5 files changed, 515 insertions, 91 deletions

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index f11e6bb5b036..f13e56babe4b 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -74,6 +74,22 @@ static int move_iovec_hdr(struct iovec *from, struct iovec *to,
         }
         return seg;
 }
+/* Copy iovec entries for len bytes from iovec. */
+static void copy_iovec_hdr(const struct iovec *from, struct iovec *to,
+                           size_t len, int iovcount)
+{
+        int seg = 0;
+        size_t size;
+        while (len && seg < iovcount) {
+                size = min(from->iov_len, len);
+                to->iov_base = from->iov_base;
+                to->iov_len = size;
+                len -= size;
+                ++from;
+                ++to;
+                ++seg;
+        }
+}
 
 /* Caller must have TX VQ lock */
 static void tx_poll_stop(struct vhost_net *net)
@@ -129,7 +145,7 @@ static void handle_tx(struct vhost_net *net)
 
         if (wmem < sock->sk->sk_sndbuf / 2)
                 tx_poll_stop(net);
-        hdr_size = vq->hdr_size;
+        hdr_size = vq->vhost_hlen;
 
         for (;;) {
                 head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
@@ -172,7 +188,7 @@ static void handle_tx(struct vhost_net *net)
                 /* 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_desc(vq, 1);
                         tx_poll_start(net, sock);
                         break;
                 }
@@ -191,9 +207,82 @@ static void handle_tx(struct vhost_net *net)
         unuse_mm(net->dev.mm);
 }
 
+static int peek_head_len(struct sock *sk)
+{
+        struct sk_buff *head;
+        int len = 0;
+
+        lock_sock(sk);
+        head = skb_peek(&sk->sk_receive_queue);
+        if (head)
+                len = head->len;
+        release_sock(sk);
+        return len;
+}
+
+/* This is a multi-buffer version of vhost_get_desc, that works if
+ *      vq has read descriptors only.
+ * @vq          - the relevant virtqueue
+ * @datalen     - data length we'll be reading
+ * @iovcount    - returned count of io vectors we fill
+ * @log         - vhost log
+ * @log_num     - log offset
+ *      returns number of buffer heads allocated, negative on error
+ */
+static int get_rx_bufs(struct vhost_virtqueue *vq,
+                       struct vring_used_elem *heads,
+                       int datalen,
+                       unsigned *iovcount,
+                       struct vhost_log *log,
+                       unsigned *log_num)
+{
+        unsigned int out, in;
+        int seg = 0;
+        int headcount = 0;
+        unsigned d;
+        int r, nlogs = 0;
+
+        while (datalen > 0) {
+                if (unlikely(headcount >= VHOST_NET_MAX_SG)) {
+                        r = -ENOBUFS;
+                        goto err;
+                }
+                d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg,
+                                      ARRAY_SIZE(vq->iov) - seg, &out,
+                                      &in, log, log_num);
+                if (d == vq->num) {
+                        r = 0;
+                        goto err;
+                }
+                if (unlikely(out || in <= 0)) {
+                        vq_err(vq, "unexpected descriptor format for RX: "
+                                "out %d, in %d\n", out, in);
+                        r = -EINVAL;
+                        goto err;
+                }
+                if (unlikely(log)) {
+                        nlogs += *log_num;
+                        log += *log_num;
+                }
+                heads[headcount].id = d;
+                heads[headcount].len = iov_length(vq->iov + seg, in);
+                datalen -= heads[headcount].len;
+                ++headcount;
+                seg += in;
+        }
+        heads[headcount - 1].len += datalen;
+        *iovcount = seg;
+        if (unlikely(log))
+                *log_num = nlogs;
+        return headcount;
+err:
+        vhost_discard_vq_desc(vq, headcount);
+        return r;
+}
+
 /* 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)
+static void handle_rx_big(struct vhost_net *net)
 {
         struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
         unsigned out, in, log, s;
@@ -223,7 +312,7 @@ static void handle_rx(struct vhost_net *net)
         use_mm(net->dev.mm);
         mutex_lock(&vq->mutex);
         vhost_disable_notify(vq);
-        hdr_size = vq->hdr_size;
+        hdr_size = vq->vhost_hlen;
 
         vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
                 vq->log : NULL;
@@ -270,14 +359,14 @@ static void handle_rx(struct vhost_net *net)
                                          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_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);
+                        vhost_discard_vq_desc(vq, 1);
                         continue;
                 }
                 len = err;
@@ -302,54 +391,175 @@ static void handle_rx(struct vhost_net *net)
         unuse_mm(net->dev.mm);
 }
 
