unuse_mm(net->dev.mm);
}
-static void handle_tx_kick(struct work_struct *work)
+static void handle_tx_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_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;
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);
#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/net.h>
#include <linux/if_packet.h>
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)
{
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
* 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,
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);
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;
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;
}
/* 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;
+ wake_up_process(worker); /* avoid contributing to loadavg */
+
return 0;
+err_worker:
+ if (dev->mm)
+ mmput(dev->mm);
+ dev->mm = NULL;
+err_mm:
+ return err;
}
/* Caller should have device mutex */
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)
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);
-}
#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;
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);
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;
struct iovec hdr[VHOST_NET_MAX_SG];
size_t hdr_size;
/* 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 */
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);
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) \
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