From: Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: netdev <netdev@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 1/3] virtio_net: pass well-formed sgs to virtqueue_add_*()
Date: Tue, 14 Oct 2014 12:51:47 +1030 [thread overview]
Message-ID: <877g03crwk.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20140907072032.GA25143@redhat.com>
"Michael S. Tsirkin" <mst@redhat.com> writes:
> On Fri, Sep 05, 2014 at 12:40:50PM +0200, Paolo Bonzini wrote:
>> Il 03/09/2014 06:29, Rusty Russell ha scritto:
>> > + sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
>>
>> I think 2 is enough here. That said...
>>
>> > sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr);
>> > -
>> > skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
>> >
>> > err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
>>
>> ... skb_to_sgvec will already make the sg well formed, so the
>> sg_init_table is _almost_ redundant; it is only there to remove
>> intermediate end marks. The block layer takes care to remove
>> them, but skb_to_sgvec doesn't.
sg_init_table is still needed if CONFIG_DEBUG_SG, so I don't
think it's worth it.
Thanks,
Rusty.
next prev parent reply other threads:[~2014-10-14 2:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1409718556-3041-1-git-send-email-rusty@rustcorp.com.au>
2014-09-03 4:29 ` [PATCH 1/3] virtio_net: pass well-formed sgs to virtqueue_add_*() Rusty Russell
2014-09-05 10:40 ` Paolo Bonzini
2014-09-07 7:20 ` Michael S. Tsirkin
2014-10-14 2:21 ` Rusty Russell [this message]
2014-09-03 4:29 ` [PATCH 2/3] virtio_ring: assume sgs are always well-formed Rusty Russell
2014-09-03 4:29 ` [PATCH 3/3] virtio_ring: unify direct/indirect code paths Rusty Russell
2014-09-04 1:59 ` Andy Lutomirski
2014-09-05 2:55 ` Rusty Russell
2014-09-05 10:55 ` Paolo Bonzini
2014-09-08 17:32 ` Andy Lutomirski
[not found] ` <1409718556-3041-2-git-send-email-rusty@rustcorp.com.au>
2014-09-03 4:54 ` [PATCH 1/3] virtio_net: pass well-formed sgs to virtqueue_add_*() Andy Lutomirski
2014-09-03 10:23 ` Jesper Dangaard Brouer
2014-09-05 21:27 ` [PATCH 0/3] virtio: simplify virtio_ring David Miller
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