-static void handle_tx_kick(struct work_struct *work)
+/* 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;
-        struct vhost_net *net;
-        vq = container_of(work, struct vhost_virtqueue, poll.work);
-        net = container_of(vq->dev, struct vhost_net, dev);
+        struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
+        unsigned uninitialized_var(in), log;
+        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_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;
+        struct socket *sock = rcu_dereference(vq->private_data);
+        if (!sock || skb_queue_empty(&sock->sk->sk_receive_queue))
+                return;
+
+        use_mm(net->dev.mm);
+        mutex_lock(&vq->mutex);
+        vhost_disable_notify(vq);
+        vhost_hlen = vq->vhost_hlen;
+        sock_hlen = vq->sock_hlen;
+
+        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,
+                                        &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 (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 (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);
+                msg.msg_iovlen = in;
+                err = sock->ops->recvmsg(NULL, sock, &msg,
+                                         sock_len, MSG_DONTWAIT | MSG_TRUNC);
+                /* 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. */
+                if (unlikely(err != sock_len)) {
+                        pr_debug("Discarded rx packet: "
+                                 " len %d, expected %zd\n", err, sock_len);
+                        vhost_discard_vq_desc(vq, headcount);
+                        continue;
+                }
+                if (unlikely(vhost_hlen) &&
+                    memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0,
+                                      vhost_hlen)) {
+                        vq_err(vq, "Unable to write vnet_hdr at addr %p\n",
+                               vq->iov->iov_base);
+                        break;
+                }
+                /* TODO: Should check and handle checksum. */
+                if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF) &&
+                    memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount,
+                                      offsetof(typeof(hdr), num_buffers),
+                                      sizeof hdr.num_buffers)) {
+                        vq_err(vq, "Failed num_buffers write");
+                        vhost_discard_vq_desc(vq, headcount);
+                        break;
+                }
+                vhost_add_used_and_signal_n(&net->dev, vq, vq->heads,
+                                            headcount);
+                if (unlikely(vq_log))
+                        vhost_log_write(vq, vq_log, log, vhost_len);
+                total_len += vhost_len;
+                if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
+                        vhost_poll_queue(&vq->poll);
+                        break;
+                }
+        }
+
+        mutex_unlock(&vq->mutex);
+        unuse_mm(net->dev.mm);
+}
+
+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)
+{
+        struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+                                                  poll.work);
+        struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
+
         handle_tx(net);
 }
 
-static void handle_rx_kick(struct work_struct *work)
+static void handle_rx_kick(struct vhost_work *work)
 {
-        struct vhost_virtqueue *vq;
-        struct vhost_net *net;
-        vq = container_of(work, struct vhost_virtqueue, poll.work);
-        net = container_of(vq->dev, struct vhost_net, dev);
+        struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+                                                  poll.work);
+        struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
+
         handle_rx(net);
 }
 
-static void handle_tx_net(struct work_struct *work)
+static void handle_tx_net(struct vhost_work *work)
 {
-        struct vhost_net *net;
-        net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_TX].work);
+        struct vhost_net *net = container_of(work, struct vhost_net,
+                                             poll[VHOST_NET_VQ_TX].work);
         handle_tx(net);
 }
 
-static void handle_rx_net(struct work_struct *work)
+static void handle_rx_net(struct vhost_work *work)
 {
-        struct vhost_net *net;
-        net = container_of(work, struct vhost_net, poll[VHOST_NET_VQ_RX].work);
+        struct vhost_net *net = container_of(work, struct vhost_net,
+                                             poll[VHOST_NET_VQ_RX].work);
         handle_rx(net);
 }
 
 static int vhost_net_open(struct inode *inode, struct file *f)
 {
         struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
+        struct vhost_dev *dev;
         int r;
+
         if (!n)
                 return -ENOMEM;
+
+        dev = &n->dev;
         n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;
         n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;
-        r = vhost_dev_init(&n->dev, n->vqs, VHOST_NET_VQ_MAX);
+        r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX);
         if (r < 0) {
                 kfree(n);
                 return r;
         }
 
