vhost: Cleanup vhost.c and net.c

Minor cleanup of vhost.c and net.c to match coding style. Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

vhost: Cleanup vhost.c and net.c
Minor cleanup of vhost.c and net.c to match coding style. Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Krishna Kumar · Michael S. Tsirkin
1 parent 1fc050a134
Showing 2 changed files with 49 additions and 23 deletions Side-by-side Diff
drivers/vhost/net.c
drivers/vhost/vhost.c
@@ -60,6 +60,7 @@
 {
 	int seg = 0;
 	size_t size;
+
 	while (len && seg < iov_count) {
 		size = min(from->iov_len, len);
 		to->iov_base = from->iov_base;
@@ -79,6 +80,7 @@
 {
 	int seg = 0;
 	size_t size;
+
 	while (len && seg < iovcount) {
 		size = min(from->iov_len, len);
 		to->iov_base = from->iov_base;
  
  
@@ -296,17 +298,16 @@
 		.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;
  
  
  
@@ -405,18 +406,17 @@
 		.msg_iov = vq->iov,
 		.msg_flags = MSG_DONTWAIT,
 	};
-
 	struct virtio_net_hdr_mrg_rxbuf hdr = {
 		.hdr.flags = 0,
 		.hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
 	};
-
 	size_t total_len = 0;
 	int err, headcount;
 	size_t vhost_hlen, sock_hlen;
 	size_t vhost_len, sock_len;
 	/* 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;
  
@@ -654,6 +654,7 @@
 	} uaddr;
 	int uaddr_len = sizeof uaddr, r;
 	struct socket *sock = sockfd_lookup(fd, &r);
+
 	if (!sock)
 		return ERR_PTR(-ENOTSOCK);
  
@@ -682,6 +683,7 @@
 {
 	struct file *file = fget(fd);
 	struct socket *sock;
+
 	if (!file)
 		return ERR_PTR(-EBADF);
 	sock = tun_get_socket(file);
@@ -696,6 +698,7 @@
 static struct socket *get_socket(int fd)
 {
 	struct socket *sock;
+
 	/* special case to disable backend */
 	if (fd == -1)
 		return NULL;
@@ -741,9 +744,9 @@
 	oldsock = rcu_dereference_protected(vq->private_data,
 					    lockdep_is_held(&vq->mutex));
 	if (sock != oldsock) {
-                vhost_net_disable_vq(n, vq);
-                rcu_assign_pointer(vq->private_data, sock);
-                vhost_net_enable_vq(n, vq);
+		vhost_net_disable_vq(n, vq);
+		rcu_assign_pointer(vq->private_data, sock);
+		vhost_net_enable_vq(n, vq);
 	}
  
 	mutex_unlock(&vq->mutex);
@@ -768,6 +771,7 @@
 	struct socket *tx_sock = NULL;
 	struct socket *rx_sock = NULL;
 	long err;
+
 	mutex_lock(&n->dev.mutex);
 	err = vhost_dev_check_owner(&n->dev);
 	if (err)
@@ -829,6 +833,7 @@
 	struct vhost_vring_file backend;
 	u64 features;
 	int r;
+
 	switch (ioctl) {
 	case VHOST_NET_SET_BACKEND:
 		if (copy_from_user(&backend, argp, sizeof backend))
@@ -41,8 +41,8 @@
 			    poll_table *pt)
 {
 	struct vhost_poll *poll;
-	poll = container_of(pt, struct vhost_poll, table);
  
