[PATCH] usbtest: report errors in iso tests

This patch (as693b) makes the usbtest driver report errors in the
isochronous bulk transfer tests instead of always returning 0.  As an
arbitrary cutoff, an error is returned if more than 10% of the packet
transfers fail.  It also stops a test immediately upon receiving an URB
submission error.

For a test harness, it's especially important to report when errors occur!
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/misc/usbtest.c

@@ -1337,7 +1337,9 @@ struct iso_context {
 	unsigned		pending;
 	spinlock_t		lock;
 	struct completion	done;
+	int			submit_error;
 	unsigned long		errors;
+	unsigned long		packet_count;
 	struct usbtest_dev	*dev;
 };
 
@@ -1348,10 +1350,14 @@ static void iso_callback (struct urb *urb, struct pt_regs *regs)
 	spin_lock(&ctx->lock);
 	ctx->count--;
 
+	ctx->packet_count += urb->number_of_packets;
 	if (urb->error_count > 0)
 		ctx->errors += urb->error_count;
+	else if (urb->status != 0)
+		ctx->errors += urb->number_of_packets;
 
-	if (urb->status == 0 && ctx->count > (ctx->pending - 1)) {
+	if (urb->status == 0 && ctx->count > (ctx->pending - 1)
+			&& !ctx->submit_error) {
 		int status = usb_submit_urb (urb, GFP_ATOMIC);
 		switch (status) {
 		case 0:
@@ -1362,6 +1368,8 @@ static void iso_callback (struct urb *urb, struct pt_regs *regs)
 					status);
 			/* FALLTHROUGH */
 		case -ENODEV:			/* disconnected */
+		case -ESHUTDOWN:		/* endpoint disabled */
+			ctx->submit_error = 1;
 			break;
 		}
 	}
@@ -1371,8 +1379,8 @@ static void iso_callback (struct urb *urb, struct pt_regs *regs)
 	if (ctx->pending == 0) {
 		if (ctx->errors)
 			dev_dbg (&ctx->dev->intf->dev,
-				"iso test, %lu errors\n",
-				ctx->errors);
+				"iso test, %lu errors out of %lu\n",
+				ctx->errors, ctx->packet_count);
 		complete (&ctx->done);
 	}
 done:
@@ -1433,15 +1441,14 @@ test_iso_queue (struct usbtest_dev *dev, struct usbtest_param *param,
 	struct usb_device	*udev;
 	unsigned		i;
 	unsigned long		packets = 0;
-	int			status;
+	int			status = 0;
 	struct urb		*urbs[10];	/* FIXME no limit */
 
 	if (param->sglen > 10)
 		return -EDOM;
 
+	memset(&context, 0, sizeof context);
 	context.count = param->iterations * param->sglen;
-	context.pending = param->sglen;
-	context.errors = 0;
 	context.dev = dev;
 	init_completion (&context.done);
 	spin_lock_init (&context.lock);
@@ -1473,6 +1480,7 @@ test_iso_queue (struct usbtest_dev *dev, struct usbtest_param *param,
 
 	spin_lock_irq (&context.lock);
 	for (i = 0; i < param->sglen; i++) {
+		++context.pending;
 		status = usb_submit_urb (urbs [i], SLAB_ATOMIC);
 		if (status < 0) {
 			ERROR (dev, "submit iso[%d], error %d\n", i, status);
@@ -1483,12 +1491,26 @@ test_iso_queue (struct usbtest_dev *dev, struct usbtest_param *param,
 
 			simple_free_urb (urbs [i]);
 			context.pending--;
+			context.submit_error = 1;
+			break;
 		}
 	}
 	spin_unlock_irq (&context.lock);
 
 	wait_for_completion (&context.done);
-	return 0;
+
+	/*
+	 * Isochronous transfers are expected to fail sometimes.  As an
+	 * arbitrary limit, we will report an error if any submissions
+	 * fail or if the transfer failure rate is > 10%.
+	 */
+	if (status != 0)
+		;
+	else if (context.submit_error)
+		status = -EACCES;
+	else if (context.errors > context.packet_count / 10)
+		status = -EIO;
+	return status;
 
 fail:
 	for (i = 0; i < param->sglen; i++) {