-        vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT);
-        vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN);
+        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;
 
         f->private_data = n;
@@ -573,9 +783,21 @@ done:
 
 static int vhost_net_set_features(struct vhost_net *n, u64 features)
 {
-        size_t hdr_size = features & (1 << VHOST_NET_F_VIRTIO_NET_HDR) ?
-                sizeof(struct virtio_net_hdr) : 0;
+        size_t vhost_hlen, sock_hlen, hdr_len;
         int i;
+
+        hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ?
+                        sizeof(struct virtio_net_hdr_mrg_rxbuf) :
+                        sizeof(struct virtio_net_hdr);
+        if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
+                /* vhost provides vnet_hdr */
+                vhost_hlen = hdr_len;
+                sock_hlen = 0;
+        } else {
+                /* socket provides vnet_hdr */
+                vhost_hlen = 0;
+                sock_hlen = hdr_len;
+        }
         mutex_lock(&n->dev.mutex);
         if ((features & (1 << VHOST_F_LOG_ALL)) &&
             !vhost_log_access_ok(&n->dev)) {
@@ -586,7 +808,8 @@ static int vhost_net_set_features(struct vhost_net *n, u64 features)
         smp_wmb();
         for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
                 mutex_lock(&n->vqs[i].mutex);
-                n->vqs[i].hdr_size = hdr_size;
+                n->vqs[i].vhost_hlen = vhost_hlen;
+                n->vqs[i].sock_hlen = sock_hlen;
                 mutex_unlock(&n->vqs[i].mutex);
         }
         vhost_net_flush(n);
@@ -656,25 +879,13 @@ static struct miscdevice vhost_net_misc = {
 
 static int vhost_net_init(void)
 {
-        int r = vhost_init();
-        if (r)
-                goto err_init;
-        r = misc_register(&vhost_net_misc);
-        if (r)
-                goto err_reg;
-        return 0;
-err_reg:
-        vhost_cleanup();
-err_init:
-        return r;
-
+        return misc_register(&vhost_net_misc);
 }
 module_init(vhost_net_init);
 
 static void vhost_net_exit(void)
 {
         misc_deregister(&vhost_net_misc);
-        vhost_cleanup();
 }
 module_exit(vhost_net_exit);
 
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 248ed2db0711..e05557d52999 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -17,12 +17,13 @@
 #include <linux/mm.h>
 #include <linux/miscdevice.h>
 #include <linux/mutex.h>
-#include <linux/workqueue.h>
 #include <linux/rcupdate.h>
 #include <linux/poll.h>
 #include <linux/file.h>
 #include <linux/highmem.h>
 #include <linux/slab.h>
+#include <linux/kthread.h>
+#include <linux/cgroup.h>
 
 #include <linux/net.h>
 #include <linux/if_packet.h>
@@ -37,8 +38,6 @@ enum {
         VHOST_MEMORY_F_LOG = 0x1,
 };
 
-static struct workqueue_struct *vhost_workqueue;
-
 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
                             poll_table *pt)
 {
@@ -52,23 +51,31 @@ static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
 static int vhost_poll_wakeup(wait_queue_t *wait, unsigned mode, int sync,
                              void *key)
 {
-        struct vhost_poll *poll;
-        poll = container_of(wait, struct vhost_poll, wait);
+        struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
+
         if (!((unsigned long)key & poll->mask))
                 return 0;
 
-        queue_work(vhost_workqueue, &poll->work);
+        vhost_poll_queue(poll);
         return 0;
 }
 
