[PATCH v15 15/17] Provides multiple submits and asynchronous notifications.

From: xiaohui . xin
Date: Tue Nov 09 2010 - 03:43:09 EST

From: Xin Xiaohui <xiaohui.xin@xxxxxxxxx>

The vhost-net backend now only supports synchronous send/recv
operations. The patch provides multiple submits and asynchronous
notifications. This is needed for zero-copy case.

Signed-off-by: Xin Xiaohui <xiaohui.xin@xxxxxxxxx>
---
drivers/vhost/net.c | 355 +++++++++++++++++++++++++++++++++++++++++++++----
drivers/vhost/vhost.c | 78 +++++++++++
drivers/vhost/vhost.h | 15 ++-
3 files changed, 423 insertions(+), 25 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 7c80082..17c599a 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -24,6 +24,8 @@
#include <linux/if_arp.h>
#include <linux/if_tun.h>
#include <linux/if_macvlan.h>
+#include <linux/mpassthru.h>
+#include <linux/aio.h>

#include <net/sock.h>

@@ -32,6 +34,7 @@
/* Max number of bytes transferred before requeueing the job.
* Using this limit prevents one virtqueue from starving others. */
#define VHOST_NET_WEIGHT 0x80000
+static struct kmem_cache *notify_cache;

enum {
VHOST_NET_VQ_RX = 0,
@@ -49,6 +52,7 @@ struct vhost_net {
struct vhost_dev dev;
struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX];
struct vhost_poll poll[VHOST_NET_VQ_MAX];
+ struct kmem_cache *cache;
/* Tells us whether we are polling a socket for TX.
* We only do this when socket buffer fills up.
* Protected by tx vq lock. */
@@ -109,11 +113,184 @@ static void tx_poll_start(struct vhost_net *net, struct socket *sock)
net->tx_poll_state = VHOST_NET_POLL_STARTED;
}

