netdev - Re: [PATCH net-next v2 06/13] virtio-net: rq submits premapped per-buffer

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CACGkMEviCSEo4thkFo8gYnv+FCm-v65umJ65fdOwtxbAF_F2Ag@mail.gmail.com>
Date: Tue, 5 Nov 2024 11:23:50 +0800
From: Jason Wang <jasowang@...hat.com>
To: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
Cc: netdev@...r.kernel.org, "Michael S. Tsirkin" <mst@...hat.com>, 
	Eugenio Pérez <eperezma@...hat.com>, 
	Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Alexei Starovoitov <ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>, 
	Jesper Dangaard Brouer <hawk@...nel.org>, John Fastabend <john.fastabend@...il.com>, 
	virtualization@...ts.linux.dev, bpf@...r.kernel.org
Subject: Re: [PATCH net-next v2 06/13] virtio-net: rq submits premapped per-buffer

On Wed, Oct 30, 2024 at 4:25 PM Xuan Zhuo <xuanzhuo@...ux.alibaba.com> wrote:
>
> virtio-net rq submits premapped per-buffer by setting sg page to NULL;
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
> ---
>  drivers/net/virtio_net.c | 24 +++++++++++++-----------
>  1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 792e9eadbfc3..09757fa408bd 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -542,6 +542,12 @@ static struct sk_buff *ptr_to_skb(void *ptr)
>         return (struct sk_buff *)((unsigned long)ptr & ~VIRTIO_ORPHAN_FLAG);
>  }
>
> +static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
> +{
> +       sg->dma_address = addr;
> +       sg->length = len;

This may work but I think it's better to reuse existing dma sg helpers like:

sg_dma_address(sg) = addr;
sg_dma_length(sg) = len;

And we probably need to fix the virtio core which only uses
sg_dma_address() but not sg_dma_length().

This helps us to avoid future issues when CONFIG_NEED_SG_DMA_LENGTH is set.

Others look good.

Thanks

> +}
> +
>  static void __free_old_xmit(struct send_queue *sq, struct netdev_queue *txq,
>                             bool in_napi, struct virtnet_sq_free_stats *stats)
>  {
> @@ -915,8 +921,7 @@ static void virtnet_rq_init_one_sg(struct receive_queue *rq, void *buf, u32 len)
>         addr = dma->addr - sizeof(*dma) + offset;
>
>         sg_init_table(rq->sg, 1);
> -       rq->sg[0].dma_address = addr;
> -       rq->sg[0].length = len;
> +       sg_fill_dma(rq->sg, addr, len);
>  }
>
>  static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size, gfp_t gfp)
> @@ -1068,12 +1073,6 @@ static void check_sq_full_and_disable(struct virtnet_info *vi,
>         }
>  }
>
> -static void sg_fill_dma(struct scatterlist *sg, dma_addr_t addr, u32 len)
> -{
> -       sg->dma_address = addr;
> -       sg->length = len;
> -}
> -
>  static struct xdp_buff *buf_to_xdp(struct virtnet_info *vi,
>                                    struct receive_queue *rq, void *buf, u32 len)
>  {
> @@ -1354,7 +1353,8 @@ static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct receive_queue
>                 sg_init_table(rq->sg, 1);
>                 sg_fill_dma(rq->sg, addr, len);
>
> -               err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, xsk_buffs[i], gfp);
> +               err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, xsk_buffs[i],
> +                                                   NULL, true, gfp);
>                 if (err)
>                         goto err;
>         }
> @@ -2431,7 +2431,8 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
>
>         virtnet_rq_init_one_sg(rq, buf, vi->hdr_len + GOOD_PACKET_LEN);
>
> -       err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
> +       err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx,
> +                                           rq->do_dma, gfp);
>         if (err < 0) {
>                 if (rq->do_dma)
>                         virtnet_rq_unmap(rq, buf, 0);
> @@ -2546,7 +2547,8 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
>         virtnet_rq_init_one_sg(rq, buf, len);
>
>         ctx = mergeable_len_to_ctx(len + room, headroom);
> -       err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
> +       err = virtqueue_add_inbuf_premapped(rq->vq, rq->sg, 1, buf, ctx,
> +                                           rq->do_dma, gfp);
>         if (err < 0) {
>                 if (rq->do_dma)
>                         virtnet_rq_unmap(rq, buf, 0);
> --
> 2.32.0.3.g01195cf9f
>