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>
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index aa1a3d5..d739ee4 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -139,7 +139,7 @@
}
}
- if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr)) {
+ if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) {
mempool_free(vbr, vblk->pool);
return false;
}
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index 32216b6..b6c24dc 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -51,7 +51,7 @@
sg_init_one(&sg, random_data+data_left, RANDOM_DATA_SIZE-data_left);
/* There should always be room for one buffer. */
- if (vq->vq_ops->add_buf(vq, &sg, 0, 1, random_data) != 0)
+ if (vq->vq_ops->add_buf(vq, &sg, 0, 1, random_data) < 0)
BUG();
vq->vq_ops->kick(vq);
}
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index c74dacf..a035ae3 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -65,7 +65,7 @@
/* add_buf wants a token to identify this buffer: we hand it any
* non-NULL pointer, since there's only ever one buffer. */
- if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, (void *)1) == 0) {
+ if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, (void *)1) >= 0) {
/* Tell Host to go! */
out_vq->vq_ops->kick(out_vq);
/* Chill out until it's done with the buffer. */
@@ -85,7 +85,7 @@
sg_init_one(sg, inbuf, PAGE_SIZE);
/* We should always be able to add one buffer to an empty queue. */
- if (in_vq->vq_ops->add_buf(in_vq, sg, 0, 1, inbuf) != 0)
+ if (in_vq->vq_ops->add_buf(in_vq, sg, 0, 1, inbuf) < 0)
BUG();
in_vq->vq_ops->kick(in_vq);
}
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 32266fb..fbf04a5 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -320,7 +320,7 @@
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 @@
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 @@
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 @@
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 @@
/* 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 @@
/* 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 @@
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);
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 26b2782..3978923 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -84,7 +84,7 @@
init_completion(&vb->acked);
/* We should always be able to add one buffer to an empty queue. */
- if (vq->vq_ops->add_buf(vq, &sg, 1, 0, vb) != 0)
+ if (vq->vq_ops->add_buf(vq, &sg, 1, 0, vb) < 0)
BUG();
vq->vq_ops->kick(vq);
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index a882f26..f536005 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -208,7 +208,11 @@
pr_debug("Added buffer head %i to %p\n", head, vq);
END_USE(vq);
- return 0;
+
+ /* If we're indirect, we can fit many (assuming not OOM). */
+ if (vq->indirect)
+ return vq->num_free ? vq->vring.num : 0;
+ return vq->num_free;
}
static void vring_kick(struct virtqueue *_vq)
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 4fca4f5..057a2e0 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -34,7 +34,7 @@
* out_num: the number of sg readable by other side
* in_num: the number of sg which are writable (after readable ones)
* data: the token identifying the buffer.
- * Returns 0 or an error.
+ * Returns remaining capacity of queue (sg segments) or a negative error.
* @kick: update after add_buf
* vq: the struct virtqueue
* After one or more add_buf calls, invoke this to kick the other side.
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 9bf0b73..53c139d 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -200,7 +200,7 @@
req->status = REQ_STATUS_SENT;
- if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, req->tc)) {
+ if (chan->vq->vq_ops->add_buf(chan->vq, chan->sg, out, in, req->tc) < 0) {
P9_DPRINTK(P9_DEBUG_TRANS,
"9p debug: virtio rpc add_buf returned failure");
return -EIO;