[dpdk-dev] [PATCH v5 02/15] vhost: add helpers for packed virtqueues

[Maxime Coquelin]

On 06/29/2018 05:51 PM, Tiwei Bie wrote:
> On Fri, Jun 22, 2018 at 03:43:14PM +0200, Maxime Coquelin wrote:
>> From: Jens Freimann <jfreimann at redhat.com>
>>
>> Add some helper functions to check descriptor flags
>> and check if a vring is of type packed.
>>
>> Signed-off-by: Jens Freimann <jfreimann at redhat.com>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>> ---
>>   lib/librte_vhost/vhost.h         |  6 ++++++
>>   lib/librte_vhost/virtio-packed.h | 16 ++++++++++++++++
>>   2 files changed, 22 insertions(+)
>>
>> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
>> index bf2059198..34a614c97 100644
>> --- a/lib/librte_vhost/vhost.h
>> +++ b/lib/librte_vhost/vhost.h
>> @@ -319,6 +319,12 @@ struct virtio_net {
>>   	struct vhost_user_extern_ops extern_ops;
>>   } __rte_cache_aligned;
>>   
>> +static __rte_always_inline bool
>> +vq_is_packed(struct virtio_net *dev)
>> +{
>> +	return dev->features & (1ull << VIRTIO_F_RING_PACKED);
>> +}
>> +
>>   #define VHOST_LOG_PAGE	4096
>>   
>>   /*
>> diff --git a/lib/librte_vhost/virtio-packed.h b/lib/librte_vhost/virtio-packed.h
>> index 744b3991b..21fe5045b 100644
>> --- a/lib/librte_vhost/virtio-packed.h
>> +++ b/lib/librte_vhost/virtio-packed.h
>> @@ -19,4 +19,20 @@ struct vring_desc_packed {
>>   	uint16_t flags;
>>   };
>>   
>> +
>> +static inline int
> 
> Better to return bool.

Yes.

>> +desc_is_avail(struct vring_desc_packed *desc, uint16_t wrap_counter)
>> +{
>> +	if (wrap_counter == 1) {
>> +		if ((desc->flags & VRING_DESC_F_AVAIL) &&
>> +				!(desc->flags & VRING_DESC_F_USED))
>> +			return 1;
>> +	} else {
>> +		if (!(desc->flags & VRING_DESC_F_AVAIL) &&
>> +				(desc->flags & VRING_DESC_F_USED))
>> +			return 1;
>> +	}
>> +	return 0;
> 
> Maybe something like:
> 
> return wrap_counter == !!(desc->flags & VRING_DESC_F_AVAIL) &&
> 	wrap_counter != !!(dsec->flags & VRING_DESC_F_USED);
> 
> is better?

Definitely!

Thanks,
Maxime

> Best regards,
> Tiwei Bie
> 
>> +}
>> +
>>   #endif /* __VIRTIO_PACKED_H */
>> -- 
>> 2.14.4
>>