 /* Init poll structure */
-void vhost_poll_init(struct vhost_poll *poll, work_func_t func,
-                     unsigned long mask)
+void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
+                     unsigned long mask, struct vhost_dev *dev)
 {
-        INIT_WORK(&poll->work, func);
+        struct vhost_work *work = &poll->work;
+
         init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
         init_poll_funcptr(&poll->table, vhost_poll_func);
         poll->mask = mask;
+        poll->dev = dev;
+
+        INIT_LIST_HEAD(&work->node);
+        work->fn = fn;
+        init_waitqueue_head(&work->done);
+        work->flushing = 0;
+        work->queue_seq = work->done_seq = 0;
 }
 
 /* Start polling a file. We add ourselves to file's wait queue. The caller must
@@ -92,12 +99,40 @@ void vhost_poll_stop(struct vhost_poll *poll)
  * locks that are also used by the callback. */
 void vhost_poll_flush(struct vhost_poll *poll)
 {
-        flush_work(&poll->work);
+        struct vhost_work *work = &poll->work;
+        unsigned seq;
+        int left;
+        int flushing;
+
+        spin_lock_irq(&poll->dev->work_lock);
+        seq = work->queue_seq;
+        work->flushing++;
+        spin_unlock_irq(&poll->dev->work_lock);
+        wait_event(work->done, ({
+                   spin_lock_irq(&poll->dev->work_lock);
+                   left = seq - work->done_seq <= 0;
+                   spin_unlock_irq(&poll->dev->work_lock);
+                   left;
+        }));
+        spin_lock_irq(&poll->dev->work_lock);
+        flushing = --work->flushing;
+        spin_unlock_irq(&poll->dev->work_lock);
+        BUG_ON(flushing < 0);
 }
 
 void vhost_poll_queue(struct vhost_poll *poll)
 {
-        queue_work(vhost_workqueue, &poll->work);
+        struct vhost_dev *dev = poll->dev;
+        struct vhost_work *work = &poll->work;
+        unsigned long flags;
+
+        spin_lock_irqsave(&dev->work_lock, flags);
+        if (list_empty(&work->node)) {
+                list_add_tail(&work->node, &dev->work_list);
+                work->queue_seq++;
+                wake_up_process(dev->worker);
+        }
+        spin_unlock_irqrestore(&dev->work_lock, flags);
 }
 
 static void vhost_vq_reset(struct vhost_dev *dev,
@@ -114,7 +149,8 @@ static void vhost_vq_reset(struct vhost_dev *dev,
         vq->used_flags = 0;
         vq->log_used = false;
         vq->log_addr = -1ull;
-        vq->hdr_size = 0;
+        vq->vhost_hlen = 0;
+        vq->sock_hlen = 0;
         vq->private_data = NULL;
         vq->log_base = NULL;
         vq->error_ctx = NULL;
@@ -125,10 +161,51 @@ static void vhost_vq_reset(struct vhost_dev *dev,
         vq->log_ctx = NULL;
 }
 
+static int vhost_worker(void *data)
+{
+        struct vhost_dev *dev = data;
+        struct vhost_work *work = NULL;
+        unsigned uninitialized_var(seq);
+
+        for (;;) {
+                /* mb paired w/ kthread_stop */
+                set_current_state(TASK_INTERRUPTIBLE);
+
+                spin_lock_irq(&dev->work_lock);
+                if (work) {
+                        work->done_seq = seq;
+                        if (work->flushing)
+                                wake_up_all(&work->done);
+                }
+
+                if (kthread_should_stop()) {
+                        spin_unlock_irq(&dev->work_lock);
+                        __set_current_state(TASK_RUNNING);
+                        return 0;
+                }
+                if (!list_empty(&dev->work_list)) {
+                        work = list_first_entry(&dev->work_list,
+                                                struct vhost_work, node);
+                        list_del_init(&work->node);
+                        seq = work->queue_seq;
+                } else
+                        work = NULL;
+                spin_unlock_irq(&dev->work_lock);
+
+                if (work) {
+                        __set_current_state(TASK_RUNNING);
+                        work->fn(work);
+                } else
+                        schedule();
+
+        }
+}
+
 long vhost_dev_init(struct vhost_dev *dev,
                     struct vhost_virtqueue *vqs, int nvqs)
 {
         int i;
+
         dev->vqs = vqs;
         dev->nvqs = nvqs;
         mutex_init(&dev->mutex);
@@ -136,6 +213,9 @@ long vhost_dev_init(struct vhost_dev *dev,
         dev->log_file = NULL;
         dev->memory = NULL;
         dev->mm = NULL;
+        spin_lock_init(&dev->work_lock);
+        INIT_LIST_HEAD(&dev->work_list);
+        dev->worker = NULL;
 
