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    Subject[PATCH 16/16] 9p/trans_virtio.c: use virtio_add_sgs[]
    Date
    virtio_add_buf() is going away, replaced with virtio_add_sgs() which
    takes multiple terminated scatterlists.

    Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
    ---
    net/9p/trans_virtio.c | 48 +++++++++++++++++++++++++++++++++++++++---------
    1 file changed, 39 insertions(+), 9 deletions(-)

    diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
    index fd05c81..11d5f46 100644
    --- a/net/9p/trans_virtio.c
    +++ b/net/9p/trans_virtio.c
    @@ -194,11 +194,14 @@ static int pack_sg_list(struct scatterlist *sg, int start,
    if (s > count)
    s = count;
    BUG_ON(index > limit);
    + /* Make sure we don't terminate early. */
    + sg_unmark_end(&sg[index]);
    sg_set_buf(&sg[index++], data, s);
    count -= s;
    data += s;
    }
    -
    + if (index-start)
    + sg_mark_end(&sg[index - 1]);
    return index-start;
    }

    @@ -236,12 +239,17 @@ pack_sg_list_p(struct scatterlist *sg, int start, int limit,
    s = rest_of_page(data);
    if (s > count)
    s = count;
    + /* Make sure we don't terminate early. */
    + sg_unmark_end(&sg[index]);
    sg_set_page(&sg[index++], pdata[i++], s, data_off);
    data_off = 0;
    data += s;
    count -= s;
    nr_pages--;
    }
    +
    + if (index-start)
    + sg_mark_end(&sg[index - 1]);
    return index - start;
    }

    @@ -256,9 +264,10 @@ static int
    p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
    {
    int err;
    - int in, out;
    + int in, out, out_sgs, in_sgs;
    unsigned long flags;
    struct virtio_chan *chan = client->trans;
    + struct scatterlist *sgs[2];

    p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n");

    @@ -266,15 +275,21 @@ p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
    req_retry:
    spin_lock_irqsave(&chan->lock, flags);

    + out_sgs = in_sgs = 0;
    /* Handle out VirtIO ring buffers */
    out = pack_sg_list(chan->sg, 0,
    VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);
    + if (out)
    + sgs[out_sgs++] = chan->sg;

    in = pack_sg_list(chan->sg, out,
    VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity);
    + if (in)
    + sgs[out_sgs + in_sgs++] = chan->sg + out;

    - err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc,
    + err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc,
    GFP_ATOMIC);
    +
    if (err < 0) {
    if (err == -ENOSPC) {
    chan->ring_bufs_avail = 0;
    @@ -289,7 +304,7 @@ req_retry:
    } else {
    spin_unlock_irqrestore(&chan->lock, flags);
    p9_debug(P9_DEBUG_TRANS,
    - "virtio rpc add_buf returned failure\n");
    + "virtio rpc add_sgs returned failure\n");
    return -EIO;
    }
    }
    @@ -351,11 +366,12 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
    char *uidata, char *uodata, int inlen,
    int outlen, int in_hdr_len, int kern_buf)
    {
    - int in, out, err;
    + int in, out, err, out_sgs, in_sgs;
    unsigned long flags;
    int in_nr_pages = 0, out_nr_pages = 0;
    struct page **in_pages = NULL, **out_pages = NULL;
    struct virtio_chan *chan = client->trans;
    + struct scatterlist *sgs[4];

    p9_debug(P9_DEBUG_TRANS, "virtio request\n");

    @@ -396,13 +412,22 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
    req->status = REQ_STATUS_SENT;
    req_retry_pinned:
    spin_lock_irqsave(&chan->lock, flags);
    +
    + out_sgs = in_sgs = 0;
    +
    /* out data */
    out = pack_sg_list(chan->sg, 0,
    VIRTQUEUE_NUM, req->tc->sdata, req->tc->size);

    - if (out_pages)
    + if (out)
    + sgs[out_sgs++] = chan->sg + out;
    +
    + if (out_pages) {
    out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
    out_pages, out_nr_pages, uodata, outlen);
    + sgs[out_sgs++] = chan->sg + out;
    + }
    +
    /*
    * Take care of in data
    * For example TREAD have 11.
    @@ -412,11 +437,16 @@ req_retry_pinned:
    */
    in = pack_sg_list(chan->sg, out,
    VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len);
    - if (in_pages)
    + if (in)
    + sgs[out_sgs + in_sgs++] = chan->sg + out + in;
    +
    + if (in_pages) {
    in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
    in_pages, in_nr_pages, uidata, inlen);
    + sgs[out_sgs + in_sgs++] = chan->sg + out + in;
    + }

    - err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc,
    + err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc,
    GFP_ATOMIC);
    if (err < 0) {
    if (err == -ENOSPC) {
    @@ -432,7 +462,7 @@ req_retry_pinned:
    } else {
    spin_unlock_irqrestore(&chan->lock, flags);
    p9_debug(P9_DEBUG_TRANS,
    - "virtio rpc add_buf returned failure\n");
    + "virtio rpc add_sgs returned failure\n");
    err = -EIO;
    goto err_out;
    }
    --
    1.7.10.4


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