+struct kiocb *notify_dequeue(struct vhost_virtqueue *vq)
+{
+ struct kiocb *iocb = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&vq->notify_lock, flags);
+ if (!list_empty(&vq->notifier)) {
+ iocb = list_first_entry(&vq->notifier,
+ struct kiocb, ki_list);
+ list_del(&iocb->ki_list);
+ }
+ spin_unlock_irqrestore(&vq->notify_lock, flags);
+ return iocb;
+}
+
+static void handle_iocb(struct kiocb *iocb)
+{
+ struct vhost_virtqueue *vq = iocb->private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&vq->notify_lock, flags);
+ list_add_tail(&iocb->ki_list, &vq->notifier);
+ spin_unlock_irqrestore(&vq->notify_lock, flags);
+}
+
+static int is_async_vq(struct vhost_virtqueue *vq)
+{
+ return (vq->link_state == VHOST_VQ_LINK_ASYNC);
+}
+
+static void handle_async_rx_events_notify(struct vhost_net *net,
+ struct vhost_virtqueue *vq,
+ struct socket *sock)
+{
+ struct kiocb *iocb = NULL;
+ struct vhost_log *vq_log = NULL;
+ int rx_total_len = 0;
+ unsigned int head, log, in, out;
+ int size;
+
+ if (!is_async_vq(vq))
+ return;
+
+ if (sock->sk->sk_data_ready)
+ sock->sk->sk_data_ready(sock->sk, 0);
+
+ vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
+ vq->log : NULL;
+
+ while ((iocb = notify_dequeue(vq)) != NULL) {
+ if (!iocb->ki_left) {
+ vhost_add_used_and_signal(&net->dev, vq,
+ iocb->ki_pos, iocb->ki_nbytes);
+ size = iocb->ki_nbytes;
+ head = iocb->ki_pos;
+ rx_total_len += iocb->ki_nbytes;
+
+ if (iocb->ki_dtor)
+ iocb->ki_dtor(iocb);
+ kmem_cache_free(net->cache, iocb);
+
+ /* when log is enabled, recomputing the log is needed,
+ * since these buffers are in async queue, may not get
+ * the log info before.
+ */
+ if (unlikely(vq_log)) {
+ if (!log)
+ __vhost_get_vq_desc(&net->dev, vq,
+ vq->iov,
+ ARRAY_SIZE(vq->iov),
+ &out, &in, vq_log,
+ &log, head);
+ vhost_log_write(vq, vq_log, log, size);
+ }
+ if (unlikely(rx_total_len >= VHOST_NET_WEIGHT)) {
+ vhost_poll_queue(&vq->poll);
+ break;
+ }
+ } else {
+ int i = 0;
+ int count = iocb->ki_left;
+ int hc = count;
+ while (count--) {
+ if (iocb) {
+ vq->heads[i].id = iocb->ki_pos;
+ vq->heads[i].len = iocb->ki_nbytes;
+ size = iocb->ki_nbytes;
+ head = iocb->ki_pos;
+ rx_total_len += iocb->ki_nbytes;
+
+ if (iocb->ki_dtor)
+ iocb->ki_dtor(iocb);
+ kmem_cache_free(net->cache, iocb);
+
+ if (unlikely(vq_log)) {
+ if (!log)
+ __vhost_get_vq_desc(
+ &net->dev, vq, vq->iov,
+ ARRAY_SIZE(vq->iov),
+ &out, &in, vq_log,
+ &log, head);
+ vhost_log_write(
+ vq, vq_log, log, size);
+ }
+ } else
+ break;
+
+ i++;
+ if (count)
+ iocb = notify_dequeue(vq);
+ }
+ vhost_add_used_and_signal_n(
+ &net->dev, vq, vq->heads, hc);
+ }
+ }
+}
+
+static void handle_async_tx_events_notify(struct vhost_net *net,
+ struct vhost_virtqueue *vq)
+{
+ struct kiocb *iocb = NULL;
+ struct list_head *entry, *tmp;
+ unsigned long flags;
+ int tx_total_len = 0;
+
+ if (!is_async_vq(vq))
+ return;
+
+ spin_lock_irqsave(&vq->notify_lock, flags);
+ list_for_each_safe(entry, tmp, &vq->notifier) {
+ iocb = list_entry(entry,
+ struct kiocb, ki_list);
+ if (!iocb->ki_flags)
+ continue;
+ list_del(&iocb->ki_list);
+ vhost_add_used_and_signal(&net->dev, vq,
+ iocb->ki_pos, 0);
+ tx_total_len += iocb->ki_nbytes;
+
+ if (iocb->ki_dtor)
+ iocb->ki_dtor(iocb);
+
+ kmem_cache_free(net->cache, iocb);
+ if (unlikely(tx_total_len >= VHOST_NET_WEIGHT)) {
+ vhost_poll_queue(&vq->poll);
+ break;
+ }
+ }
+ spin_unlock_irqrestore(&vq->notify_lock, flags);
+}
+
+static struct kiocb *create_iocb(struct vhost_net *net,
+ struct vhost_virtqueue *vq,
+ unsigned head)
+{
+ struct kiocb *iocb = NULL;
+
+ if (!is_async_vq(vq))
+ return NULL;
+
+ iocb = kmem_cache_zalloc(net->cache, GFP_KERNEL);
+ if (!iocb)
+ return NULL;
+ iocb->private = vq;
+ iocb->ki_pos = head;
+ iocb->ki_dtor = handle_iocb;
+ if (vq == &net->dev.vqs[VHOST_NET_VQ_RX])
+ iocb->ki_user_data = vq->num;
+ iocb->ki_iovec = vq->hdr;
+ return iocb;
+}
+
/* Expects to be always run from workqueue - which acts as
* read-size critical section for our kind of RCU. */
static void handle_tx(struct vhost_net *net)
{
struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
+ struct kiocb *iocb = NULL;
unsigned out, in, s;
int head;
struct msghdr msg = {
@@ -146,6 +323,10 @@ static void handle_tx(struct vhost_net *net)
if (wmem < sock->sk->sk_sndbuf / 2)
tx_poll_stop(net);
hdr_size = vq->vhost_hlen;
+ if (!vq->vhost_hlen && is_async_vq(vq))
+ hdr_size = vq->sock_hlen;
+
+ handle_async_tx_events_notify(net, vq);

