xHCI: cancel command after command timeout

The patch is used to cancel command when the command isn't
acknowledged and a timeout occurs.

This patch should be backported to kernels as old as 3.0, that contain
the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an
assertion to check for virt_dev=0 bug." That commit papers over a NULL
pointer dereference, and this patch fixes the underlying issue that
caused the NULL pointer dereference.

Signed-off-by: Elric Fu <elricfu1@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 5c1425d..42cff8b 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -2402,6 +2402,7 @@
 	struct completion *cmd_completion;
 	u32 *cmd_status;
 	struct xhci_virt_device *virt_dev;
+	union xhci_trb *cmd_trb;
 
 	spin_lock_irqsave(&xhci->lock, flags);
 	virt_dev = xhci->devs[udev->slot_id];
@@ -2447,6 +2448,7 @@
 	}
 	init_completion(cmd_completion);
 
+	cmd_trb = xhci->cmd_ring->dequeue;
 	if (!ctx_change)
 		ret = xhci_queue_configure_endpoint(xhci, in_ctx->dma,
 				udev->slot_id, must_succeed);
@@ -2468,14 +2470,17 @@
 	/* Wait for the configure endpoint command to complete */
 	timeleft = wait_for_completion_interruptible_timeout(
 			cmd_completion,
-			USB_CTRL_SET_TIMEOUT);
+			XHCI_CMD_DEFAULT_TIMEOUT);
 	if (timeleft <= 0) {
 		xhci_warn(xhci, "%s while waiting for %s command\n",
 				timeleft == 0 ? "Timeout" : "Signal",
 				ctx_change == 0 ?
 					"configure endpoint" :
 					"evaluate context");
-		/* FIXME cancel the configure endpoint command */
+		/* cancel the configure endpoint command */
+		ret = xhci_cancel_cmd(xhci, command, cmd_trb);
+		if (ret < 0)
+			return ret;
 		return -ETIME;
 	}
 
@@ -3424,8 +3429,10 @@
 	unsigned long flags;
 	int timeleft;
 	int ret;
+	union xhci_trb *cmd_trb;
 
 	spin_lock_irqsave(&xhci->lock, flags);
+	cmd_trb = xhci->cmd_ring->dequeue;
 	ret = xhci_queue_slot_control(xhci, TRB_ENABLE_SLOT, 0);
 	if (ret) {
 		spin_unlock_irqrestore(&xhci->lock, flags);
@@ -3437,12 +3444,12 @@
 
 	/* XXX: how much time for xHC slot assignment? */
 	timeleft = wait_for_completion_interruptible_timeout(&xhci->addr_dev,
-			USB_CTRL_SET_TIMEOUT);
+			XHCI_CMD_DEFAULT_TIMEOUT);
 	if (timeleft <= 0) {
 		xhci_warn(xhci, "%s while waiting for a slot\n",
 				timeleft == 0 ? "Timeout" : "Signal");
-		/* FIXME cancel the enable slot request */
-		return 0;
+		/* cancel the enable slot request */
+		return xhci_cancel_cmd(xhci, NULL, cmd_trb);
 	}
 
 	if (!xhci->slot_id) {
@@ -3503,6 +3510,7 @@
 	struct xhci_slot_ctx *slot_ctx;
 	struct xhci_input_control_ctx *ctrl_ctx;
 	u64 temp_64;
+	union xhci_trb *cmd_trb;
 
 	if (!udev->slot_id) {
 		xhci_dbg(xhci, "Bad Slot ID %d\n", udev->slot_id);
@@ -3541,6 +3549,7 @@
 	xhci_dbg_ctx(xhci, virt_dev->in_ctx, 2);
 
 	spin_lock_irqsave(&xhci->lock, flags);
+	cmd_trb = xhci->cmd_ring->dequeue;
 	ret = xhci_queue_address_device(xhci, virt_dev->in_ctx->dma,
 					udev->slot_id);
 	if (ret) {
@@ -3553,7 +3562,7 @@
 
 	/* ctrl tx can take up to 5 sec; XXX: need more time for xHC? */
 	timeleft = wait_for_completion_interruptible_timeout(&xhci->addr_dev,
-			USB_CTRL_SET_TIMEOUT);
+			XHCI_CMD_DEFAULT_TIMEOUT);
 	/* FIXME: From section 4.3.4: "Software shall be responsible for timing
 	 * the SetAddress() "recovery interval" required by USB and aborting the
 	 * command on a timeout.
@@ -3561,7 +3570,10 @@
 	if (timeleft <= 0) {
 		xhci_warn(xhci, "%s while waiting for address device command\n",
 				timeleft == 0 ? "Timeout" : "Signal");
-		/* FIXME cancel the address device command */
+		/* cancel the address device command */
+		ret = xhci_cancel_cmd(xhci, NULL, cmd_trb);
+		if (ret < 0)
+			return ret;
 		return -ETIME;
 	}
 
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index f075411..357815d 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1256,6 +1256,9 @@
 	union xhci_trb		*last_trb;
 };
 
+/* xHCI command default timeout value */
+#define XHCI_CMD_DEFAULT_TIMEOUT	(5 * HZ)
+
 /* command descriptor */
 struct xhci_cd {
 	struct list_head	cancel_cmd_list;