[Spice-devel] UsbDk-related patches

[Chris Dickens]

Hi,

I have addressed this issue with commit c8f71151.

Regards,
Chris

On Wed, Jan 27, 2016 at 6:06 AM, Dmitry Fleytman <dmitry at daynix.com> wrote:
>
>
> Sent from my iPhone
>
>> On 27 Jan 2016, at 15:58, Christophe Fergeau <cfergeau at redhat.com> wrote:
>>
>>> On Wed, Jan 27, 2016 at 02:09:25PM +0200, Dmitry Fleytman wrote:
>>>
>>>> On 27 Jan 2016, at 14:00 PM, Christophe Fergeau <cfergeau at redhat.com> wrote:
>>>>
>>>> On Wed, Jan 27, 2016 at 01:51:12PM +0200, Dmitry Fleytman wrote:
>>>>> Hello, Spice List
>>>>>
>>>>> I just got a confirmation that UsbDk backend integration for libusb was pushed upstream:
>>>>>
>>>>> 24c5289 build: Integrate usbdk backend
>>>>> 8823c17 usbdk: Introduce usbdk backend
>>>>> 5d83aba windows: Rename windows_usb.h/c windows_winusb.h/c
>>>>> 92a3278 windows: Move common definitions to a separate file
>>>>>
>>>>> (see at https://github.com/libusb/libusb/commits/master)
>>>>
>>>> Didn't
>>>> https://github.com/libusb/libusb/commit/cdfe236931ef3fd06adac0fdf6df49baa39ff35e
>>>> reintroduce the bug where if there are usbdk issues,
>>>> libusb_init() will fail the first time it's called, and then report
>>>> success without doing any initialisation?
>>>
>>> (looping Chris)
>>>
>>> Hi Chris,
>>>
>>> There is an opinion that commit
>>> (https://github.com/libusb/libusb/commit/cdfe236931ef3fd06adac0fdf6df49baa39ff35e)
>>> is problematic (see above). If so, there is the symmetrical problem
>>> with WinUsb backend as well. What do you think?
>>
>> The WinUsb backend is doing things slightly differently, and looks more
>> correct, something like:
>> (not sure how bad it is to call window_common_exit() when windows_common_init()
>> hasn't been called, this can happen with this patch if load_usbdk_helper_dll fails)
>
> Here, it is ok to call cleanup when init fails. The idea is to avoid duplication of cleanup code.
>
>>
>> diff --git a/libusb/os/windows_usbdk.c b/libusb/os/windows_usbdk.c
>> index 9abb83e..2b97f69 100644
>> --- a/libusb/os/windows_usbdk.c
>> +++ b/libusb/os/windows_usbdk.c
>> @@ -195,25 +195,30 @@ error_unload:
>>
>> static int usbdk_init(struct libusb_context *ctx)
>> {
>> -       int r;
>> +       int r = LIBUSB_ERROR_OTHER;
>>
>>        if (++concurrent_usage == 0) {
>>                r = load_usbdk_helper_dll(ctx);
>>                if (r)
>> -                       return r;
>> +                       goto init_exit;
>>
>>                init_polling();
>>
>>                r = windows_common_init(ctx);
>>                if (r)
>> -                       goto error_roll_back;
>> +                       goto init_exit;
>>        }
>>
>> -       return LIBUSB_SUCCESS;
>> +       r = LIBUSB_SUCCESS;
>> +
>> +init_exit:
>> +       if (!concurrent_usage && r != LIBUSB_SUCCESS) { // First init failed?
>> +               windows_common_exit();
>> +               unload_usbdk_helper_dll();
>> +
>> +       if (r != LIBUSB_SUCCESS)
>> +               --concurrent_usage;
>>
>> -error_roll_back:
>> -       windows_common_exit();
>> -       unload_usbdk_helper_dll();
>>        return r;
>> }
>>
>> Christophe