USB: add urb->unlinked field

This patch (as970) adds a new urb->unlinked field, which is used to
store the status of unlinked URBs since we can't use urb->status for
that purpose any more.  To help simplify the HCDs, usbcore will check
urb->unlinked before calling the completion handler; if the value is
set it will automatically override the status reported by the HCD.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
CC: Olav Kongas <ok@artecdesign.ee>
CC: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
CC: Tony Olech <tony.olech@elandigitalsystems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hcd.c

@@ -532,8 +532,7 @@ static int rh_call_control (struct usb_hcd *hcd, struct urb *urb)
 
 	/* any errors get returned through the urb completion */
 	spin_lock_irq(&hcd_root_hub_lock);
-	if (urb->status == -EINPROGRESS)
-		urb->status = status;
+	urb->status = status;
 	usb_hcd_unlink_urb_from_ep(hcd, urb);
 
 	/* This peculiar use of spinlocks echoes what real HC drivers do.
@@ -1024,6 +1023,7 @@ int usb_hcd_link_urb_to_ep(struct usb_hcd *hcd, struct urb *urb)
 	switch (hcd->state) {
 	case HC_STATE_RUNNING:
 	case HC_STATE_RESUMING:
+		urb->unlinked = 0;
 		list_add_tail(&urb->urb_list, &urb->ep->urb_list);
 		break;
 	default:
@@ -1071,9 +1071,9 @@ int usb_hcd_check_unlink_urb(struct usb_hcd *hcd, struct urb *urb,
 	/* Any status except -EINPROGRESS means something already started to
 	 * unlink this URB from the hardware.  So there's no more work to do.
 	 */
-	if (urb->status != -EINPROGRESS)
+	if (urb->unlinked)
 		return -EBUSY;
-	urb->status = status;
+	urb->unlinked = status;
 
 	/* IRQ setup can easily be broken so that USB controllers
 	 * never get completion IRQs ... maybe even the ones we need to
@@ -1259,6 +1259,10 @@ int usb_hcd_unlink_urb (struct urb *urb, int status)
  * (and is done using urb->hcpriv).  It also released all HCD locks;
  * the device driver won't cause problems if it frees, modifies,
  * or resubmits this URB.
+ *
+ * If @urb was unlinked, the value of @urb->status will be overridden by
+ * @urb->unlinked.  Erroneous short transfers are detected in case
+ * the HCD hasn't checked for them.
  */
 void usb_hcd_giveback_urb (struct usb_hcd *hcd, struct urb *urb)
 {
@@ -1266,7 +1270,9 @@ void usb_hcd_giveback_urb (struct usb_hcd *hcd, struct urb *urb)
 	usbmon_urb_complete (&hcd->self, urb);
 	usb_unanchor_urb(urb);
 	urb->hcpriv = NULL;
-	if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) &&
+	if (unlikely(urb->unlinked))
+		urb->status = urb->unlinked;
+	else if (unlikely((urb->transfer_flags & URB_SHORT_NOT_OK) &&
 			urb->actual_length < urb->transfer_buffer_length &&
 			!urb->status))
 		urb->status = -EREMOTEIO;
@@ -1305,8 +1311,7 @@ void usb_hcd_endpoint_disable (struct usb_device *udev,
 	list_for_each_entry (urb, &ep->urb_list, urb_list) {
 		int	is_in;
 
-		/* the urb may already have been unlinked */
-		if (urb->status != -EINPROGRESS)
+		if (urb->unlinked)
 			continue;
 		usb_get_urb (urb);
 		is_in = usb_urb_dir_in(urb);

drivers/usb/gadget/dummy_hcd.c

@@ -1029,8 +1029,7 @@ static int dummy_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 static void maybe_set_status (struct urb *urb, int status)
 {
 	spin_lock (&urb->lock);
-	if (urb->status == -EINPROGRESS)
-		urb->status = status;
+	urb->status = status;
 	spin_unlock (&urb->lock);
 }
 
@@ -1257,10 +1256,9 @@ static void dummy_timer (unsigned long _dum)
 		int			type;
 
 		urb = urbp->urb;
-		if (urb->status != -EINPROGRESS) {
-			/* likely it was just unlinked */
+		if (urb->unlinked)
 			goto return_urb;
-		} else if (dum->rh_state != DUMMY_RH_RUNNING)
+		else if (dum->rh_state != DUMMY_RH_RUNNING)
 			continue;
 		type = usb_pipetype (urb->pipe);
 

drivers/usb/host/ehci-q.c

@@ -151,7 +151,7 @@ static void qtd_copy_status (
 		urb->actual_length += length - QTD_LENGTH (token);
 
