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Commit ecdc0a59 authored by Franck Bui-Huu's avatar Franck Bui-Huu Committed by Greg Kroah-Hartman
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USB: usbcore get rid of the timer in usb_start_wait_urb() 



This patch uses completion timeout instead of a timer to implement
a timeout when submitting an URB in usb_start_wait_urb().

It also fixes a small issue. With the previous code, if no timeout
happened and the URB's status was set to ECONNRESET value, the code
assumed wrongly that a timeout had occured.

Signed-off-by: default avatarFranck Bui-Huu <vagabon.xyz@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 014aa2a3

drivers/usb/core/message.c

+29 −44
Original line number Diff line number Diff line
@@ -23,59 +23,44 @@ static void usb_api_blocking_completion(struct urb *urb, struct pt_regs *regs) 
}





static void timeout_kill(unsigned long data)

{

	struct urb	*urb = (struct urb *) data;



	usb_unlink_urb(urb);

}



// Starts urb and waits for completion or timeout

// note that this call is NOT interruptible, while

// many device driver i/o requests should be interruptible

/*

 * Starts urb and waits for completion or timeout. Note that this call

 * is NOT interruptible. Many device driver i/o requests should be

 * interruptible and therefore these drivers should implement their

 * own interruptible routines.

 */

static int usb_start_wait_urb(struct urb *urb, int timeout, int *actual_length)

{ 

	struct completion done;

	struct timer_list	timer;

	unsigned long expire;

	int status;



	init_completion(&done); 	

	urb->context = &done;

	urb->actual_length = 0;

	status = usb_submit_urb(urb, GFP_NOIO);

	if (unlikely(status))

		goto out;



	expire = timeout ? msecs_to_jiffies(timeout) : MAX_SCHEDULE_TIMEOUT;

	if (!wait_for_completion_timeout(&done, expire)) {



	if (status == 0) {

		if (timeout > 0) {

			init_timer(&timer);

			timer.expires = jiffies + msecs_to_jiffies(timeout);

			timer.data = (unsigned long)urb;

			timer.function = timeout_kill;

			/* grr.  timeout _should_ include submit delays. */

			add_timer(&timer);

		}

		wait_for_completion(&done);

		status = urb->status;

		/* note:  HCDs return ETIMEDOUT for other reasons too */

		if (status == -ECONNRESET) {

		dev_dbg(&urb->dev->dev,

			"%s timed out on ep%d%s len=%d/%d\n",

			current->comm,

			usb_pipeendpoint(urb->pipe),

			usb_pipein(urb->pipe) ? "in" : "out",

			urb->actual_length,

				urb->transfer_buffer_length

				);

			if (urb->actual_length > 0)

				status = 0;

			else

				status = -ETIMEDOUT;

		}

		if (timeout > 0)

			del_timer_sync(&timer);

	}

			urb->transfer_buffer_length);



		usb_kill_urb(urb);

		status = urb->status == -ENOENT ? -ETIMEDOUT : urb->status;

	} else

		status = urb->status;

out:

	if (actual_length)

		*actual_length = urb->actual_length;



	usb_free_urb(urb);

	return status;

}