for (;;) {
head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
@@ -157,11 +338,14 @@ static void handle_tx(struct vhost_net *net)
break;
/* Nothing new? Wait for eventfd to tell us they refilled. */
if (head == vq->num) {
- wmem = atomic_read(&sock->sk->sk_wmem_alloc);
- if (wmem >= sock->sk->sk_sndbuf * 3 / 4) {
- tx_poll_start(net, sock);
- set_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
- break;
+ if (!is_async_vq(vq)) {
+ wmem = atomic_read(&sock->sk->sk_wmem_alloc);
+ if (wmem >= sock->sk->sk_sndbuf * 3 / 4) {
+ tx_poll_start(net, sock);
+ set_bit(SOCK_ASYNC_NOSPACE,
+ &sock->flags);
+ break;
+ }
}
if (unlikely(vhost_enable_notify(vq))) {
vhost_disable_notify(vq);
@@ -178,6 +362,13 @@ static void handle_tx(struct vhost_net *net)
s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out);
msg.msg_iovlen = out;
len = iov_length(vq->iov, out);
+ /* if async operations supported */
+ if (is_async_vq(vq)) {
+ iocb = create_iocb(net, vq, head);
+ if (!iocb)
+ break;
+ }
+
/* Sanity check */
if (!len) {
vq_err(vq, "Unexpected header len for TX: "
@@ -186,12 +377,18 @@ static void handle_tx(struct vhost_net *net)
break;
}
/* TODO: Check specific error and bomb out unless ENOBUFS? */
- err = sock->ops->sendmsg(NULL, sock, &msg, len);
+ err = sock->ops->sendmsg(iocb, sock, &msg, len);
if (unlikely(err < 0)) {
+ if (is_async_vq(vq))
+ kmem_cache_free(net->cache, iocb);
vhost_discard_vq_desc(vq, 1);
tx_poll_start(net, sock);
break;
}
+
+ if (is_async_vq(vq))
+ continue;
+
if (err != len)
pr_debug("Truncated TX packet: "
" len %d != %zd\n", err, len);
@@ -203,6 +400,8 @@ static void handle_tx(struct vhost_net *net)
}
}

+ handle_async_tx_events_notify(net, vq);
+
mutex_unlock(&vq->mutex);
unuse_mm(net->dev.mm);
}
@@ -396,7 +595,8 @@ static void handle_rx_big(struct vhost_net *net)
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;
+ unsigned uninitialized_var(in), log, out;
+ struct kiocb *iocb;
struct vhost_log *vq_log;
struct msghdr msg = {
.msg_name = NULL,
@@ -417,28 +617,44 @@ static void handle_rx_mergeable(struct vhost_net *net)
size_t vhost_hlen, sock_hlen;
size_t vhost_len, sock_len;
struct socket *sock = rcu_dereference(vq->private_data);
- if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue))
+ if (!sock || (skb_queue_empty(&sock->sk->sk_receive_queue) &&
+ !is_async_vq(vq)))
return;
-
use_mm(net->dev.mm);
mutex_lock(&vq->mutex);
vhost_disable_notify(vq);
vhost_hlen = vq->vhost_hlen;
sock_hlen = vq->sock_hlen;

+ /* In async cases, when write log is enabled, in case the submitted
+ * buffers did not get log info before the log enabling, so we'd
+ * better recompute the log info when needed. We do this in
+ * handle_async_rx_events_notify().
+ */
+
vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
vq->log : NULL;