 	/* don't modify error codes */
-	if (unlikely (urb->status != -EINPROGRESS))
+	if (unlikely(urb->unlinked))
 		return;
 
 	/* force cleanup after short read; not always an error */
@@ -232,21 +232,14 @@ __acquires(ehci->lock)
 	}
 
 	spin_lock (&urb->lock);
-	switch (urb->status) {
-	case -EINPROGRESS:		/* success */
-		urb->status = 0;
-	default:			/* fault */
-		COUNT (ehci->stats.complete);
-		break;
-	case -EREMOTEIO:		/* fault or normal */
-		if (!(urb->transfer_flags & URB_SHORT_NOT_OK))
+	if (unlikely(urb->unlinked)) {
+		COUNT(ehci->stats.unlink);
+	} else {
+		if (likely(urb->status == -EINPROGRESS ||
+				(urb->status == -EREMOTEIO &&
+				 !(urb->transfer_flags & URB_SHORT_NOT_OK))))
 			urb->status = 0;
-		COUNT (ehci->stats.complete);
-		break;
-	case -ECONNRESET:		/* canceled */
-	case -ENOENT:
-		COUNT (ehci->stats.unlink);
-		break;
+		COUNT(ehci->stats.complete);
 	}
 	spin_unlock (&urb->lock);
 
@@ -364,7 +357,8 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 			 * for the urb faulted (including short read) or
 			 * its urb was canceled.  we may patch qh or qtds.
 			 */
-			if (likely (urb->status == -EINPROGRESS))
+			if (likely(urb->status == -EINPROGRESS &&
+					!urb->unlinked))
 				continue;
 
 			/* issue status after short control reads */
@@ -395,7 +389,8 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 		spin_lock (&urb->lock);
 		qtd_copy_status (ehci, urb, qtd->length, token);
 		if (unlikely(urb->status == -EREMOTEIO)) {
-			do_status = usb_pipecontrol(urb->pipe);
+			do_status = (!urb->unlinked &&
+					usb_pipecontrol(urb->pipe));
 			urb->status = 0;
 		}
 		spin_unlock (&urb->lock);

drivers/usb/host/isp116x-hcd.c

@@ -455,11 +455,10 @@ static void postproc_atl_queue(struct isp116x *isp116x)
  done:
 		if (status != -EINPROGRESS) {
 			spin_lock(&urb->lock);
-			if (urb->status == -EINPROGRESS)
-				urb->status = status;
+			urb->status = status;
 			spin_unlock(&urb->lock);
 		}
-		if (urb->status != -EINPROGRESS)
+		if (urb->status != -EINPROGRESS || urb->unlinked)
 			finish_request(isp116x, ep, urb);
 	}
 }

drivers/usb/host/ohci-q.c

@@ -758,8 +758,7 @@ static void td_done (struct ohci_hcd *ohci, struct urb *urb, struct td *td)
 			cc = TD_CC_NOERROR;
 		if (cc != TD_CC_NOERROR && cc < 0x0E) {
 			spin_lock (&urb->lock);
-			if (urb->status == -EINPROGRESS)
-				urb->status = cc_to_error [cc];
+			urb->status = cc_to_error[cc];
 			spin_unlock (&urb->lock);
 		}
 
@@ -972,7 +971,7 @@ finish_unlinks (struct ohci_hcd *ohci, u16 tick)
 			urb = td->urb;
 			urb_priv = td->urb->hcpriv;
 
-			if (urb->status == -EINPROGRESS) {
+			if (!urb->unlinked) {
 				prev = &td->hwNextTD;
 				continue;
 			}

drivers/usb/host/r8a66597-hcd.c

@@ -1118,7 +1118,7 @@ __releases(r8a66597->lock) __acquires(r8a66597->lock)
 	r8a66597->timeout_map &= ~(1 << pipenum);
 
 	if (likely(td)) {
-		if (td->set_address && urb->status != 0)
+		if (td->set_address && (urb->status != 0 || urb->unlinked))
 			r8a66597->address_map &= ~(1 << urb->setup_packet[2]);
 
 		pipe_toggle_save(r8a66597, td->pipe, urb);
@@ -1225,8 +1225,7 @@ static void packet_read(struct r8a66597 *r8a66597, u16 pipenum)
 	}
 