         for (i = 0; i < dev->nvqs; ++i) {
                 dev->vqs[i].dev = dev;
@@ -143,9 +223,9 @@ long vhost_dev_init(struct vhost_dev *dev,
                 vhost_vq_reset(dev, dev->vqs + i);
                 if (dev->vqs[i].handle_kick)
                         vhost_poll_init(&dev->vqs[i].poll,
-                                        dev->vqs[i].handle_kick,
-                                        POLLIN);
+                                        dev->vqs[i].handle_kick, POLLIN, dev);
         }
+
         return 0;
 }
 
@@ -159,12 +239,36 @@ long vhost_dev_check_owner(struct vhost_dev *dev)
 /* Caller should have device mutex */
 static long vhost_dev_set_owner(struct vhost_dev *dev)
 {
+        struct task_struct *worker;
+        int err;
         /* Is there an owner already? */
-        if (dev->mm)
-                return -EBUSY;
+        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);
+        if (IS_ERR(worker)) {
+                err = PTR_ERR(worker);
+                goto err_worker;
+        }
+
+        dev->worker = worker;
+        err = cgroup_attach_task_current_cg(worker);
+        if (err)
+                goto err_cgroup;
+        wake_up_process(worker);        /* avoid contributing to loadavg */
+
         return 0;
+err_cgroup:
+        kthread_stop(worker);
+err_worker:
+        if (dev->mm)
+                mmput(dev->mm);
+        dev->mm = NULL;
+err_mm:
+        return err;
 }
 
 /* Caller should have device mutex */
@@ -217,6 +321,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
         if (dev->mm)
                 mmput(dev->mm);
         dev->mm = NULL;
+
+        WARN_ON(!list_empty(&dev->work_list));
+        kthread_stop(dev->worker);
 }
 
 static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
@@ -995,9 +1102,9 @@ int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq,
 }
 
 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
-void vhost_discard_vq_desc(struct vhost_virtqueue *vq)
+void vhost_discard_vq_desc(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
@@ -1042,6 +1149,67 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
         return 0;
 }
 
+static int __vhost_add_used_n(struct vhost_virtqueue *vq,
+                            struct vring_used_elem *heads,
+                            unsigned count)
+{
+        struct vring_used_elem __user *used;
+        int start;
+
+        start = vq->last_used_idx % vq->num;
+        used = vq->used->ring + start;
+        if (copy_to_user(used, heads, count * sizeof *used)) {
+                vq_err(vq, "Failed to write used");
+                return -EFAULT;
+        }
+        if (unlikely(vq->log_used)) {
+                /* Make sure data is seen before log. */
+                smp_wmb();
+                /* Log used ring entry write. */
+                log_write(vq->log_base,
+                          vq->log_addr +
+                           ((void __user *)used - (void __user *)vq->used),
+                          count * sizeof *used);
+        }
+        vq->last_used_idx += count;
+        return 0;
+}
+
+/* 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_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
+                     unsigned count)
+{
+        int start, n, r;
+
+        start = vq->last_used_idx % vq->num;
+        n = vq->num - start;
+        if (n < count) {
+                r = __vhost_add_used_n(vq, heads, n);
+                if (r < 0)
+                        return r;
+                heads += n;
+                count -= n;
+        }
+        r = __vhost_add_used_n(vq, heads, count);
+
+        /* Make sure buffer is written before we update index. */
+        smp_wmb();
+        if (put_user(vq->last_used_idx, &vq->used->idx)) {
+                vq_err(vq, "Failed to increment used idx");
+                return -EFAULT;
+        }
+        if (unlikely(vq->log_used)) {
+                /* Log used index update. */
+                log_write(vq->log_base,
+                          vq->log_addr + offsetof(struct vring_used, idx),
+                          sizeof vq->used->idx);
+                if (vq->log_ctx)
+                        eventfd_signal(vq->log_ctx, 1);
+        }
+        return r;
+}
+
 /* This actually signals the guest, using eventfd. */
 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
 {
@@ -1076,6 +1244,15 @@ void vhost_add_used_and_signal(struct vhost_dev *dev,
         vhost_signal(dev, vq);
 }
 
