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vhost: move -net specific code out
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Zerocopy handling code is vhost-net specific.
Move it from vhost.c/vhost.h out to net.c

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Michael S. Tsirkin authored and David S. Miller committed Nov 3, 2012
1 parent c4fcb58 commit b211616
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Showing 4 changed files with 56 additions and 64 deletions.
45 changes: 45 additions & 0 deletions drivers/vhost/net.c
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Original file line number Diff line number Diff line change
Expand Up @@ -126,6 +126,42 @@ static void tx_poll_start(struct vhost_net *net, struct socket *sock)
net->tx_poll_state = VHOST_NET_POLL_STARTED;
}

/* In case of DMA done not in order in lower device driver for some reason.
* upend_idx is used to track end of used idx, done_idx is used to track head
* of used idx. Once lower device DMA done contiguously, we will signal KVM
* guest used idx.
*/
int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq)
{
int i;
int j = 0;

for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
vhost_add_used_and_signal(vq->dev, vq,
vq->heads[i].id, 0);
++j;
} else
break;
}
if (j)
vq->done_idx = i;
return j;
}

static void vhost_zerocopy_callback(struct ubuf_info *ubuf, int status)
{
struct vhost_ubuf_ref *ubufs = ubuf->ctx;
struct vhost_virtqueue *vq = ubufs->vq;

vhost_poll_queue(&vq->poll);
/* set len to mark this desc buffers done DMA */
vq->heads[ubuf->desc].len = status ?
VHOST_DMA_FAILED_LEN : VHOST_DMA_DONE_LEN;
vhost_ubuf_put(ubufs);
}

/* 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)
Expand Down Expand Up @@ -594,9 +630,18 @@ static int vhost_net_release(struct inode *inode, struct file *f)
struct vhost_net *n = f->private_data;
struct socket *tx_sock;
struct socket *rx_sock;
int i;

vhost_net_stop(n, &tx_sock, &rx_sock);
vhost_net_flush(n);
vhost_dev_stop(&n->dev);
for (i = 0; i < n->dev.nvqs; ++i) {
/* Wait for all lower device DMAs done. */
if (n->dev.vqs[i].ubufs)
vhost_ubuf_put_and_wait(n->dev.vqs[i].ubufs);

vhost_zerocopy_signal_used(n, &n->dev.vqs[i]);
}
vhost_dev_cleanup(&n->dev, false);
if (tx_sock)
fput(tx_sock->file);
Expand Down
1 change: 1 addition & 0 deletions drivers/vhost/tcm_vhost.c
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Original file line number Diff line number Diff line change
Expand Up @@ -895,6 +895,7 @@ static int vhost_scsi_release(struct inode *inode, struct file *f)
vhost_scsi_clear_endpoint(s, &backend);
}

vhost_dev_stop(&s->dev);
vhost_dev_cleanup(&s->dev, false);
kfree(s);
return 0;
Expand Down
53 changes: 7 additions & 46 deletions drivers/vhost/vhost.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,10 +26,6 @@
#include <linux/kthread.h>
#include <linux/cgroup.h>

#include <linux/net.h>
#include <linux/if_packet.h>
#include <linux/if_arp.h>

#include "vhost.h"

enum {
Expand Down Expand Up @@ -414,28 +410,16 @@ long vhost_dev_reset_owner(struct vhost_dev *dev)
return 0;
}

/* In case of DMA done not in order in lower device driver for some reason.
* upend_idx is used to track end of used idx, done_idx is used to track head
* of used idx. Once lower device DMA done contiguously, we will signal KVM
* guest used idx.
*/
int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq)
void vhost_dev_stop(struct vhost_dev *dev)
{
int i;
int j = 0;

for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
vhost_add_used_and_signal(vq->dev, vq,
vq->heads[i].id, 0);
++j;
} else
break;

for (i = 0; i < dev->nvqs; ++i) {
if (dev->vqs[i].kick && dev->vqs[i].handle_kick) {
vhost_poll_stop(&dev->vqs[i].poll);
vhost_poll_flush(&dev->vqs[i].poll);
}
}
if (j)
vq->done_idx = i;
return j;
}

/* Caller should have device mutex if and only if locked is set */
Expand All @@ -444,17 +428,6 @@ void vhost_dev_cleanup(struct vhost_dev *dev, bool locked)
int i;

for (i = 0; i < dev->nvqs; ++i) {
if (dev->vqs[i].kick && dev->vqs[i].handle_kick) {
vhost_poll_stop(&dev->vqs[i].poll);
vhost_poll_flush(&dev->vqs[i].poll);
}
/* Wait for all lower device DMAs done. */
if (dev->vqs[i].ubufs)
vhost_ubuf_put_and_wait(dev->vqs[i].ubufs);

/* Signal guest as appropriate. */
vhost_zerocopy_signal_used(&dev->vqs[i]);

if (dev->vqs[i].error_ctx)
eventfd_ctx_put(dev->vqs[i].error_ctx);
if (dev->vqs[i].error)
Expand Down Expand Up @@ -1599,15 +1572,3 @@ void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs)
wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount));
kfree(ubufs);
}

void vhost_zerocopy_callback(struct ubuf_info *ubuf, int status)
{
struct vhost_ubuf_ref *ubufs = ubuf->ctx;
struct vhost_virtqueue *vq = ubufs->vq;

vhost_poll_queue(&vq->poll);
/* set len to mark this desc buffers done DMA */
vq->heads[ubuf->desc].len = status ?
VHOST_DMA_FAILED_LEN : VHOST_DMA_DONE_LEN;
kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
}
21 changes: 3 additions & 18 deletions drivers/vhost/vhost.h
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Original file line number Diff line number Diff line change
Expand Up @@ -7,27 +7,11 @@
#include <linux/mutex.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 <linux/atomic.h>

/*
* For transmit, used buffer len is unused; we override it to track buffer
* status internally; used for zerocopy tx only.
*/
/* Lower device DMA failed */
#define VHOST_DMA_FAILED_LEN 3
/* Lower device DMA done */
#define VHOST_DMA_DONE_LEN 2
/* Lower device DMA in progress */
#define VHOST_DMA_IN_PROGRESS 1
/* Buffer unused */
#define VHOST_DMA_CLEAR_LEN 0

#define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN)

struct vhost_device;

struct vhost_work;
Expand Down Expand Up @@ -80,6 +64,8 @@ struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *, bool zcopy);
void vhost_ubuf_put(struct vhost_ubuf_ref *);
void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *);

struct ubuf_info;

/* The virtqueue structure describes a queue attached to a device. */
struct vhost_virtqueue {
struct vhost_dev *dev;
Expand Down Expand Up @@ -177,6 +163,7 @@ long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
long vhost_dev_check_owner(struct vhost_dev *);
long vhost_dev_reset_owner(struct vhost_dev *);
void vhost_dev_cleanup(struct vhost_dev *, bool locked);
void vhost_dev_stop(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 *);
Expand All @@ -201,8 +188,6 @@ bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);

int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
unsigned int log_num, u64 len);
void vhost_zerocopy_callback(struct ubuf_info *, bool);
int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq);

#define vq_err(vq, fmt, ...) do { \
pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
Expand Down

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