Re: [PATCHv4 2/2] vhost_net: a kernel-level virtio server

On Thu, 27 Aug 2009 07:40:26 pm Michael S. Tsirkin wrote:

On Wed, Aug 26, 2009 at 03:40:59PM +0200, Arnd Bergmann wrote:

quoted

On Tuesday 25 August 2009, Michael S. Tsirkin wrote:

quoted

quoted

 I'd like to avoid that here,
though it's kind of ugly.  We'd need VHOST_GET_FEATURES (and ACK) to take a
struct like:

      u32 feature_size;
      u32 features[];

Hmm, variable length ioctl arguments, I'd rather not go there.
The ioctl infrastructure already has a length argument encoded
in the ioctl number. We can use that if we need more, e.g.

/* now */
#define VHOST_GET_FEATURES     _IOR(VHOST_VIRTIO, 0x00, __u64)
/*
 * uncomment if we run out of feature bits:

struct vhost_get_features2 {
	__u64 bits[2];
};
#define VHOST_GET_FEATURES2     _IOR(VHOST_VIRTIO, 0x00, \
			struct  vhost_get_features2)
 */

I thought so, too. Rusty, agree?

Yep, am convinced.  Make it u64 to stop us having to do this tomorrow, then
we can always extend later.

Thanks,
Rusty.