vhost-net: Unify the code of mergeable and big buffer handling

Codes duplication were found between the handling of mergeable and big buffers, so this patch tries to unify them. This could be easily done by adding a quota to the get_rx_bufs() which is used to limit the number of buffers it returns (for mergeable buffer, the quota is simply UIO_MAXIOV, for big buffers, the quota is just 1), and then the previous handle_rx_mergeable() could be resued also for big buffers. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

vhost-net: Unify the code of mergeable and big buffer handling
Codes duplication were found between the handling of mergeable and big buffers, so this patch tries to unify them. This could be easily done by adding a quota to the get_rx_bufs() which is used to limit the number of buffers it returns (for mergeable buffer, the quota is simply UIO_MAXIOV, for big buffers, the quota is just 1), and then the previous handle_rx_mergeable() could be resued also for big buffers. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Jason Wang · Michael S. Tsirkin
1 parent cfbdab9513
Showing 1 changed file with 7 additions and 121 deletions Side-by-side Diff
drivers/vhost/net.c
@@ -229,6 +229,7 @@
  * @iovcount	- returned count of io vectors we fill
  * @log		- vhost log
  * @log_num	- log offset
+ * @quota       - headcount quota, 1 for big buffer
  *	returns number of buffer heads allocated, negative on error
  */
 static int get_rx_bufs(struct vhost_virtqueue *vq,
@@ -236,7 +237,8 @@
 		       int datalen,
 		       unsigned *iovcount,
 		       struct vhost_log *log,
-		       unsigned *log_num)
+		       unsigned *log_num,
+		       unsigned int quota)
 {
 	unsigned int out, in;
 	int seg = 0;
@@ -244,7 +246,7 @@
 	unsigned d;
 	int r, nlogs = 0;
  
-	while (datalen > 0) {
+	while (datalen > 0 && headcount < quota) {
 		if (unlikely(seg >= UIO_MAXIOV)) {
 			r = -ENOBUFS;
 			goto err;
  
@@ -284,118 +286,9 @@
  
 /* Expects to be always run from workqueue - which acts as
  * read-size critical section for our kind of RCU. */
-static void handle_rx_big(struct vhost_net *net)
+static void handle_rx(struct vhost_net *net)
 {
 	struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
-	unsigned out, in, log, s;
-	int head;
-	struct vhost_log *vq_log;
-	struct msghdr msg = {
-		.msg_name = NULL,
-		.msg_namelen = 0,
-		.msg_control = NULL, /* FIXME: get and handle RX aux data. */
-		.msg_controllen = 0,
-		.msg_iov = vq->iov,
-		.msg_flags = MSG_DONTWAIT,
-	};
-	struct virtio_net_hdr hdr = {
-		.flags = 0,
-		.gso_type = VIRTIO_NET_HDR_GSO_NONE
-	};
-	size_t len, total_len = 0;
-	int err;
-	size_t hdr_size;
-	/* TODO: check that we are running from vhost_worker? */
-	struct socket *sock = rcu_dereference_check(vq->private_data, 1);
-
-	if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue))
-		return;
-
-	mutex_lock(&vq->mutex);
-	vhost_disable_notify(vq);
-	hdr_size = vq->vhost_hlen;
-
-	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);
-		/* On error, stop handling until the next kick. */
-		if (unlikely(head < 0))
-			break;
-		/* OK, now we need to know about added descriptors. */
-		if (head == vq->num) {
-			if (unlikely(vhost_enable_notify(vq))) {
-				/* They have slipped one in as we were
-				 * doing that: check again. */
-				vhost_disable_notify(vq);
-				continue;
-			}
-			/* Nothing new?  Wait for eventfd to tell us
-			 * 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;
-		len = iov_length(vq->iov, in);
-		/* Sanity check */
-		if (!len) {
-			vq_err(vq, "Unexpected header len for RX: "
-			       "%zd expected %zd\n",
-			       iov_length(vq->hdr, s), hdr_size);
-			break;
-		}
-		err = sock->ops->recvmsg(NULL, sock, &msg,
-					 len, MSG_DONTWAIT | MSG_TRUNC);
-		/* TODO: Check specific error and bomb out unless EAGAIN? */
-		if (err < 0) {
-			vhost_discard_vq_desc(vq, 1);
-			break;
-		}
-		/* TODO: Should check and handle checksum. */
-		if (err > len) {
-			pr_debug("Discarded truncated rx packet: "
-				 " len %d > %zd\n", err, len);
-			vhost_discard_vq_desc(vq, 1);
-			continue;
-		}
-		len = err;
-		err = memcpy_toiovec(vq->hdr, (unsigned char *)&hdr, hdr_size);
-		if (err) {
-			vq_err(vq, "Unable to write vnet_hdr at addr %p: %d\n",
-			       vq->iov->iov_base, err);
-			break;
-		}
-		len += hdr_size;
-		vhost_add_used_and_signal(&net->dev, vq, head, len);
-		if (unlikely(vq_log))
-			vhost_log_write(vq, vq_log, log, len);
-		total_len += len;
-		if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
-			vhost_poll_queue(&vq->poll);
-			break;
-		}
-	}
-
-	mutex_unlock(&vq->mutex);
-}
-
-/* Expects to be always run from workqueue - which acts as
- * read-size critical section for our kind of RCU. */
-static void handle_rx_mergeable(struct vhost_net *net)
-{
-	struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
 	unsigned uninitialized_var(in), log;
 	struct vhost_log *vq_log;
 	struct msghdr msg = {
@@ -433,7 +326,8 @@
 		sock_len += sock_hlen;
 		vhost_len = sock_len + vhost_hlen;
 		headcount = get_rx_bufs(vq, vq->heads, vhost_len,
-					&in, vq_log, &log);
+					&in, vq_log, &log,
+					likely(mergeable) ? UIO_MAXIOV : 1);
 		/* On error, stop handling until the next kick. */
 		if (unlikely(headcount < 0))
 			break;
@@ -497,14 +391,6 @@
 	}
  
