[SLOF] [PATCH v1 24/27] virtio-net: make net_hdr_size a variable

[Alexey Kardashevskiy]

On 01/13/2016 10:17 PM, Nikunj A Dadhania wrote:
> Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
> ---
>   lib/libvirtio/virtio-net.c | 15 +++++++++------
>   1 file changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/lib/libvirtio/virtio-net.c b/lib/libvirtio/virtio-net.c
> index 18ad2f7..9c51a39 100644
> --- a/lib/libvirtio/virtio-net.c
> +++ b/lib/libvirtio/virtio-net.c
> @@ -53,6 +53,8 @@ struct virtio_net_hdr {
>   	// uint16_t  num_buffers;	/* Only if VIRTIO_NET_F_MRG_RXBUF */
>   };
>
> +static unsigned int net_hdr_size;


Why? Just because sizeof(struct virtio_net_hdr) is longer? If so, then add 
"const".



> +
>   static uint16_t last_rx_idx;	/* Last index in RX "used" ring */
>
>   /**
> @@ -128,8 +130,9 @@ static int virtionet_init(net_driver_t *driver)
>   	/* Device specific setup - we do not support special features right now */
>   	virtio_set_guest_features(&virtiodev,  0);
>
> +	net_hdr_size = sizeof(struct virtio_net_hdr);
>   	/* Allocate memory for one transmit an multiple receive buffers */
> -	vq_rx.buf_mem = SLOF_alloc_mem((BUFFER_ENTRY_SIZE+sizeof(struct virtio_net_hdr))
> +	vq_rx.buf_mem = SLOF_alloc_mem((BUFFER_ENTRY_SIZE+net_hdr_size)
>   				   * RX_QUEUE_SIZE);

Nit: I'd suggest wrapping after "+" and have both operands of "*" on the 
same line.



>   	if (!vq_rx.buf_mem) {
>   		printf("virtionet: Failed to allocate buffers!\n");
> @@ -140,14 +143,14 @@ static int virtionet_init(net_driver_t *driver)
>   	/* Prepare receive buffer queue */
>   	for (i = 0; i < RX_QUEUE_SIZE; i++) {
>   		uint64_t addr = (uint64_t)vq_rx.buf_mem
> -			+ i * (BUFFER_ENTRY_SIZE+sizeof(struct virtio_net_hdr));
> +			+ i * (BUFFER_ENTRY_SIZE+net_hdr_size);
>   		uint32_t id = i*2;
>   		/* Descriptor for net_hdr: */
> -		fill_desc(&vq_rx.desc[id], 0, addr, sizeof(struct virtio_net_hdr),
> +		fill_desc(&vq_rx.desc[id], 0, addr, net_hdr_size,
>   			  VRING_DESC_F_NEXT | VRING_DESC_F_WRITE, id + 1);
>
>   		/* Descriptor for data: */
> -		fill_desc(&vq_rx.desc[id+1], 0, addr + sizeof(struct virtio_net_hdr),
> +		fill_desc(&vq_rx.desc[id+1], 0, addr + net_hdr_size,
>   			  BUFFER_ENTRY_SIZE, VRING_DESC_F_WRITE, 0);
>
>   		vq_rx.avail->ring[i] = id;
> @@ -221,7 +224,7 @@ static int virtionet_xmit(char *buf, int len)
>
>   	/* Set up virtqueue descriptor for header */
>   	fill_desc(&vq_tx.desc[id], 0, (uint64_t)&nethdr,
> -		  sizeof(struct virtio_net_hdr), VRING_DESC_F_NEXT, id + 1);
> +		  net_hdr_size, VRING_DESC_F_NEXT, id + 1);
>
>   	/* Set up virtqueue descriptor for data */
>   	fill_desc(&vq_tx.desc[id+1], 0, (uint64_t)buf, len, 0, 0);
> @@ -254,7 +257,7 @@ static int virtionet_receive(char *buf, int maxlen)
>   	id = (vq_rx.used->ring[last_rx_idx % vq_rx.size].id + 1)
>   	     % vq_rx.size;
>   	len = vq_rx.used->ring[last_rx_idx % vq_rx.size].len
> -	      - sizeof(struct virtio_net_hdr);
> +	      - net_hdr_size;
>
>   	dprintf("virtionet_receive() last_rx_idx=%i, vq_rx.used->idx=%i,"
>   		" id=%i len=%i\n", last_rx_idx, vq_rx.used->idx, id, len);
>


-- 
Alexey