usb: cdc-acm: handle unlinked urb in acm read callback

commit 1945446 upstream. In current acm driver, the bulk-in callback function ignores the URBs unlinked in usb core. This causes unexpected data loss in some cases. For example, runtime suspend entry will unlinked all urbs and set urb->status to -ENOENT even those urbs might have data not processed yet. Hence, data loss occurs. This patch lets bulk-in callback function handle unlinked urbs to avoid data loss. Signed-off-by: Tang Jian Qiang <[email protected]> Signed-off-by: Lu Baolu <[email protected]> Acked-by: Oliver Neukum <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
openbmc · Feb 19, 2016 · 8b49e8a · 8b49e8a
1 parent d81ebb7
commit 8b49e8a
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
@@ -428,7 +428,8 @@ static void acm_read_bulk_callback(struct urb *urb)
 		set_bit(rb->index, &acm->read_urbs_free);
 		dev_dbg(&acm->data->dev, "%s - non-zero urb status: %d\n",
 							__func__, status);
-		return;
+		if ((status != -ENOENT) || (urb->actual_length == 0))
+			return;
 	}
 
 	usb_mark_last_busy(acm->dev);