+/* multi-buffer version of vhost_add_used_and_signal */
+void vhost_add_used_and_signal_n(struct vhost_dev *dev,
+                                 struct vhost_virtqueue *vq,
+                                 struct vring_used_elem *heads, unsigned count)
+{
+        vhost_add_used_n(vq, heads, count);
+        vhost_signal(dev, vq);
+}
+
 /* OK, now we need to know about added descriptors. */
 bool vhost_enable_notify(struct vhost_virtqueue *vq)
 {
@@ -1100,7 +1277,7 @@ bool vhost_enable_notify(struct vhost_virtqueue *vq)
                 return false;
         }
 
-        return avail_idx != vq->last_avail_idx;
+        return avail_idx != vq->avail_idx;
 }
 
 /* We don't need to be notified again. */
@@ -1115,16 +1292,3 @@ void vhost_disable_notify(struct vhost_virtqueue *vq)
                 vq_err(vq, "Failed to enable notification at %p: %d\n",
                        &vq->used->flags, r);
 }
-
-int vhost_init(void)
-{
-        vhost_workqueue = create_singlethread_workqueue("vhost");
-        if (!vhost_workqueue)
-                return -ENOMEM;
-        return 0;
-}
-
-void vhost_cleanup(void)
-{
-        destroy_workqueue(vhost_workqueue);
-}
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 11ee13dba0f7..afd77295971c 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -5,13 +5,13 @@
 #include <linux/vhost.h>
 #include <linux/mm.h>
 #include <linux/mutex.h>
-#include <linux/workqueue.h>
 #include <linux/poll.h>
 #include <linux/file.h>
 #include <linux/skbuff.h>
 #include <linux/uio.h>
 #include <linux/virtio_config.h>
 #include <linux/virtio_ring.h>
+#include <asm/atomic.h>
 
 struct vhost_device;
 
@@ -20,19 +20,31 @@ enum {
         VHOST_NET_MAX_SG = MAX_SKB_FRAGS + 2,
 };
 
+struct vhost_work;
+typedef void (*vhost_work_fn_t)(struct vhost_work *work);
+
+struct vhost_work {
+        struct list_head          node;
+        vhost_work_fn_t           fn;
+        wait_queue_head_t         done;
+        int                       flushing;
+        unsigned                  queue_seq;
+        unsigned                  done_seq;
+};
+
 /* Poll a file (eventfd or socket) */
 /* Note: there's nothing vhost specific about this structure. */
 struct vhost_poll {
         poll_table                table;
         wait_queue_head_t        *wqh;
         wait_queue_t              wait;
-        /* struct which will handle all actual work. */
-        struct work_struct        work;
+        struct vhost_work         work;
         unsigned long             mask;
+        struct vhost_dev         *dev;
 };
 
-void vhost_poll_init(struct vhost_poll *poll, work_func_t func,
-                     unsigned long mask);
+void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
+                     unsigned long mask, struct vhost_dev *dev);
 void vhost_poll_start(struct vhost_poll *poll, struct file *file);
 void vhost_poll_stop(struct vhost_poll *poll);
 void vhost_poll_flush(struct vhost_poll *poll);
@@ -63,7 +75,7 @@ struct vhost_virtqueue {
         struct vhost_poll poll;
 
         /* The routine to call when the Guest pings us, or timeout. */
-        work_func_t handle_kick;
+        vhost_work_fn_t handle_kick;
 
