From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>,
dev@dpdk.org, thomas@monjalon.net, tiwei.bie@intel.com,
zhihong.wang@intel.com, jfreiman@redhat.com
Cc: stable@dpdk.org
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] vhost: fix packed ring defines declaration
Date: Thu, 22 Nov 2018 19:20:00 +0000 [thread overview]
Message-ID: <590b480d-e2db-b299-82da-bc96a556a5e9@intel.com> (raw)
In-Reply-To: <5437708e-d8cf-fe17-6fd6-fad67b3a0eb7@redhat.com>
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: stable@dpdk.org
>>>
>>> Signed-off-by: Maxime Coquelin <maxime.coquelin@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
>>> */
>>>
>>
next prev parent reply other threads:[~2018-11-22 19:20 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-22 17:09 [dpdk-stable] " Maxime Coquelin
2018-11-22 18:23 ` [dpdk-stable] [dpdk-dev] " Ferruh Yigit
2018-11-22 18:51 ` Maxime Coquelin
2018-11-22 19:20 ` Ferruh Yigit [this message]
2018-11-22 19:50 ` Maxime Coquelin
2018-11-22 22:04 ` Ferruh Yigit
2018-11-22 22:14 ` Ferruh Yigit
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