Re: [dpdk-dev] [PATCH v9 3/8] net/virtio: add packed virtqueue helpers

[Jens Freimann <jfreimann@redhat.com>]

On Thu, Oct 25, 2018 at 05:23:53PM +0800, Tiwei Bie wrote:
>On Wed, Oct 24, 2018 at 04:32:31PM +0200, Jens Freimann wrote:
>> Add helper functions to set/clear and check descriptor flags.
>>
>> Signed-off-by: Jens Freimann <jfreimann@redhat.com>
>> ---
>>  drivers/net/virtio/virtio_ring.h | 26 ++++++++++++++++++++++++++
>>  1 file changed, 26 insertions(+)
>>
>> diff --git a/drivers/net/virtio/virtio_ring.h b/drivers/net/virtio/virtio_ring.h
>> index f84ab5e34..629d3477a 100644
>> --- a/drivers/net/virtio/virtio_ring.h
>> +++ b/drivers/net/virtio/virtio_ring.h
>> @@ -77,6 +77,8 @@ struct vring_packed_desc_event {
>>
>>  struct vring {
>>  	unsigned int num;
>> +	unsigned int avail_wrap_counter;
>> +	unsigned int used_wrap_counter;
>
>Above fields should be defined in struct virtqueue.

ok

regards,
Jens 
>
>>  	union {
>>  		struct vring_desc_packed *desc_packed;
>>  		struct vring_desc *desc;
>> @@ -91,6 +93,30 @@ struct vring {
>>  	};
>>  };
>>
>> +static inline void
>> +_set_desc_avail(struct vring_desc_packed *desc, int wrap_counter)
>> +{
>> +	desc->flags |= VRING_DESC_F_AVAIL(wrap_counter) |
>> +		       VRING_DESC_F_USED(!wrap_counter);
>> +}
>> +
>> +static inline void
>> +set_desc_avail(struct vring *vr, struct vring_desc_packed *desc)
>> +{
>> +	_set_desc_avail(desc, vr->avail_wrap_counter);
>> +}
>> +
>> +static inline int
>> +desc_is_used(struct vring_desc_packed *desc, struct vring *vr)
>> +{
>> +	uint16_t used, flags;
>> +
>> +	flags = desc->flags;
>> +	used = !!(flags & VRING_DESC_F_USED(1));
>> +
>> +	return used == vr->used_wrap_counter;
>> +}
>> +
>>  /* The standard layout for the ring is a continuous chunk of memory which
>>   * looks like this.  We assume num is a power of 2.
>>   *
>> --
>> 2.17.1
>>