         /* Last available index we saw. */
         u16 last_avail_idx;
@@ -84,13 +96,15 @@ struct vhost_virtqueue {
         struct iovec indirect[VHOST_NET_MAX_SG];
         struct iovec iov[VHOST_NET_MAX_SG];
         struct iovec hdr[VHOST_NET_MAX_SG];
-        size_t hdr_size;
+        size_t vhost_hlen;
+        size_t sock_hlen;
+        struct vring_used_elem heads[VHOST_NET_MAX_SG];
         /* We use a kind of RCU to access private pointer.
-         * All readers access it from workqueue, which makes it possible to
-         * flush the workqueue instead of synchronize_rcu. Therefore readers do
+         * All readers access it from worker, which makes it possible to
+         * flush the vhost_work instead of synchronize_rcu. Therefore readers do
          * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
-         * work item execution acts instead of rcu_read_lock() and the end of
-         * work item execution acts instead of rcu_read_lock().
+         * vhost_work execution acts instead of rcu_read_lock() and the end of
+         * vhost_work execution acts instead of rcu_read_lock().
          * Writers use virtqueue mutex. */
         void *private_data;
         /* Log write descriptors */
@@ -110,6 +124,9 @@ struct vhost_dev {
         int nvqs;
         struct file *log_file;
         struct eventfd_ctx *log_ctx;
+        spinlock_t work_lock;
+        struct list_head work_list;
+        struct task_struct *worker;
 };
 
 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
@@ -124,21 +141,22 @@ 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);
-void vhost_discard_vq_desc(struct vhost_virtqueue *);
+void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 
 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_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
+                     unsigned count);
 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
-                               unsigned int head, int len);
+                               unsigned int id, int len);
+void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
+                               struct vring_used_elem *heads, unsigned count);
+void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 void vhost_disable_notify(struct vhost_virtqueue *);
 bool vhost_enable_notify(struct vhost_virtqueue *);
 
 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
                     unsigned int log_num, u64 len);
 
-int vhost_init(void);
-void vhost_cleanup(void);
-
 #define vq_err(vq, fmt, ...) do {                                  \
                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
                 if ((vq)->error_ctx)                               \
@@ -149,7 +167,8 @@ enum {
         VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) |
                          (1 << VIRTIO_RING_F_INDIRECT_DESC) |
                          (1 << VHOST_F_LOG_ALL) |
-                         (1 << VHOST_NET_F_VIRTIO_NET_HDR),
+                         (1 << VHOST_NET_F_VIRTIO_NET_HDR) |
+                         (1 << VIRTIO_NET_F_MRG_RXBUF),
 };
 
 static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 0c621604baa1..e0aa067d1b11 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -570,6 +570,7 @@ struct task_struct *cgroup_iter_next(struct cgroup *cgrp,
 void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it);
 int cgroup_scan_tasks(struct cgroup_scanner *scan);
 int cgroup_attach_task(struct cgroup *, struct task_struct *);
+int cgroup_attach_task_current_cg(struct task_struct *);
 
 /*
  * CSS ID is ID for cgroup_subsys_state structs under subsys. This only works
@@ -626,6 +627,12 @@ static inline int cgroupstats_build(struct cgroupstats *stats,
         return -EINVAL;
 }
 
+/* No cgroups - nothing to do */
+static inline int cgroup_attach_task_current_cg(struct task_struct *t)
+{
+        return 0;
+}
+
 #endif /* !CONFIG_CGROUPS */
 
 #endif /* _LINUX_CGROUP_H */
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 422cb19f156e..37642ad9cca8 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1788,6 +1788,29 @@ out:
         return retval;
 }
 
+/**
+ * cgroup_attach_task_current_cg - attach task 'tsk' to current task's cgroup
+ * @tsk: the task to be attached
+ */
+int cgroup_attach_task_current_cg(struct task_struct *tsk)
+{
+        struct cgroupfs_root *root;
+        struct cgroup *cur_cg;
+        int retval = 0;
+
+        cgroup_lock();
+        for_each_active_root(root) {
+                cur_cg = task_cgroup_from_root(current, root);
+                retval = cgroup_attach_task(cur_cg, tsk);
+                if (retval)
+                        break;
+        }
+        cgroup_unlock();
+
+        return retval;
+}
+EXPORT_SYMBOL_GPL(cgroup_attach_task_current_cg);
+
 /*
  * Attach task with pid 'pid' to cgroup 'cgrp'. Call with cgroup_mutex
  * held. May take task_lock of task