9p/trans_virtio.c: use virtio_add_sgs[]

virtio_add_buf() is going away, replaced with virtio_add_sgs() which
takes multiple terminated scatterlists.

Cc: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 39 insertions, 9 deletions

diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 74dea377fe5b..568d1c9e09ad 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");
 
@@ -266,14 +275,19 @@ 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) {
@@ -289,7 +303,7 @@ 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 +365,12 @@ 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 +411,22 @@ 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;
+
+        if (out_pages) {
+                sgs[out_sgs++] = chan->sg + out;
                 out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
                                       out_pages, out_nr_pages, uodata, outlen);
+        }
+                
         /*
          * Take care of in data
          * For example TREAD have 11.
@@ -412,11 +436,17 @@ 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;
+
+        if (in_pages) {
+                sgs[out_sgs + in_sgs++] = chan->sg + out + in;
                 in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
                                      in_pages, in_nr_pages, uidata, inlen);
+        }
 
-        err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc,
+        BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs));
+        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;
                 }