On 11/22/2018 6:51 PM, Maxime Coquelin wrote:
>
>
> On 11/22/18 7:23 PM, Ferruh Yigit wrote:
>> On 11/22/2018 5:09 PM, Maxime Coquelin wrote:
>>> The packed ring defines were declared only if kernel
>>> header does not declare them.
>>> The problem is that they are not applied in upstream kernel,
>>> and some changes in the names have been required.
>>>
>>> This patch declares the defines unconditionally, which
>>> fixes potential build issues.
>>
>> +1 to address possible build issues.
>>
>>>
>>> Fixes: 297b1e7350f6 ("vhost: add virtio packed virtqueue defines")
>>> Cc: sta...@dpdk.org
>>>
>>> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
>>> ---
>>> lib/librte_vhost/vhost.h | 22 +++++++++++-----------
>>> 1 file changed, 11 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
>>> index 760f42192..5218f1b12 100644
>>> --- a/lib/librte_vhost/vhost.h
>>> +++ b/lib/librte_vhost/vhost.h
>>> @@ -219,13 +219,6 @@ struct vhost_msg {
>>>
>>> #define VIRTIO_F_RING_PACKED 34
>>>
>>> -#define VRING_DESC_F_NEXT 1
>>> -#define VRING_DESC_F_WRITE 2
>>> -#define VRING_DESC_F_INDIRECT 4
>>
>> Why these are not re-defined below? Not used?
>
> These defines are in kernel headers since the beginning of virtio
> support, so there are no reasons to keep them (and they aren't packed-
> ring specific).
>
> I can let them if you prefer, it does not hurt but shouldn't be here.
Not required, I just want to confirm nothing missed.
>
>>> -
>>> -#define VRING_DESC_F_AVAIL (1ULL << 7)
>>> -#define VRING_DESC_F_USED (1ULL << 15)
>>> -
>>> struct vring_packed_desc {
>>> uint64_t addr;
>>> uint32_t len;
>>> @@ -233,16 +226,23 @@ struct vring_packed_desc {
>>> uint16_t flags;
>>> };
>>>
>>> -#define VRING_EVENT_F_ENABLE 0x0
>>> -#define VRING_EVENT_F_DISABLE 0x1
>>> -#define VRING_EVENT_F_DESC 0x2
>>> -
>>> struct vring_packed_desc_event {
>>> uint16_t off_wrap;
>>> uint16_t flags;
>>> };
>>> #endif
>>>
>>> +/*
>>> + * Declare below packed ring defines unconditionally
>>> + * as Kernel header might use different names.
>>> + */
>>> +#define VRING_DESC_F_AVAIL (1ULL << 7)
>>> +#define VRING_DESC_F_USED (1ULL << 15)
>>> +
>>> +#define VRING_EVENT_F_ENABLE 0x0
>>> +#define VRING_EVENT_F_DISABLE 0x1
>>> +#define VRING_EVENT_F_DESC 0x2
>>
>> What if Linux changes mind and uses old names again, build will fail again.
>> If
>> related part in Linux is not released yet, what do you think being on safe
>> side
>> and adding these defines with "#ifndef" wrap?
>
> There are the "old" ones.
> In any case it will work (I tested it).
I see they are the old ones but is there any chance that kernel uses them again
(for some odd reason) ? Which can break the build. Should we add a protection?
>
> In a future release, I plan to get rid of this dependency with Kernel
> which only causes problems.
>
> There was a benefit at the beginning when all needed declarations where
> in the Kernel headers. But now, every time we add a new virtio feature,
> we have to check kernel supports it and if not define it.
>
> Thanks,
> Maxime
>>> +
>>> /*
>>> * Available and used descs are in same order
>>> */
>>>
>>