+	poll = container_of(pt, struct vhost_poll, table);
 	poll->wqh = wqh;
 	add_wait_queue(wqh, &poll->wait);
 }
@@ -85,6 +85,7 @@
 void vhost_poll_start(struct vhost_poll *poll, struct file *file)
 {
 	unsigned long mask;
+
 	mask = file->f_op->poll(file, &poll->table);
 	if (mask)
 		vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
@@ -101,6 +102,7 @@
 				unsigned seq)
 {
 	int left;
+
 	spin_lock_irq(&dev->work_lock);
 	left = seq - work->done_seq;
 	spin_unlock_irq(&dev->work_lock);
@@ -222,6 +224,7 @@
 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
 {
 	int i;
+
 	for (i = 0; i < dev->nvqs; ++i) {
 		dev->vqs[i].indirect = kmalloc(sizeof *dev->vqs[i].indirect *
 					       UIO_MAXIOV, GFP_KERNEL);
@@ -235,6 +238,7 @@
 			goto err_nomem;
 	}
 	return 0;
+
 err_nomem:
 	for (; i >= 0; --i) {
 		kfree(dev->vqs[i].indirect);
@@ -247,6 +251,7 @@
 static void vhost_dev_free_iovecs(struct vhost_dev *dev)
 {
 	int i;
+
 	for (i = 0; i < dev->nvqs; ++i) {
 		kfree(dev->vqs[i].indirect);
 		dev->vqs[i].indirect = NULL;
  
  
@@ -296,26 +301,28 @@
 }
  
 struct vhost_attach_cgroups_struct {
-        struct vhost_work work;
-        struct task_struct *owner;
-        int ret;
+	struct vhost_work work;
+	struct task_struct *owner;
+	int ret;
 };
  
 static void vhost_attach_cgroups_work(struct vhost_work *work)
 {
-        struct vhost_attach_cgroups_struct *s;
-        s = container_of(work, struct vhost_attach_cgroups_struct, work);
-        s->ret = cgroup_attach_task_all(s->owner, current);
+	struct vhost_attach_cgroups_struct *s;
+
+	s = container_of(work, struct vhost_attach_cgroups_struct, work);
+	s->ret = cgroup_attach_task_all(s->owner, current);
 }
  
 static int vhost_attach_cgroups(struct vhost_dev *dev)
 {
-        struct vhost_attach_cgroups_struct attach;
-        attach.owner = current;
-        vhost_work_init(&attach.work, vhost_attach_cgroups_work);
-        vhost_work_queue(dev, &attach.work);
-        vhost_work_flush(dev, &attach.work);
-        return attach.ret;
+	struct vhost_attach_cgroups_struct attach;
+
+	attach.owner = current;
+	vhost_work_init(&attach.work, vhost_attach_cgroups_work);
+	vhost_work_queue(dev, &attach.work);
+	vhost_work_flush(dev, &attach.work);
+	return attach.ret;
 }
  
 /* Caller should have device mutex */
  
@@ -323,11 +330,13 @@
 {
 	struct task_struct *worker;
 	int err;
+
 	/* Is there an owner already? */
 	if (dev->mm) {
 		err = -EBUSY;
 		goto err_mm;
 	}
+
 	/* No owner, become one */
 	dev->mm = get_task_mm(current);
 	worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
@@ -380,6 +389,7 @@
 void vhost_dev_cleanup(struct vhost_dev *dev)
 {
 	int i;
+
 	for (i = 0; i < dev->nvqs; ++i) {
 		if (dev->vqs[i].kick && dev->vqs[i].handle_kick) {
 			vhost_poll_stop(&dev->vqs[i].poll);
@@ -421,6 +431,7 @@
 static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
 {
 	u64 a = addr / VHOST_PAGE_SIZE / 8;
+
 	/* Make sure 64 bit math will not overflow. */
 	if (a > ULONG_MAX - (unsigned long)log_base ||
 	    a + (unsigned long)log_base > ULONG_MAX)
@@ -461,6 +472,7 @@
 			    int log_all)
 {
 	int i;
+
 	for (i = 0; i < d->nvqs; ++i) {
 		int ok;
 		mutex_lock(&d->vqs[i].mutex);
@@ -527,6 +539,7 @@
 {
 	struct vhost_memory mem, *newmem, *oldmem;
 	unsigned long size = offsetof(struct vhost_memory, regions);
+
 	if (copy_from_user(&mem, m, size))
 		return -EFAULT;
 	if (mem.padding)
@@ -544,7 +557,8 @@
 		return -EFAULT;
 	}
  