 	mutex_unlock(&vq->mutex);
-}
-
-static void handle_rx(struct vhost_net *net)
-{
-	if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF))
-		handle_rx_mergeable(net);
-	else
-		handle_rx_big(net);
 }
  
 static void handle_tx_kick(struct vhost_work *work)
...	...	@@ -229,6 +229,7 @@
229	229	* @iovcount - returned count of io vectors we fill
230	230	* @log - vhost log
231	231	* @log_num - log offset
	232	+ * @quota - headcount quota, 1 for big buffer
232	233	* returns number of buffer heads allocated, negative on error
233	234	*/
234	235	static int get_rx_bufs(struct vhost_virtqueue *vq,
...	...	@@ -236,7 +237,8 @@
236	237	int datalen,
237	238	unsigned *iovcount,
238	239	struct vhost_log *log,
239		- unsigned *log_num)
	240	+ unsigned *log_num,
	241	+ unsigned int quota)
240	242	{
241	243	unsigned int out, in;
242	244	int seg = 0;
...	...	@@ -244,7 +246,7 @@
244	246	unsigned d;
245	247	int r, nlogs = 0;
246	248
247		- while (datalen > 0) {
	249	+ while (datalen > 0 && headcount < quota) {
248	250	if (unlikely(seg >= UIO_MAXIOV)) {
249	251	r = -ENOBUFS;
250	252	goto err;
251	253
...	...	@@ -284,118 +286,9 @@
284	286
285	287	/* Expects to be always run from workqueue - which acts as
286	288	* read-size critical section for our kind of RCU. */
287		-static void handle_rx_big(struct vhost_net *net)
	289	+static void handle_rx(struct vhost_net *net)
288	290	{
289	291	struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
290		- unsigned out, in, log, s;
291		- int head;
292		- struct vhost_log *vq_log;
293		- struct msghdr msg = {
294		- .msg_name = NULL,
295		- .msg_namelen = 0,
296		- .msg_control = NULL, /* FIXME: get and handle RX aux data. */
297		- .msg_controllen = 0,
298		- .msg_iov = vq->iov,
299		- .msg_flags = MSG_DONTWAIT,
300		- };
301		- struct virtio_net_hdr hdr = {
302		- .flags = 0,
303		- .gso_type = VIRTIO_NET_HDR_GSO_NONE
304		- };
305		- size_t len, total_len = 0;
306		- int err;
307		- size_t hdr_size;
308		- /* TODO: check that we are running from vhost_worker? */
309		- struct socket *sock = rcu_dereference_check(vq->private_data, 1);
310		-
311		- if (!sock \|\| skb_queue_empty(&sock->sk->sk_receive_queue))
312		- return;
313		-
314		- mutex_lock(&vq->mutex);
315		- vhost_disable_notify(vq);
316		- hdr_size = vq->vhost_hlen;
317		-
318		- vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
319		- vq->log : NULL;
320		-
321		- for (;;) {
322		- head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
323		- ARRAY_SIZE(vq->iov),
324		- &out, &in,
325		- vq_log, &log);
326		- /* On error, stop handling until the next kick. */
327		- if (unlikely(head < 0))
328		- break;
329		- /* OK, now we need to know about added descriptors. */
330		- if (head == vq->num) {
331		- if (unlikely(vhost_enable_notify(vq))) {
332		- /* They have slipped one in as we were
333		- * doing that: check again. */
334		- vhost_disable_notify(vq);
