This patch generalizes buffer handling functions to
support multiple buffer heads.
In-line for viewing, attached for applying.
Signed-off-by: David L Stevens <dlstevens@xxxxxxxxxx>
diff -ruN net-next-p0/drivers/vhost/net.c net-next-p1/drivers/vhost/net.c
--- net-next-p0/drivers/vhost/net.c 2010-02-24 12:59:24.000000000
-0800
+++ net-next-p1/drivers/vhost/net.c 2010-03-01 11:44:22.000000000
-0800
@@ -97,7 +97,8 @@
static void handle_tx(struct vhost_net *net)
{
struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
- unsigned head, out, in, s;
+ unsigned out, in, s;
+ struct iovec head;
struct msghdr msg = {
.msg_name = NULL,
.msg_namelen = 0,
@@ -126,12 +127,10 @@
hdr_size = vq->hdr_size;
for (;;) {
- head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
- ARRAY_SIZE(vq->iov),
- &out, &in,
- NULL, NULL);
+ head.iov_base = (void *)vhost_get_vq_desc(&net->dev, vq,
+ vq->iov, ARRAY_SIZE(vq->iov), &out, &in, NULL,
NULL);
/* Nothing new? Wait for eventfd to tell us they
refilled. */
- if (head == vq->num) {
+ if (head.iov_base == (void *)vq->num) {
wmem = atomic_read(&sock->sk->sk_wmem_alloc);
if (wmem >= sock->sk->sk_sndbuf * 3 / 4) {
tx_poll_start(net, sock);
@@ -152,7 +151,7 @@
/* Skip header. TODO: support TSO. */
s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out);
msg.msg_iovlen = out;
- len = iov_length(vq->iov, out);
+ head.iov_len = len = iov_length(vq->iov, out);
/* Sanity check */
if (!len) {
vq_err(vq, "Unexpected header len for TX: "
@@ -163,14 +162,14 @@
/* TODO: Check specific error and bomb out unless ENOBUFS?
*/
err = sock->ops->sendmsg(NULL, sock, &msg, len);
if (unlikely(err < 0)) {
- vhost_discard_vq_desc(vq);
+ vhost_discard(vq, 1);
tx_poll_start(net, sock);
break;
}
if (err != len)
pr_err("Truncated TX packet: "
" len %d != %zd\n", err, len);
- vhost_add_used_and_signal(&net->dev, vq, head, 0);
+ vhost_add_used_and_signal(&net->dev, vq, &head, 1);
total_len += len;
if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
vhost_poll_queue(&vq->poll);
@@ -182,12 +181,22 @@
unuse_mm(net->dev.mm);
}
+static int skb_head_len(struct sk_buff_head *skq)
+{
+ struct sk_buff *head;
+
+ head = skb_peek(skq);
+ if (head)
+ return head->len;
+ return 0;
+}
+
/* Expects to be always run from workqueue - which acts as
* read-size critical section for our kind of RCU. */
static void handle_rx(struct vhost_net *net)
{
struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
- unsigned head, out, in, log, s;
+ unsigned in, log, s;
struct vhost_log *vq_log;
struct msghdr msg = {
.msg_name = NULL,
@@ -204,10 +213,11 @@
};
size_t len, total_len = 0;
- int err;
+ int err, headcount, datalen;
size_t hdr_size;
struct socket *sock = rcu_dereference(vq->private_data);
- if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue))
+
+ if (!sock || !skb_head_len(&sock->sk->sk_receive_queue))
return;
use_mm(net->dev.mm);
@@ -218,13 +228,10 @@
vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
vq->log : NULL;
- for (;;) {
- head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
- ARRAY_SIZE(vq->iov),
- &out, &in,
- vq_log, &log);
+ while ((datalen = skb_head_len(&sock->sk->sk_receive_queue))) {
+ headcount = vhost_get_heads(vq, datalen, &in, vq_log,
&log);
/* OK, now we need to know about added descriptors. */
- if (head == vq->num) {
+ if (!headcount) {
if (unlikely(vhost_enable_notify(vq))) {
/* They have slipped one in as we were
* doing that: check again. */
@@ -235,13 +242,6 @@
* they refilled. */
break;
}
- /* We don't need to be notified again. */
- if (out) {
- vq_err(vq, "Unexpected descriptor format for RX: "
- "out %d, int %d\n",
- out, in);
- break;
- }
/* Skip header. TODO: support TSO/mergeable rx buffers. */
s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, in);
msg.msg_iovlen = in;
@@ -257,14 +257,14 @@
len, MSG_DONTWAIT | MSG_TRUNC);
/* TODO: Check specific error and bomb out unless EAGAIN?