-	if (!memory_access_ok(d, newmem, vhost_has_feature(d, VHOST_F_LOG_ALL))) {
+	if (!memory_access_ok(d, newmem,
+			      vhost_has_feature(d, VHOST_F_LOG_ALL))) {
 		kfree(newmem);
 		return -EFAULT;
 	}
@@ -560,6 +574,7 @@
 		     struct vring_used __user *used)
 {
 	int r = put_user(vq->used_flags, &used->flags);
+
 	if (r)
 		return r;
 	return get_user(vq->last_used_idx, &used->idx);
@@ -849,6 +864,7 @@
 {
 	struct vhost_memory_region *reg;
 	int i;
+
 	/* linear search is not brilliant, but we really have on the order of 6
 	 * regions in practice */
 	for (i = 0; i < mem->nregions; ++i) {
@@ -871,6 +887,7 @@
 	void *base;
 	int bit = nr + (log % PAGE_SIZE) * 8;
 	int r;
+
 	r = get_user_pages_fast(log, 1, 1, &page);
 	if (r < 0)
 		return r;
@@ -888,6 +905,7 @@
 {
 	u64 write_page = write_address / VHOST_PAGE_SIZE;
 	int r;
+
 	if (!write_length)
 		return 0;
 	write_length += write_address % VHOST_PAGE_SIZE;
@@ -1037,8 +1055,8 @@
 			       i, count);
 			return -EINVAL;
 		}
-		if (unlikely(memcpy_fromiovec((unsigned char *)&desc, vq->indirect,
-					      sizeof desc))) {
+		if (unlikely(memcpy_fromiovec((unsigned char *)&desc,
+					      vq->indirect, sizeof desc))) {
 			vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
 			       i, (size_t)indirect->addr + i * sizeof desc);
 			return -EINVAL;
@@ -1317,6 +1335,7 @@
 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 {
 	__u16 flags;
+
 	/* Flush out used index updates. This is paired
 	 * with the barrier that the Guest executes when enabling
 	 * interrupts. */
@@ -1361,6 +1380,7 @@
 {
 	u16 avail_idx;
 	int r;
+
 	if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
 		return false;
 	vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
@@ -1387,6 +1407,7 @@
 void vhost_disable_notify(struct vhost_virtqueue *vq)
 {
 	int r;
+
 	if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
 		return;
 	vq->used_flags |= VRING_USED_F_NO_NOTIFY;
...	...	@@ -60,6 +60,7 @@
60	60	{
61	61	int seg = 0;
62	62	size_t size;
	63	+
63	64	while (len && seg < iov_count) {
64	65	size = min(from->iov_len, len);
65	66	to->iov_base = from->iov_base;
...	...	@@ -79,6 +80,7 @@
79	80	{
80	81	int seg = 0;
81	82	size_t size;
	83	+
82	84	while (len && seg < iovcount) {
83	85	size = min(from->iov_len, len);
84	86	to->iov_base = from->iov_base;
85	87
86	88
...	...	@@ -296,17 +298,16 @@
296	298	.msg_iov = vq->iov,
297	299	.msg_flags = MSG_DONTWAIT,
298	300	};
299		-
300	301	struct virtio_net_hdr hdr = {
301	302	.flags = 0,
302	303	.gso_type = VIRTIO_NET_HDR_GSO_NONE
303	304	};
304		-
305	305	size_t len, total_len = 0;
306	306	int err;
307	307	size_t hdr_size;
308	308	/* TODO: check that we are running from vhost_worker? */
309	309	struct socket *sock = rcu_dereference_check(vq->private_data, 1);
	310	+
310	311	if (!sock \|\| skb_queue_empty(&sock->sk->sk_receive_queue))
311	312	return;
312	313
313	314
314	315
...	...	@@ -405,18 +406,17 @@
