On Sun, Nov 06, 2022 at 07:36:02PM +0000, Arseniy Krasnov wrote:
> To support zerocopy receive, packet's buffer allocation is changed: for
> buffers which could be mapped to user's vma we can't use 'kmalloc()'(as
> kernel restricts to map slab pages to user's vma) and raw buddy
> allocator now called. But, for tx packets(such packets won't be mapped
> to user), previous 'kmalloc()' way is used, but with special flag in
> packet's structure which allows to distinguish between 'kmalloc()' and
> raw pages buffers.
>
> Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
Hey Arseniy, great work here!
> ---
> drivers/vhost/vsock.c | 1 +
> include/linux/virtio_vsock.h | 1 +
> net/vmw_vsock/virtio_transport.c | 8 ++++++--
> net/vmw_vsock/virtio_transport_common.c | 10 +++++++++-
> 4 files changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index 5703775af129..65475d128a1d 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -399,6 +399,7 @@ vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
> return NULL;
> }
>
> + pkt->slab_buf = true;
> pkt->buf_len = pkt->len;
>
> nbytes = copy_from_iter(pkt->buf, pkt->len, &iov_iter);
> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> index 35d7eedb5e8e..d02cb7aa922f 100644
> --- a/include/linux/virtio_vsock.h
> +++ b/include/linux/virtio_vsock.h
> @@ -50,6 +50,7 @@ struct virtio_vsock_pkt {
> u32 off;
> bool reply;
> bool tap_delivered;
> + bool slab_buf;
> };
WRT the sk_buff series, I bet this bool will not be needed after the
rebase.
>
> struct virtio_vsock_pkt_info {
> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> index ad64f403536a..19909c1e9ba3 100644
> --- a/net/vmw_vsock/virtio_transport.c
> +++ b/net/vmw_vsock/virtio_transport.c
> @@ -255,16 +255,20 @@ static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
> vq = vsock->vqs[VSOCK_VQ_RX];
>
> do {
> + struct page *buf_page;
> +
> pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
> if (!pkt)
> break;
>
> - pkt->buf = kmalloc(buf_len, GFP_KERNEL);
> - if (!pkt->buf) {
> + buf_page = alloc_page(GFP_KERNEL);
> +
> + if (!buf_page) {
I think it should not be too hard to use build_skb() around the page
here after rebasing onto the sk_buff series.
> virtio_transport_free_pkt(pkt);
> break;
> }
>
> + pkt->buf = page_to_virt(buf_page);
> pkt->buf_len = buf_len;
> pkt->len = buf_len;
>
> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index a9980e9b9304..37e8dbfe2f5d 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -69,6 +69,7 @@ virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
> if (!pkt->buf)
> goto out_pkt;
>
> + pkt->slab_buf = true;
> pkt->buf_len = len;
>
> err = memcpy_from_msg(pkt->buf, info->msg, len);
> @@ -1339,7 +1340,14 @@ EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
>
> void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
> {
> - kvfree(pkt->buf);
> + if (pkt->buf_len) {
> + if (pkt->slab_buf)
> + kvfree(pkt->buf);
> + else
> + free_pages((unsigned long)pkt->buf,
> + get_order(pkt->buf_len));
> + }
> +
> kfree(pkt);
> }
> EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
> --
> 2.35.0