- while ((sock_len = peek_head_len(sock->sk))) {
- sock_len += sock_hlen;
- vhost_len = sock_len + vhost_hlen;
- headcount = get_rx_bufs(vq, vq->heads, vhost_len,
+ handle_async_rx_events_notify(net, vq, sock);
+
+ while (is_async_vq(vq) || (sock_len = peek_head_len(sock->sk))) {
+ if (is_async_vq(vq))
+ headcount = vhost_get_vq_desc(&net->dev, vq, vq->iov,
+ ARRAY_SIZE(vq->iov),
+ &out, &in,
+ vq->log, &log);
+ else {
+ sock_len += sock_hlen;
+ vhost_len = sock_len + vhost_hlen;
+ headcount = get_rx_bufs(vq, vq->heads, vhost_len,
&in, vq_log, &log);
+ }
/* On error, stop handling until the next kick. */
if (unlikely(headcount < 0))
break;
/* OK, now we need to know about added descriptors. */
- if (!headcount) {
+ if ((!headcount && !is_async_vq(vq)) ||
+ (headcount == vq->num && is_async_vq(vq))) {
if (unlikely(vhost_enable_notify(vq))) {
/* They have slipped one in as we were
* doing that: check again. */
@@ -450,16 +666,41 @@ static void handle_rx_mergeable(struct vhost_net *net)
break;
}
/* We don't need to be notified again. */
- if (unlikely((vhost_hlen)))
- /* Skip header. TODO: support TSO. */
- move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in);
- else
- /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF:
- * needed because sendmsg can modify msg_iov. */
- copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in);
+ if (unlikely((vhost_hlen))) {
+ if (is_async_vq(vq))
+ vq->hdr[0].iov_len = vhost_hlen;
+ else
+ /* Skip header. TODO: support TSO. */
+ move_iovec_hdr(vq->iov, vq->hdr,
+ vhost_hlen, in);
+ } else {
+ if (is_async_vq(vq))
+ vq->hdr[0].iov_len = sock_hlen;
+ else
+ /* Copy the header for use in
+ * VIRTIO_NET_F_MRG_RXBUF:
+ * needed because sendmsg can
+ * modify msg_iov. */
+ copy_iovec_hdr(vq->iov, vq->hdr,
+ sock_hlen, in);
+ }
msg.msg_iovlen = in;
- err = sock->ops->recvmsg(NULL, sock, &msg,
+ if (is_async_vq(vq)) {
+ iocb = create_iocb(net, vq, headcount);
+ if (!iocb)
+ break;
+ }
+ err = sock->ops->recvmsg(iocb, sock, &msg,
sock_len, MSG_DONTWAIT | MSG_TRUNC);
+ if (is_async_vq(vq)) {
+ if (err < 0) {
+ kmem_cache_free(net->cache, iocb);
+ vhost_discard_vq_desc(vq, headcount);
+ break;
+ }
+ continue;
+ }
+
/* Userspace might have consumed the packet meanwhile:
* it's not supposed to do this usually, but might be hard
* to prevent. Discard data we got (if any) and keep going. */
@@ -496,6 +737,8 @@ static void handle_rx_mergeable(struct vhost_net *net)
}
}

+ handle_async_rx_events_notify(net, vq, sock);
+
mutex_unlock(&vq->mutex);
unuse_mm(net->dev.mm);
}
@@ -561,6 +804,7 @@ static int vhost_net_open(struct inode *inode, struct file *f)
vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev);
vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev);
n->tx_poll_state = VHOST_NET_POLL_DISABLED;
+ n->cache = NULL;

f->private_data = n;

@@ -624,6 +868,21 @@ static void vhost_net_flush(struct vhost_net *n)
vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
}