405	406	.msg_iov = vq->iov,
406	407	.msg_flags = MSG_DONTWAIT,
407	408	};
408		-
409	409	struct virtio_net_hdr_mrg_rxbuf hdr = {
410	410	.hdr.flags = 0,
411	411	.hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
412	412	};
413		-
414	413	size_t total_len = 0;
415	414	int err, headcount;
416	415	size_t vhost_hlen, sock_hlen;
417	416	size_t vhost_len, sock_len;
418	417	/* TODO: check that we are running from vhost_worker? */
419	418	struct socket *sock = rcu_dereference_check(vq->private_data, 1);
	419	+
420	420	if (!sock \|\| skb_queue_empty(&sock->sk->sk_receive_queue))
421	421	return;
422	422
...	...	@@ -654,6 +654,7 @@
654	654	} uaddr;
655	655	int uaddr_len = sizeof uaddr, r;
656	656	struct socket *sock = sockfd_lookup(fd, &r);
	657	+
657	658	if (!sock)
658	659	return ERR_PTR(-ENOTSOCK);
659	660
...	...	@@ -682,6 +683,7 @@
682	683	{
683	684	struct file *file = fget(fd);
684	685	struct socket *sock;
	686	+
685	687	if (!file)
686	688	return ERR_PTR(-EBADF);
687	689	sock = tun_get_socket(file);
...	...	@@ -696,6 +698,7 @@
696	698	static struct socket *get_socket(int fd)
697	699	{
698	700	struct socket *sock;
	701	+
699	702	/* special case to disable backend */
700	703	if (fd == -1)
701	704	return NULL;
...	...	@@ -741,9 +744,9 @@
741	744	oldsock = rcu_dereference_protected(vq->private_data,
742	745	lockdep_is_held(&vq->mutex));
743	746	if (sock != oldsock) {
744		- vhost_net_disable_vq(n, vq);
745		- rcu_assign_pointer(vq->private_data, sock);
746		- vhost_net_enable_vq(n, vq);
	747	+ vhost_net_disable_vq(n, vq);
	748	+ rcu_assign_pointer(vq->private_data, sock);
	749	+ vhost_net_enable_vq(n, vq);
747	750	}
748	751
749	752	mutex_unlock(&vq->mutex);
...	...	@@ -768,6 +771,7 @@
768	771	struct socket *tx_sock = NULL;
769	772	struct socket *rx_sock = NULL;
770	773	long err;
	774	+
771	775	mutex_lock(&n->dev.mutex);
772	776	err = vhost_dev_check_owner(&n->dev);
773	777	if (err)
...	...	@@ -829,6 +833,7 @@
829	833	struct vhost_vring_file backend;
830	834	u64 features;
831	835	int r;
	836	+
832	837	switch (ioctl) {
833	838	case VHOST_NET_SET_BACKEND:
834	839	if (copy_from_user(&backend, argp, sizeof backend))
...	...	@@ -41,8 +41,8 @@
41	41	poll_table *pt)
42	42	{
43	43	struct vhost_poll *poll;
44		- poll = container_of(pt, struct vhost_poll, table);
45	44
	45	+ poll = container_of(pt, struct vhost_poll, table);
46	46	poll->wqh = wqh;
47	47	add_wait_queue(wqh, &poll->wait);
48	48	}
...	...	@@ -85,6 +85,7 @@
85	85	void vhost_poll_start(struct vhost_poll poll, struct file file)
86	86	{
87	87	unsigned long mask;
	88	+
88	89	mask = file->f_op->poll(file, &poll->table);
89	90	if (mask)
90	91	vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
...	...	@@ -101,6 +102,7 @@
101	102	unsigned seq)
102	103	{
103	104	int left;
	105	+
104	106	spin_lock_irq(&dev->work_lock);
105	107	left = seq - work->done_seq;
106	108	spin_unlock_irq(&dev->work_lock);
...	...	@@ -222,6 +224,7 @@