 	if (finish && pipenum != 0) {
-		if (td->urb->status == -EINPROGRESS)
-			td->urb->status = status;
+		td->urb->status = status;
 		finish_request(r8a66597, td, pipenum, urb);
 	}
 }
@@ -1308,32 +1307,24 @@ static void check_next_phase(struct r8a66597 *r8a66597)
 	switch (td->type) {
 	case USB_PID_IN:
 	case USB_PID_OUT:
-		if (urb->status != -EINPROGRESS) {
-			finish = 1;
-			break;
-		}
 		if (check_transfer_finish(td, urb))
 			td->type = USB_PID_ACK;
 		break;
 	case USB_PID_SETUP:
-		if (urb->status != -EINPROGRESS)
-			finish = 1;
-		else if (urb->transfer_buffer_length == urb->actual_length) {
+		if (urb->transfer_buffer_length == urb->actual_length)
 			td->type = USB_PID_ACK;
-			urb->status = 0;
-		} else if (usb_pipeout(urb->pipe))
+		else if (usb_pipeout(urb->pipe))
 			td->type = USB_PID_OUT;
 		else
 			td->type = USB_PID_IN;
 		break;
 	case USB_PID_ACK:
 		finish = 1;
-		if (urb->status == -EINPROGRESS)
-			urb->status = 0;
+		urb->status = 0;
 		break;
 	}
 
-	if (finish)
+	if (finish || urb->unlinked)
 		finish_request(r8a66597, td, 0, urb);
 	else
 		start_transfer(r8a66597, td);
@@ -1418,8 +1409,7 @@ static void irq_pipe_empty(struct r8a66597 *r8a66597)
 			if ((tmp & INBUFM) == 0) {
 				disable_irq_empty(r8a66597, pipenum);
 				pipe_irq_disable(r8a66597, pipenum);
-				if (td->urb->status == -EINPROGRESS)
-					td->urb->status = 0;
+				td->urb->status = 0;
 				finish_request(r8a66597, td, pipenum, td->urb);
 			}
 		}

drivers/usb/host/sl811-hcd.c

@@ -436,8 +436,7 @@ static void finish_request(
 		ep->nextpid = USB_PID_SETUP;
 
 	spin_lock(&urb->lock);
-	if (urb->status == -EINPROGRESS)
-		urb->status = status;
+	urb->status = status;
 	spin_unlock(&urb->lock);
 
 	usb_hcd_unlink_urb_from_ep(sl811_to_hcd(sl811), urb);
@@ -598,7 +597,7 @@ done(struct sl811 *sl811, struct sl811h_ep *ep, u8 bank)
 				bank, status, ep, urbstat);
 	}
 
-	if (urb && (urbstat != -EINPROGRESS || urb->status != -EINPROGRESS))
+	if (urb && (urbstat != -EINPROGRESS || urb->unlinked))
 		finish_request(sl811, ep, urb, urbstat);
 }
 

drivers/usb/host/uhci-debug.c

@@ -120,8 +120,8 @@ static int uhci_show_urbp(struct urb_priv *urbp, char *buf, int len, int space)
 	out += sprintf(out, "%s%s", ptype, (urbp->fsbr ? " FSBR" : ""));
 	out += sprintf(out, " Actlen=%d", urbp->urb->actual_length);
 
-	if (urbp->urb->status != -EINPROGRESS)
-		out += sprintf(out, " Status=%d", urbp->urb->status);
+	if (urbp->urb->unlinked)
+		out += sprintf(out, " Unlinked=%d", urbp->urb->unlinked);
 	out += sprintf(out, "\n");
 
 	i = nactive = ninactive = 0;

drivers/usb/host/uhci-q.c

@@ -1557,15 +1557,12 @@ static void uhci_scan_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)
 			break;
 
 		spin_lock(&urb->lock);
-		if (urb->status == -EINPROGRESS)	/* Not dequeued */
-			urb->status = status;
-		else
-			status = ECONNRESET;		/* Not -ECONNRESET */
+		urb->status = status;
 		spin_unlock(&urb->lock);
 
 		/* Dequeued but completed URBs can't be given back unless
 		 * the QH is stopped or has finished unlinking. */
-		if (status == ECONNRESET) {
+		if (urb->unlinked) {
 			if (QH_FINISHED_UNLINKING(qh))
 				qh->is_stopped = 1;
 			else if (!qh->is_stopped)
@@ -1588,7 +1585,7 @@ static void uhci_scan_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)
 restart:
 	list_for_each_entry(urbp, &qh->queue, node) {
 		urb = urbp->urb;
-		if (urb->status != -EINPROGRESS) {
+		if (urb->unlinked) {
 
 			/* Fix up the TD links and save the toggles for
 			 * non-Isochronous queues.  For Isochronous queues,

include/linux/usb.h

@@ -1245,6 +1245,7 @@ struct urb
 	void *hcpriv;			/* private data for host controller */
 	atomic_t use_count;		/* concurrent submissions counter */
 	u8 reject;			/* submissions will fail */
+	int unlinked;			/* unlink error code */
 
 	/* public: documented fields in the urb that can be used by drivers */
 	struct list_head urb_list;	/* list head for use by the urb's