+static void vhost_async_cleanup(struct vhost_net *n)
+{
+ /* clean the notifier */
+ struct vhost_virtqueue *vq;
+ struct kiocb *iocb = NULL;
+ if (n->cache) {
+ vq = &n->dev.vqs[VHOST_NET_VQ_RX];
+ while ((iocb = notify_dequeue(vq)) != NULL)
+ kmem_cache_free(n->cache, iocb);
+ vq = &n->dev.vqs[VHOST_NET_VQ_TX];
+ while ((iocb = notify_dequeue(vq)) != NULL)
+ kmem_cache_free(n->cache, iocb);
+ }
+}
+
static int vhost_net_release(struct inode *inode, struct file *f)
{
struct vhost_net *n = f->private_data;
@@ -640,6 +899,7 @@ static int vhost_net_release(struct inode *inode, struct file *f)
/* We do an extra flush before freeing memory,
* since jobs can re-queue themselves. */
vhost_net_flush(n);
+ vhost_async_cleanup(n);
kfree(n);
return 0;
}
@@ -691,21 +951,61 @@ static struct socket *get_tap_socket(int fd)
return sock;
}

-static struct socket *get_socket(int fd)
+static struct socket *get_mp_socket(int fd)
+{
+ struct file *file = fget(fd);
+ struct socket *sock;
+ if (!file)
+ return ERR_PTR(-EBADF);
+ sock = mp_get_socket(file);
+ if (IS_ERR(sock))
+ fput(file);
+ return sock;
+}
+
+static struct socket *get_socket(struct vhost_virtqueue *vq, int fd,
+ enum vhost_vq_link_state *state)
{
struct socket *sock;
/* special case to disable backend */
if (fd == -1)
return NULL;
+
+ *state = VHOST_VQ_LINK_SYNC;
+
sock = get_raw_socket(fd);
if (!IS_ERR(sock))
return sock;
sock = get_tap_socket(fd);
if (!IS_ERR(sock))
return sock;
+ /* If we dont' have notify_cache, then dont do mpassthru */
+ if (!notify_cache)
+ return ERR_PTR(-ENOTSOCK);
+ /* If we don't have mergeable buffer then dont do mpassthru */
+ if (vhost_has_feature(vq->dev, VIRTIO_NET_F_MRG_RXBUF)) {
+ sock = get_mp_socket(fd);
+ if (!IS_ERR(sock)) {
+ *state = VHOST_VQ_LINK_ASYNC;
+ return sock;
+ }
+ }
return ERR_PTR(-ENOTSOCK);
}

+static void vhost_init_link_state(struct vhost_net *n, int index)
+{
+ struct vhost_virtqueue *vq = n->vqs + index;
+
+ WARN_ON(!mutex_is_locked(&vq->mutex));
+ if (vq->link_state == VHOST_VQ_LINK_ASYNC) {
+ INIT_LIST_HEAD(&vq->notifier);
+ spin_lock_init(&vq->notify_lock);
+ if (!n->cache)
+ n->cache = notify_cache;
+ }
+}
+
static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
{
struct socket *sock, *oldsock;
@@ -729,12 +1029,14 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
r = -EFAULT;
goto err_vq;
}
- sock = get_socket(fd);
+ sock = get_socket(vq, fd, &vq->link_state);
if (IS_ERR(sock)) {
r = PTR_ERR(sock);
goto err_vq;
}

+ vhost_init_link_state(n, index);
+
/* start polling new socket */
oldsock = vq->private_data;
if (sock != oldsock) {
@@ -879,6 +1181,9 @@ static struct miscdevice vhost_net_misc = {

static int vhost_net_init(void)
{
+ notify_cache = kmem_cache_create("vhost_kiocb",
+ sizeof(struct kiocb), 0,
+ SLAB_HWCACHE_ALIGN, NULL);
return misc_register(&vhost_net_misc);
}
module_init(vhost_net_init);
@@ -886,6 +1191,8 @@ module_init(vhost_net_init);
static void vhost_net_exit(void)
{
misc_deregister(&vhost_net_misc);
+ if (notify_cache)
+ kmem_cache_destroy(notify_cache);
}
module_exit(vhost_net_exit);