222	224	static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
223	225	{
224	226	int i;
	227	+
225	228	for (i = 0; i < dev->nvqs; ++i) {
226	229	dev->vqs[i].indirect = kmalloc(sizeof dev->vqs[i].indirect
227	230	UIO_MAXIOV, GFP_KERNEL);
...	...	@@ -235,6 +238,7 @@
235	238	goto err_nomem;
236	239	}
237	240	return 0;
	241	+
238	242	err_nomem:
239	243	for (; i >= 0; --i) {
240	244	kfree(dev->vqs[i].indirect);
...	...	@@ -247,6 +251,7 @@
247	251	static void vhost_dev_free_iovecs(struct vhost_dev *dev)
248	252	{
249	253	int i;
	254	+
250	255	for (i = 0; i < dev->nvqs; ++i) {
251	256	kfree(dev->vqs[i].indirect);
252	257	dev->vqs[i].indirect = NULL;
253	258
254	259
...	...	@@ -296,26 +301,28 @@
296	301	}
297	302
298	303	struct vhost_attach_cgroups_struct {
299		- struct vhost_work work;
300		- struct task_struct *owner;
301		- int ret;
	304	+ struct vhost_work work;
	305	+ struct task_struct *owner;
	306	+ int ret;
302	307	};
303	308
304	309	static void vhost_attach_cgroups_work(struct vhost_work *work)
305	310	{
306		- struct vhost_attach_cgroups_struct *s;
307		- s = container_of(work, struct vhost_attach_cgroups_struct, work);
308		- s->ret = cgroup_attach_task_all(s->owner, current);
	311	+ struct vhost_attach_cgroups_struct *s;
	312	+
	313	+ s = container_of(work, struct vhost_attach_cgroups_struct, work);
	314	+ s->ret = cgroup_attach_task_all(s->owner, current);
309	315	}
310	316
311	317	static int vhost_attach_cgroups(struct vhost_dev *dev)
312	318	{
313		- struct vhost_attach_cgroups_struct attach;
314		- attach.owner = current;
315		- vhost_work_init(&attach.work, vhost_attach_cgroups_work);
316		- vhost_work_queue(dev, &attach.work);
317		- vhost_work_flush(dev, &attach.work);
318		- return attach.ret;
	319	+ struct vhost_attach_cgroups_struct attach;
	320	+
	321	+ attach.owner = current;
	322	+ vhost_work_init(&attach.work, vhost_attach_cgroups_work);
	323	+ vhost_work_queue(dev, &attach.work);
	324	+ vhost_work_flush(dev, &attach.work);
	325	+ return attach.ret;
319	326	}
320	327
321	328	/* Caller should have device mutex */
322	329
...	...	@@ -323,11 +330,13 @@
323	330	{
324	331	struct task_struct *worker;
325	332	int err;
	333	+
326	334	/* Is there an owner already? */
327	335	if (dev->mm) {
328	336	err = -EBUSY;
329	337	goto err_mm;
330	338	}
	339	+
331	340	/* No owner, become one */
332	341	dev->mm = get_task_mm(current);
333	342	worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
...	...	@@ -380,6 +389,7 @@
380	389	void vhost_dev_cleanup(struct vhost_dev *dev)
381	390	{
382	391	int i;
	392	+
383	393	for (i = 0; i < dev->nvqs; ++i) {
384	394	if (dev->vqs[i].kick && dev->vqs[i].handle_kick) {
385	395	vhost_poll_stop(&dev->vqs[i].poll);
...	...	@@ -421,6 +431,7 @@
421	431	static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
422	432	{
423	433	u64 a = addr / VHOST_PAGE_SIZE / 8;
	434	+
424	435	/* Make sure 64 bit math will not overflow. */
425	436	if (a > ULONG_MAX - (unsigned long)log_base \|\|
