USB: avoid the donelist after an error in ohci-hcd

This patch (as972) changes ohci-hcd so that after an error occurs, the
remaining TDs for the URB will be skipped over entirely instead of
going through the donelist.  This enables the driver to give back the
URB as soon as the error is detected, avoiding the need to store the
error status in urb->status.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 8 insertions, 16 deletions

diff --git a/drivers/usb/host/ohci-q.c b/drivers/usb/host/ohci-q.c
index 3c793fa..860e55f 100644
--- a/drivers/usb/host/ohci-q.c
+++ b/drivers/usb/host/ohci-q.c
@@ -783,10 +783,10 @@ static void td_done (struct ohci_hcd *ohci, struct urb *urb, struct td *td)
 
 /*-------------------------------------------------------------------------*/
 
-static inline struct td *
-ed_halted (struct ohci_hcd *ohci, struct td *td, int cc, struct td *rev)
+static void ed_halted(struct ohci_hcd *ohci, struct td *td, int cc)
 {
 	struct urb		*urb = td->urb;
+	urb_priv_t		*urb_priv = urb->hcpriv;
 	struct ed		*ed = td->ed;
 	struct list_head	*tmp = td->td_list.next;
 	__hc32			toggle = ed->hwHeadP & cpu_to_hc32 (ohci, ED_C);
@@ -798,13 +798,12 @@ ed_halted (struct ohci_hcd *ohci, struct td *td, int cc, struct td *rev)
 	wmb ();
 	ed->hwHeadP &= ~cpu_to_hc32 (ohci, ED_H);
 
-	/* put any later tds from this urb onto the donelist, after 'td',
-	 * order won't matter here: no errors, and nothing was transferred.
-	 * also patch the ed so it looks as if those tds completed normally.
+	/* Get rid of all later tds from this urb.  We don't have
+	 * to be careful: no errors and nothing was transferred.
+	 * Also patch the ed so it looks as if those tds completed normally.
 	 */
 	while (tmp != &ed->td_list) {
 		struct td	*next;
-		__hc32		info;
 
 		next = list_entry (tmp, struct td, td_list);
 		tmp = next->td_list.next;
@@ -819,14 +818,9 @@ ed_halted (struct ohci_hcd *ohci, struct td *td, int cc, struct td *rev)
 		 * then we need to leave the control STATUS packet queued
 		 * and clear ED_SKIP.
 		 */
-		info = next->hwINFO;
-		info |= cpu_to_hc32 (ohci, TD_DONE);
-		info &= ~cpu_to_hc32 (ohci, TD_CC);
-		next->hwINFO = info;
-
-		next->next_dl_td = rev;
-		rev = next;
 
+		list_del(&next->td_list);
+		urb_priv->td_cnt++;
 		ed->hwHeadP = next->hwNextTD | toggle;
 	}
 
@@ -852,8 +846,6 @@ ed_halted (struct ohci_hcd *ohci, struct td *td, int cc, struct td *rev)
 			hc32_to_cpu (ohci, td->hwINFO),
 			cc, cc_to_error [cc]);
 	}
-
-	return rev;
 }
 
 /* replies to the request have to be on a FIFO basis so
@@ -890,7 +882,7 @@ static struct td *dl_reverse_done_list (struct ohci_hcd *ohci)
 		 */
 		if (cc != TD_CC_NOERROR
 				&& (td->ed->hwHeadP & cpu_to_hc32 (ohci, ED_H)))
-			td_rev = ed_halted (ohci, td, cc, td_rev);
+			ed_halted(ohci, td, cc);
 
 		td->next_dl_td = td_rev;
 		td_rev = td;