virtio: make add_buf return capacity remaining

This API change means that virtio_net can tell how much capacity
remains for buffers.  It's necessarily fuzzy, since
VIRTIO_RING_F_INDIRECT_DESC means we can fit any number of descriptors
in one, *if* we can kmalloc.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 32266fb89c20..fbf04a553f5a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -320,7 +320,7 @@ static bool try_fill_recv_maxbufs(struct virtnet_info *vi, gfp_t gfp)
                 skb_queue_head(&vi->recv, skb);
 
                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
-                if (err) {
+                if (err < 0) {
                         skb_unlink(skb, &vi->recv);
                         trim_pages(vi, skb);
                         kfree_skb(skb);
@@ -373,7 +373,7 @@ static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
                 skb_queue_head(&vi->recv, skb);
 
                 err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 1, skb);
-                if (err) {
+                if (err < 0) {
                         skb_unlink(skb, &vi->recv);
                         kfree_skb(skb);
                         break;
@@ -527,7 +527,7 @@ static int xmit_skb(struct virtnet_info *vi, struct sk_buff *skb)
         num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
 
         err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
-        if (!err && !vi->free_in_tasklet)
+        if (err >= 0 && !vi->free_in_tasklet)
                 mod_timer(&vi->xmit_free_timer, jiffies + (HZ/10));
 
         return err;
@@ -538,7 +538,7 @@ static void xmit_tasklet(unsigned long data)
         struct virtnet_info *vi = (void *)data;
 
         netif_tx_lock_bh(vi->dev);
-        if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) == 0) {
+        if (vi->last_xmit_skb && xmit_skb(vi, vi->last_xmit_skb) >= 0) {
                 vi->svq->vq_ops->kick(vi->svq);
                 vi->last_xmit_skb = NULL;
         }
@@ -557,7 +557,7 @@ again:
 
         /* If we has a buffer left over from last time, send it now. */
         if (unlikely(vi->last_xmit_skb) &&
-            xmit_skb(vi, vi->last_xmit_skb) != 0)
+            xmit_skb(vi, vi->last_xmit_skb) < 0)
                 goto stop_queue;
 
         vi->last_xmit_skb = NULL;
@@ -565,7 +565,7 @@ again:
         /* Put new one in send queue and do transmit */
         if (likely(skb)) {
                 __skb_queue_head(&vi->send, skb);
-                if (xmit_skb(vi, skb) != 0) {
+                if (xmit_skb(vi, skb) < 0) {
                         vi->last_xmit_skb = skb;
                         skb = NULL;
                         goto stop_queue;
@@ -668,7 +668,7 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
                 sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
         sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
 
-        BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi));
+        BUG_ON(vi->cvq->vq_ops->add_buf(vi->cvq, sg, out, in, vi) < 0);
 
         vi->cvq->vq_ops->kick(vi->cvq);