On Fri, 30 May 2014, Huang Rui wrote:
> Currently, in usb_sg_wait routine there isn't a timeout on waiting for
> completion signal. When using TEST 5 -> 8 at usbtest module to verify
> a new device controller with gadget zero, it might be hang on this
> phase and this routine waits forever. And it's better to report a
> error even though it fails.
>
> So it should use a test_sg_wait instead of usb_sg_wait to add a
> timeout about 10s to export a TIMEOUT error to return in usbtest
> driver.
>
> Reference: http://marc.info/?l=linux-usb&m=140137751813423&w=2
> +/*
> + * Some codes are borrowed from usb_sg_wait and sg_clean routines
> + */
> +static void test_sg_clean(struct usb_sg_request *io)
> +{
> + if (io->urbs) {
> + while (io->entries--)
> + usb_free_urb(io->urbs[io->entries]);
> + kfree(io->urbs);
> + io->urbs = NULL;
> + }
> + io->dev = NULL;
> +}
> +
> +static int test_sg_wait(struct usb_sg_request *io, unsigned long timeout)
> +{
> + int i;
> + int entries = io->entries;
> + long timeleft;
...
Ugh, don't make a copy of the existing code. Use the facilities the
way they are meant to be used. Like the patch below.
Alan Stern
Index: usb-3.15/drivers/usb/misc/usbtest.c
===================================================================
--- usb-3.15.orig/drivers/usb/misc/usbtest.c
+++ usb-3.15/drivers/usb/misc/usbtest.c
@@ -7,7 +7,7 @@
#include <linux/moduleparam.h>
#include <linux/scatterlist.h>
#include <linux/mutex.h>
-
+#include <linux/timer.h>
#include <linux/usb.h>
#define SIMPLE_IO_TIMEOUT 10000 /* in milliseconds */
@@ -484,6 +484,13 @@ alloc_sglist(int nents, int max, int var
return sg;
}
+static void sg_timeout(unsigned long _req)
+{
+ struct usb_sg_request *req = (struct usb_sg_request *) _req;
+
+ usb_sg_cancel(req);
+}
+
static int perform_sglist(
struct usbtest_dev *tdev,
unsigned iterations,
@@ -495,6 +502,9 @@ static int perform_sglist(
{
struct usb_device *udev = testdev_to_usbdev(tdev);
int retval = 0;
+ struct timer_list sg_timer;
+
+ setup_timer_on_stack(&sg_timer, sg_timeout, (unsigned long) req);
while (retval == 0 && iterations-- > 0) {
retval = usb_sg_init(req, udev, pipe,
@@ -505,7 +515,10 @@ static int perform_sglist(
if (retval)
break;
+ mod_timer(&sg_timer, jiffies +
+ msecs_to_jiffies(SIMPLE_IO_TIMEOUT));
usb_sg_wait(req);
+ del_timer_sync(&sg_timer);
retval = req->status;
/* FIXME check resulting data pattern */
--
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