335		- continue;
336		- }
337		- /* Nothing new? Wait for eventfd to tell us
338		- * they refilled. */
339		- break;
340		- }
341		- /* We don't need to be notified again. */
342		- if (out) {
343		- vq_err(vq, "Unexpected descriptor format for RX: "
344		- "out %d, int %d\n",
345		- out, in);
346		- break;
347		- }
348		- /* Skip header. TODO: support TSO/mergeable rx buffers. */
349		- s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, in);
350		- msg.msg_iovlen = in;
351		- len = iov_length(vq->iov, in);
352		- /* Sanity check */
353		- if (!len) {
354		- vq_err(vq, "Unexpected header len for RX: "
355		- "%zd expected %zd\n",
356		- iov_length(vq->hdr, s), hdr_size);
357		- break;
358		- }
359		- err = sock->ops->recvmsg(NULL, sock, &msg,
360		- len, MSG_DONTWAIT \| MSG_TRUNC);
361		- /* TODO: Check specific error and bomb out unless EAGAIN? */
362		- if (err < 0) {
363		- vhost_discard_vq_desc(vq, 1);
364		- break;
365		- }
366		- /* TODO: Should check and handle checksum. */
367		- if (err > len) {
368		- pr_debug("Discarded truncated rx packet: "
369		- " len %d > %zd\n", err, len);
370		- vhost_discard_vq_desc(vq, 1);
371		- continue;
372		- }
373		- len = err;
374		- err = memcpy_toiovec(vq->hdr, (unsigned char *)&hdr, hdr_size);
375		- if (err) {
376		- vq_err(vq, "Unable to write vnet_hdr at addr %p: %d\n",
377		- vq->iov->iov_base, err);
378		- break;
379		- }
380		- len += hdr_size;
381		- vhost_add_used_and_signal(&net->dev, vq, head, len);
382		- if (unlikely(vq_log))
383		- vhost_log_write(vq, vq_log, log, len);
384		- total_len += len;
385		- if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
386		- vhost_poll_queue(&vq->poll);
387		- break;
388		- }
389		- }
390		-
391		- mutex_unlock(&vq->mutex);
392		-}
393		-
394		-/* Expects to be always run from workqueue - which acts as
395		- * read-size critical section for our kind of RCU. */
396		-static void handle_rx_mergeable(struct vhost_net *net)
397		-{
398		- struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
399	292	unsigned uninitialized_var(in), log;
400	293	struct vhost_log *vq_log;
401	294	struct msghdr msg = {
...	...	@@ -433,7 +326,8 @@
433	326	sock_len += sock_hlen;
434	327	vhost_len = sock_len + vhost_hlen;
435	328	headcount = get_rx_bufs(vq, vq->heads, vhost_len,
436		- &in, vq_log, &log);
	329	+ &in, vq_log, &log,
	330	+ likely(mergeable) ? UIO_MAXIOV : 1);
437	331	/* On error, stop handling until the next kick. */
438	332	if (unlikely(headcount < 0))
439	333	break;
...	...	@@ -497,14 +391,6 @@
497	391	}
498	392
499	393	mutex_unlock(&vq->mutex);
500		-}
501		-
502		-static void handle_rx(struct vhost_net *net)
503		-{
504		- if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF))
505		- handle_rx_mergeable(net);
506		- else
507		- handle_rx_big(net);
508	394	}
509	395
510	396	static void handle_tx_kick(struct vhost_work *work)