*/
if (err < 0) {
- vhost_discard_vq_desc(vq);
+ vhost_discard(vq, 1);
break;
}
/* TODO: Should check and handle checksum. */
if (err > len) {
pr_err("Discarded truncated rx packet: "
" len %d > %zd\n", err, len);
- vhost_discard_vq_desc(vq);
+ vhost_discard(vq, 1);
continue;
}
len = err;
@@ -275,7 +275,7 @@
break;
}
len += hdr_size;
- vhost_add_used_and_signal(&net->dev, vq, head, len);
+ vhost_add_used_and_signal(&net->dev, vq, vq->heads,
headcount);
if (unlikely(vq_log))
vhost_log_write(vq, vq_log, log, len);
total_len += len;
diff -ruN net-next-p0/drivers/vhost/vhost.c
net-next-p1/drivers/vhost/vhost.c
--- net-next-p0/drivers/vhost/vhost.c 2010-02-15 20:08:35.000000000
-0800
+++ net-next-p1/drivers/vhost/vhost.c 2010-03-01 11:44:06.000000000
-0800
@@ -848,6 +848,38 @@
return 0;
}
+unsigned vhost_get_heads(struct vhost_virtqueue *vq, int datalen, int
*iovcount,
+ struct vhost_log *log, unsigned int *log_num)
+{
+ struct iovec *heads = vq->heads;
+ int out, in;
+ int hc = 0;
+
+ while (datalen > 0) {
+ if (hc >= VHOST_NET_MAX_SG) {
+ vhost_discard(vq, hc);
+ return 0;
+ }
+ heads[hc].iov_base = (void *)vhost_get_vq_desc(vq->dev,
vq,
+ vq->iov, ARRAY_SIZE(vq->iov), &out, &in, log,
log_num);
+ if (heads[hc].iov_base == (void *)vq->num) {
+ vhost_discard(vq, hc);
+ return 0;
+ }
+ if (out || in <= 0) {
+ vq_err(vq, "unexpected descriptor format for RX: "
+ "out %d, in %d\n", out, in);
+ vhost_discard(vq, hc);
+ return 0;
+ }
+ heads[hc].iov_len = iov_length(vq->iov, in);
+ hc++;
+ datalen -= heads[hc].iov_len;
+ }
+ *iovcount = in;
+ return hc;
+}
+
/* This looks in the virtqueue and for the first available buffer, and
converts
* it to an iovec for convenient access. Since descriptors consist of
some
* number of output then some number of input descriptors, it's actually
two
@@ -973,31 +1005,32 @@
}
/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
-void vhost_discard_vq_desc(struct vhost_virtqueue *vq)
+void vhost_discard(struct vhost_virtqueue *vq, int n)
{
- vq->last_avail_idx--;
+ vq->last_avail_idx -= n;
}
/* After we've used one of their buffers, we tell them about it. We'll
then
* want to notify the guest, using eventfd. */
-int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int
len)
+int vhost_add_used(struct vhost_virtqueue *vq, struct iovec *heads, int
count)
{
struct vring_used_elem *used;
+ int i;
- /* The virtqueue contains a ring of used buffers. Get a pointer
to the
- * next entry in that used ring. */
- used = &vq->used->ring[vq->last_used_idx % vq->num];
- if (put_user(head, &used->id)) {
- vq_err(vq, "Failed to write used id");
- return -EFAULT;
- }
- if (put_user(len, &used->len)) {
- vq_err(vq, "Failed to write used len");
- return -EFAULT;
+ for (i=0; i<count; i++, vq->last_used_idx++) {
+ used = &vq->used->ring[vq->last_used_idx % vq->num];
+ if (put_user((unsigned)heads[i].iov_base, &used->id)) {
+ vq_err(vq, "Failed to write used id");
+ return -EFAULT;
+ }
+ if (put_user(heads[i].iov_len, &used->len)) {
+ vq_err(vq, "Failed to write used len");
+ return -EFAULT;
+ }
}
/* Make sure buffer is written before we update index. */
smp_wmb();
- if (put_user(vq->last_used_idx + 1, &vq->used->idx)) {
+ if (put_user(vq->last_used_idx, &vq->used->idx)) {
vq_err(vq, "Failed to increment used idx");
return -EFAULT;
}
@@ -1011,7 +1044,6 @@
if (vq->log_ctx)
eventfd_signal(vq->log_ctx, 1);
}
- vq->last_used_idx++;
return 0;
}
@@ -1038,9 +1070,9 @@
/* And here's the combo meal deal. Supersize me! */
void vhost_add_used_and_signal(struct vhost_dev *dev,
struct vhost_virtqueue *vq,
- unsigned int head, int len)
+ struct iovec *heads, int count)
{
- vhost_add_used(vq, head, len);
+ vhost_add_used(vq, heads, count);
vhost_signal(dev, vq);
}
diff -ruN net-next-p0/drivers/vhost/vhost.h
net-next-p1/drivers/vhost/vhost.h
--- net-next-p0/drivers/vhost/vhost.h 2010-02-15 20:08:35.000000000
-0800
+++ net-next-p1/drivers/vhost/vhost.h 2010-03-01 11:42:18.000000000
-0800
@@ -84,6 +84,7 @@
struct iovec indirect[VHOST_NET_MAX_SG];
struct iovec iov[VHOST_NET_MAX_SG];
struct iovec hdr[VHOST_NET_MAX_SG];
+ struct iovec heads[VHOST_NET_MAX_SG];
size_t hdr_size;
/* We use a kind of RCU to access private pointer.
* All readers access it from workqueue, which makes it possible
to
@@ -120,16 +121,18 @@
int vhost_vq_access_ok(struct vhost_virtqueue *vq);
int vhost_log_access_ok(struct vhost_dev *);
+unsigned vhost_get_heads(struct vhost_virtqueue *, int datalen, int
*iovcount,
+ struct vhost_log *log, unsigned int *log_num);
unsigned vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
struct iovec iov[], unsigned int iov_count,
unsigned int *out_num, unsigned int *in_num,
struct vhost_log *log, unsigned int *log_num);
-void vhost_discard_vq_desc(struct vhost_virtqueue *);
+void vhost_discard(struct vhost_virtqueue *, int);
-int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
-void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
+int vhost_add_used(struct vhost_virtqueue *, struct iovec *heads, int
count);
void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue
*,
- unsigned int head, int len);
+ struct iovec *heads, int count);
+void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
void vhost_disable_notify(struct vhost_virtqueue *);
bool vhost_enable_notify(struct vhost_virtqueue *);
Attachment:
MRXB1.patch
Description: Binary data
