Re: [PATCH 3/6] virtio: allow extra context per descriptor

From	Cornelia Huck <cornelia.huck@de.ibm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/6] virtio: allow extra context per descriptor
Date	2017-03-30 09:30 +0200
Message-ID	<tqCGR-2MS-13@gated-at.bofh.it> (permalink)
References	<tqsRb-3S4-7@gated-at.bofh.it> <tqsRb-3S4-9@gated-at.bofh.it>
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On Wed, 29 Mar 2017 23:48:53 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> Allow extra context per descriptor. To avoid slow down for data path,
> this disables use of indirect descriptors for this vq.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  drivers/virtio/virtio_ring.c | 70 ++++++++++++++++++++++++++++++++++++--------
>  include/linux/virtio.h       |  9 ++++++
>  2 files changed, 66 insertions(+), 13 deletions(-)
> 

>  /**
> + * virtqueue_add_inbuf_ctx - expose input buffers to other end
> + * @vq: the struct virtqueue we're talking about.
> + * @sg: scatterlist (must be well-formed and terminated!)
> + * @num: the number of entries in @sg writable by other side
> + * @data: the token identifying the buffer.
> + * @ctx: extra context for the token

I think that needs do that ctx != NULL collides with indirect
descriptors.

> + * @gfp: how to do memory allocations (if necessary).
> + *
> + * Caller must ensure we don't call this with other virtqueue operations
> + * at the same time (except where noted).
> + *
> + * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
> + */
> +int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
> +			struct scatterlist *sg, unsigned int num,
> +			void *data,
> +			void *ctx,
> +			gfp_t gfp)
> +{
> +	return virtqueue_add(vq, &sg, num, 0, 1, data, ctx, gfp);
> +}
> +EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);

Thread

[PATCH 0/6] virtio: support extra per-buffer context "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-29 23:00 +0200
  [PATCH 3/6] virtio: allow extra context per descriptor "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-29 23:00 +0200
    Re: [PATCH 3/6] virtio: allow extra context per descriptor Cornelia Huck <cornelia.huck@de.ibm.com> - 2017-03-30 09:30 +0200
      Re: [PATCH 3/6] virtio: allow extra context per descriptor "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-30 16:40 +0200
  [PATCH 2/6] virtio: add context flag to find vqs "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-29 23:00 +0200
    Re: [PATCH 2/6] virtio: add context flag to find vqs Cornelia Huck <cornelia.huck@de.ibm.com> - 2017-03-30 09:20 +0200
      Re: [PATCH 2/6] virtio: add context flag to find vqs "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-30 17:00 +0200
  [PATCH 1/6] virtio: wrap find_vqs "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-29 23:00 +0200
    RE: [PATCH 1/6] virtio: wrap find_vqs "Gonglei (Arei)" <arei.gonglei@huawei.com> - 2017-03-30 03:00 +0200
    Re: [PATCH 1/6] virtio: wrap find_vqs Jason Wang <jasowang@redhat.com> - 2017-03-30 08:10 +0200
      Re: [PATCH 1/6] virtio: wrap find_vqs "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-30 16:40 +0200
        Re: [PATCH 1/6] virtio: wrap find_vqs Jason Wang <jasowang@redhat.com> - 2017-03-31 06:10 +0200
          Re: [PATCH 1/6] virtio: wrap find_vqs "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-31 18:30 +0200
    Re: [PATCH 1/6] virtio: wrap find_vqs Cornelia Huck <cornelia.huck@de.ibm.com> - 2017-03-30 09:20 +0200
    Re: [PATCH 1/6] virtio: wrap find_vqs Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-04-01 18:20 +0200
  [PATCH 5/6] virtio_net: rework mergeable buffer handling "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-29 23:00 +0200
  [PATCH 4/6] virtio_net: allow specifying context for rx "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-29 23:00 +0200
    Re: [PATCH 4/6] virtio_net: allow specifying context for rx Cornelia Huck <cornelia.huck@de.ibm.com> - 2017-03-30 09:30 +0200
      Re: [PATCH 4/6] virtio_net: allow specifying context for rx "Michael S. Tsirkin" <mst@redhat.com> - 2017-03-30 16:40 +0200
        Re: [PATCH 4/6] virtio_net: allow specifying context for rx Cornelia Huck <cornelia.huck@de.ibm.com> - 2017-03-30 16:50 +0200

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