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Commit 922a5ead authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
Browse files

usb: cdc-wdm: Fix race between autosuspend and reading from the device 



While an available response is read the device must not
be autosuspended. This requires a flag dedicated to that
purpose.

Signed-off-by: default avatarOliver Neukum <neukum@b1-systems.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 860e41a7

drivers/usb/class/cdc-wdm.c

+10 −4
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids); 
#define WDM_READ		4

#define WDM_INT_STALL		5

#define WDM_POLL_RUNNING	6

#define WDM_RESPONDING		7





#define WDM_MAX			16
@@ -115,21 +116,22 @@ static void wdm_in_callback(struct urb *urb) 
	int status = urb->status;



	spin_lock(&desc->iuspin);

	clear_bit(WDM_RESPONDING, &desc->flags);



	if (status) {

		switch (status) {

		case -ENOENT:

			dev_dbg(&desc->intf->dev,

				"nonzero urb status received: -ENOENT");

			break;

			goto skip_error;

		case -ECONNRESET:

			dev_dbg(&desc->intf->dev,

				"nonzero urb status received: -ECONNRESET");

			break;

			goto skip_error;

		case -ESHUTDOWN:

			dev_dbg(&desc->intf->dev,

				"nonzero urb status received: -ESHUTDOWN");

			break;

			goto skip_error;

		case -EPIPE:

			dev_err(&desc->intf->dev,

				"nonzero urb status received: -EPIPE\n");
@@ -145,6 +147,7 @@ static void wdm_in_callback(struct urb *urb) 
	desc->reslength = urb->actual_length;

	memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);

	desc->length += desc->reslength;

skip_error:

	wake_up(&desc->wait);



	set_bit(WDM_READ, &desc->flags);
@@ -227,6 +230,7 @@ static void wdm_int_callback(struct urb *urb) 
	desc->response->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

	spin_lock(&desc->iuspin);

	clear_bit(WDM_READ, &desc->flags);

	set_bit(WDM_RESPONDING, &desc->flags);

	if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {

		rv = usb_submit_urb(desc->response, GFP_ATOMIC);

		dev_dbg(&desc->intf->dev, "%s: usb_submit_urb %d",
@@ -234,6 +238,7 @@ static void wdm_int_callback(struct urb *urb) 
	}

	spin_unlock(&desc->iuspin);

	if (rv < 0) {

		clear_bit(WDM_RESPONDING, &desc->flags);

		if (rv == -EPERM)

			return;

		if (rv == -ENOMEM) {
@@ -795,7 +800,8 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message) 
	mutex_lock(&desc->lock);

#ifdef CONFIG_PM

	if ((message.event & PM_EVENT_AUTO) &&

			test_bit(WDM_IN_USE, &desc->flags)) {

			(test_bit(WDM_IN_USE, &desc->flags)

			|| test_bit(WDM_RESPONDING, &desc->flags))) {

		rv = -EBUSY;

	} else {

#endif