426	437	a + (unsigned long)log_base > ULONG_MAX)
...	...	@@ -461,6 +472,7 @@
461	472	int log_all)
462	473	{
463	474	int i;
	475	+
464	476	for (i = 0; i < d->nvqs; ++i) {
465	477	int ok;
466	478	mutex_lock(&d->vqs[i].mutex);
...	...	@@ -527,6 +539,7 @@
527	539	{
528	540	struct vhost_memory mem, newmem, oldmem;
529	541	unsigned long size = offsetof(struct vhost_memory, regions);
	542	+
530	543	if (copy_from_user(&mem, m, size))
531	544	return -EFAULT;
532	545	if (mem.padding)
...	...	@@ -544,7 +557,8 @@
544	557	return -EFAULT;
545	558	}
546	559
547		- if (!memory_access_ok(d, newmem, vhost_has_feature(d, VHOST_F_LOG_ALL))) {
	560	+ if (!memory_access_ok(d, newmem,
	561	+ vhost_has_feature(d, VHOST_F_LOG_ALL))) {
548	562	kfree(newmem);
549	563	return -EFAULT;
550	564	}
...	...	@@ -560,6 +574,7 @@
560	574	struct vring_used __user *used)
561	575	{
562	576	int r = put_user(vq->used_flags, &used->flags);
	577	+
563	578	if (r)
564	579	return r;
565	580	return get_user(vq->last_used_idx, &used->idx);
...	...	@@ -849,6 +864,7 @@
849	864	{
850	865	struct vhost_memory_region *reg;
851	866	int i;
	867	+
852	868	/* linear search is not brilliant, but we really have on the order of 6
853	869	* regions in practice */
854	870	for (i = 0; i < mem->nregions; ++i) {
...	...	@@ -871,6 +887,7 @@
871	887	void *base;
872	888	int bit = nr + (log % PAGE_SIZE) * 8;
873	889	int r;
	890	+
874	891	r = get_user_pages_fast(log, 1, 1, &page);
875	892	if (r < 0)
876	893	return r;
...	...	@@ -888,6 +905,7 @@
888	905	{
889	906	u64 write_page = write_address / VHOST_PAGE_SIZE;
890	907	int r;
	908	+
891	909	if (!write_length)
892	910	return 0;
893	911	write_length += write_address % VHOST_PAGE_SIZE;
...	...	@@ -1037,8 +1055,8 @@
1037	1055	i, count);
1038	1056	return -EINVAL;
1039	1057	}
1040		- if (unlikely(memcpy_fromiovec((unsigned char *)&desc, vq->indirect,
1041		- sizeof desc))) {
	1058	+ if (unlikely(memcpy_fromiovec((unsigned char *)&desc,
	1059	+ vq->indirect, sizeof desc))) {
1042	1060	vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
1043	1061	i, (size_t)indirect->addr + i * sizeof desc);
1044	1062	return -EINVAL;
...	...	@@ -1317,6 +1335,7 @@
1317	1335	void vhost_signal(struct vhost_dev dev, struct vhost_virtqueue vq)
1318	1336	{
1319	1337	__u16 flags;
	1338	+
1320	1339	/* Flush out used index updates. This is paired
1321	1340	* with the barrier that the Guest executes when enabling
1322	1341	* interrupts. */
...	...	@@ -1361,6 +1380,7 @@
1361	1380	{
1362	1381	u16 avail_idx;
1363	1382	int r;
	1383	+
1364	1384	if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
1365	1385	return false;
1366	1386	vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
...	...	@@ -1387,6 +1407,7 @@
1387	1407	void vhost_disable_notify(struct vhost_virtqueue *vq)
1388	1408	{
1389	1409	int r;
	1410	+
1390	1411	if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
1391	1412	return;
1392	1413	vq->used_flags \|= VRING_USED_F_NO_NOTIFY;