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index dd3d6f7..295d9ab 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1015,6 +1015,84 @@ static int get_indirect(struct vhost_dev *dev, struct vhost_virtqueue *vq,
return 0;
}

+/* To recompute the log */
+int __vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
+ struct iovec iov[], unsigned int iov_size,
+ unsigned int *out_num, unsigned int *in_num,
+ struct vhost_log *log, unsigned int *log_num,
+ unsigned int head)
+{
+ struct vring_desc desc;
+ unsigned int i, found = 0;
+ int ret;
+
+ /* When we start there are none of either input nor output. */
+ *out_num = *in_num = 0;
+ if (unlikely(log))
+ *log_num = 0;
+
+ i = head;
+ do {
+ unsigned iov_count = *in_num + *out_num;
+ if (unlikely(i >= vq->num)) {
+ vq_err(vq, "Desc index is %u > %u, head = %u",
+ i, vq->num, head);
+ return -EINVAL;
+ }
+ if (unlikely(++found > vq->num)) {
+ vq_err(vq, "Loop detected: last one at %u "
+ "vq size %u head %u\n",
+ i, vq->num, head);
+ return -EINVAL;
+ }
+ ret = copy_from_user(&desc, vq->desc + i, sizeof desc);
+ if (unlikely(ret)) {
+ vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
+ i, vq->desc + i);
+ return -EFAULT;
+ }
+ if (desc.flags & VRING_DESC_F_INDIRECT) {
+ ret = get_indirect(dev, vq, iov, iov_size,
+ out_num, in_num,
+ log, log_num, &desc);
+ if (unlikely(ret < 0)) {
+ vq_err(vq, "Failure detected "
+ "in indirect descriptor at idx %d\n", i);
+ return ret;
+ }
+ continue;
+ }
+
+ ret = translate_desc(dev, desc.addr, desc.len, iov + iov_count,
+ iov_size - iov_count);
+ if (unlikely(ret < 0)) {
+ vq_err(vq, "Translation failure %d descriptor idx %d\n",
+ ret, i);
+ return ret;
+ }
+ if (desc.flags & VRING_DESC_F_WRITE) {
+ /* If this is an input descriptor,
+ * increment that count. */
+ *in_num += ret;
+ if (unlikely(log)) {
+ log[*log_num].addr = desc.addr;
+ log[*log_num].len = desc.len;
+ ++*log_num;
+ }
+ } else {
+ /* If it's an output descriptor, they're all supposed
+ * to come before any input descriptors. */
+ if (unlikely(*in_num)) {
+ vq_err(vq, "Descriptor has out after in: "
+ "idx %d\n", i);
+ return -EINVAL;
+ }
+ *out_num += ret;
+ }
+ } while ((i = next_desc(&desc)) != -1);
+
+ return head;
+}
/* 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
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index afd7729..915336d 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -55,6 +55,11 @@ struct vhost_log {
u64 len;
};

+enum vhost_vq_link_state {
+ VHOST_VQ_LINK_SYNC = 0,
+ VHOST_VQ_LINK_ASYNC = 1,
+};
+
/* The virtqueue structure describes a queue attached to a device. */
struct vhost_virtqueue {
struct vhost_dev *dev;
@@ -110,6 +115,10 @@ struct vhost_virtqueue {
/* Log write descriptors */
void __user *log_base;
struct vhost_log log[VHOST_NET_MAX_SG];
+ /* Differiate async socket for 0-copy from normal */
+ enum vhost_vq_link_state link_state;
+ struct list_head notifier;
+ spinlock_t notify_lock;
};

struct vhost_dev {
@@ -136,7 +145,11 @@ void vhost_dev_cleanup(struct vhost_dev *);
long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
int vhost_vq_access_ok(struct vhost_virtqueue *vq);
int vhost_log_access_ok(struct vhost_dev *);
-
+int __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,
+ unsigned int head);
int 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,
--
1.7.3

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