Re: [Xen-devel][PATCH]: Fix some bugs in usbfront

["Ky Srinivasan" <ksrinivasan@xxxxxxxxxx>]

>>> On 3/12/2010 at  5:42 PM, in message <20100312224201.GN1878@xxxxxxxxxxx>, 
>>> Pasi
KÃrkkÃinen<pasik@xxxxxx> wrote: 
> On Fri, Mar 12, 2010 at 03:34:00PM -0700, Ky Srinivasan wrote:
>> 
>> 
>> >>> On 3/12/2010 at  5:30 PM, in message 
>> >>> <20100312223035.GM1878@xxxxxxxxxxx>, 
> Pasi
>> KÃrkkÃinen<pasik@xxxxxx> wrote: 
>> > On Fri, Mar 12, 2010 at 11:25:21AM -0700, Ky Srinivasan wrote:
>> >> The attached patch fixes some  bugs in usbfront.
>> >> 
>> > 
>> > What kernel version is this patch against? linux-2.6.18-xen? 
>> 
>> Once again this  patch is against 2.6.32 kernel (sles11 sp1). 
>> Sorry for not making this clear in the patch.
> 
> Ok. 
> 
> Does the SLES11 2.6.27 kernel-xen have usbback/usbfront? 
> How about the opensuse kernel-xen versions? 
Well, PV USB will be supported in sles11 sp1. I am not sure what the plans are 
for other versions.
> 
> I can add the info to:
> http://wiki.xensource.com/xenwiki/XenUSBPassthrough
That will be good. 

Thanks,

K. Y
> 
> -- Pasi
> 
>> 
>> Regards,
>> K. Y
>> > -- Pasi
>> > 
>> >> Signed-off-by: K. Y. Srinivasan <ksrinivasan@xxxxxxxxxx>
>> >> 
>> >> 
>> >> 
>> >> 
>> > 
>> >> Bug#584218: Fix a  scheduling race in usbfront. Create the thread only 
> after 
>> > we 
>> >> are connected. The current code schedules the thread at a point where the 
>> >> communication rings are not initialized yet.
>> >> 
>> >> Signed-off-by: K. Y. Srinivasan <ksrinivasan@xxxxxxxxxx>
>> >> 
>> >> Index: linux/drivers/xen/usbfront/xenbus.c
>> >> ===================================================================
>> >> --- linux.orig/drivers/xen/usbfront/xenbus.c      2010-03-10 
>> >> 12:10:58.000000000 -0700
>> >> +++ linux/drivers/xen/usbfront/xenbus.c   2010-03-10 12:17:24.000000000 
>> >> -0700
>> >> @@ -192,11 +192,23 @@ static int connect(struct xenbus_device
>> >>   usbif_conn_request_t *req;
>> >>   int i, idx, err;
>> >>   int notify;
>> >> + char name[TASK_COMM_LEN];
>> >> + struct usb_hcd *hcd;
>> >> +
>> >> + hcd = info_to_hcd(info);
>> >> + snprintf(name, TASK_COMM_LEN, "xenhcd.%d", hcd->self.busnum);
>> >>  
>> >>   err = talk_to_backend(dev, info);
>> >>   if (err)
>> >>           return err;
>> >>  
>> >> + info->kthread = kthread_run(xenhcd_schedule, info, name);
>> >> + if (IS_ERR(info->kthread)) {
>> >> +         err = PTR_ERR(info->kthread);
>> >> +         info->kthread = NULL;
>> >> +         xenbus_dev_fatal(dev, err, "Error creating thread");
>> >> +         return err;
>> >> + }
>> >>   /* prepare ring for hotplug notification */
>> >>   for (idx = 0, i = 0; i < USB_CONN_RING_SIZE; i++) {
>> >>           req = RING_GET_REQUEST(&info->conn_ring, idx);
>> >> @@ -274,7 +286,6 @@ static int usbfront_probe(struct xenbus_
>> >>   int err;
>> >>   struct usb_hcd *hcd;
>> >>   struct usbfront_info *info;
>> >> - char name[TASK_COMM_LEN];
>> >>  
>> >>   if (usb_disabled())
>> >>           return -ENODEV;
>> >> @@ -298,13 +309,6 @@ static int usbfront_probe(struct xenbus_
>> >>   }
>> >>  
>> >>   init_waitqueue_head(&info->wq);
>> >> - snprintf(name, TASK_COMM_LEN, "xenhcd.%d", hcd->self.busnum);
>> >> - info->kthread = kthread_run(xenhcd_schedule, info, name);
>> >> - if (IS_ERR(info->kthread)) {
>> >> -         err = PTR_ERR(info->kthread);
>> >> -         info->kthread = NULL;
>> >> -         goto fail;
>> >> - }
>> >>  
>> >>   return 0;
>> >>  
>> >> @@ -343,8 +347,8 @@ static void backend_changed(struct xenbu
>> >>   case XenbusStateInitWait:
>> >>           if (dev->state != XenbusStateInitialising)
>> >>                   break;
>> >> -         connect(dev);
>> >> -         xenbus_switch_state(dev, XenbusStateConnected);
>> >> +         if (!connect(dev))
>> >> +                 xenbus_switch_state(dev, XenbusStateConnected);
>> >>           break;
>> >>  
>> >>   case XenbusStateClosing:
>> > 
>> >> _______________________________________________
>> >> Xen-devel mailing list
>> >> Xen-devel@xxxxxxxxxxxxxxxxxxx
>> >> http://lists.xensource.com/xen-devel
>> 


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