Merge branch 'vhost-net-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost (4fc6eb7d) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/vhost/net.c

+252 −41

Original line number	Diff line number	Diff line
		@@ -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 @@ static long vhost_net_reset_owner(struct vhost_net *n)

		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);

drivers/vhost/vhost.c

+196 −32

Original line number	Diff line number	Diff line
		@@ -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);
		}

drivers/vhost/vhost.h

+37 −18

Original line number	Diff line number	Diff line
		@@ -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)

include/linux/cgroup.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -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 */

kernel/cgroup.c

+23 −0

Original line number	Diff line number	Diff line
		@@ -1788,6 +1788,29 @@ int cgroup_attach_task(struct cgroup cgrp, struct task_struct tsk)
		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