,6 +978,7 @@ static void wdm_disconnect(struct usb_interface *intf)
mutex_lock(&desc->wlock);
kill_urbs(desc);
cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr);
mutex_unlock(&desc->wlock);
mutex_unlock(&desc->rlock);
@ -1006,6 +1021,7 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
/* callback submits work - order is essential */
kill_urbs(desc);
cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr);
}
if (!PMSG_IS_AUTO(message)) {
mutex_unlock(&desc->wlock);
@ -1065,6 +1081,7 @@ static int wdm_pre_reset(struct usb_interface *intf)
mutex_lock(&desc->wlock);
kill_urbs(desc);
cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr);
return 0;
}