1 files changed, 141 insertions, 23 deletions

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 176aa030dc5f..8672e0538d59 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -64,8 +64,24 @@ enum {
         VHOST_NET_VQ_MAX = 2,
 };
 
+struct vhost_ubuf_ref {
+        struct kref kref;
+        wait_queue_head_t wait;
+        struct vhost_virtqueue *vq;
+};
+
 struct vhost_net_virtqueue {
         struct vhost_virtqueue vq;
+        /* vhost zerocopy support fields below: */
+        /* last used idx for outstanding DMA zerocopy buffers */
+        int upend_idx;
+        /* first used idx for DMA done zerocopy buffers */
+        int done_idx;
+        /* an array of userspace buffers info */
+        struct ubuf_info *ubuf_info;
+        /* Reference counting for outstanding ubufs.
+         * Protected by vq mutex. Writers must also take device mutex. */
+        struct vhost_ubuf_ref *ubufs;
 };
 
 struct vhost_net {
@@ -82,6 +98,88 @@ struct vhost_net {
         bool tx_flush;
 };
 
+static unsigned vhost_zcopy_mask __read_mostly;
+
+void vhost_enable_zcopy(int vq)
+{
+        vhost_zcopy_mask |= 0x1 << vq;
+}
+
+static void vhost_zerocopy_done_signal(struct kref *kref)
+{
+        struct vhost_ubuf_ref *ubufs = container_of(kref, struct vhost_ubuf_ref,
+                                                    kref);
+        wake_up(&ubufs->wait);
+}
+
+struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *vq,
+                                        bool zcopy)
+{
+        struct vhost_ubuf_ref *ubufs;
+        /* No zero copy backend? Nothing to count. */
+        if (!zcopy)
+                return NULL;
+        ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL);
+        if (!ubufs)
+                return ERR_PTR(-ENOMEM);
+        kref_init(&ubufs->kref);
+        init_waitqueue_head(&ubufs->wait);
+        ubufs->vq = vq;
+        return ubufs;
+}
+
+void vhost_ubuf_put(struct vhost_ubuf_ref *ubufs)
+{
+        kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
+}
+
+void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs)
+{
+        kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
+        wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount));
+        kfree(ubufs);
+}
+
+int vhost_net_set_ubuf_info(struct vhost_net *n)
+{
+        bool zcopy;
+        int i;
+
+        for (i = 0; i < n->dev.nvqs; ++i) {
+                zcopy = vhost_zcopy_mask & (0x1 << i);
+                if (!zcopy)
+                        continue;
+                n->vqs[i].ubuf_info = kmalloc(sizeof(*n->vqs[i].ubuf_info) *
+                                              UIO_MAXIOV, GFP_KERNEL);
+                if  (!n->vqs[i].ubuf_info)
+                        goto err;
+        }
+        return 0;
+
+err:
+        while (i--) {
+                zcopy = vhost_zcopy_mask & (0x1 << i);
+                if (!zcopy)
+                        continue;
+                kfree(n->vqs[i].ubuf_info);
+        }
+        return -ENOMEM;
+}
+
+void vhost_net_reset_ubuf_info(struct vhost_net *n)
+{
+        int i;
+
+        for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
+                n->vqs[i].done_idx = 0;
+                n->vqs[i].upend_idx = 0;
+                n->vqs[i].ubufs = NULL;
+                kfree(n->vqs[i].ubuf_info);
+                n->vqs[i].ubuf_info = NULL;
+        }
+
+}
+
 static void vhost_net_tx_packet(struct vhost_net *net)
 {
         ++net->tx_packets;
@@ -157,10 +255,12 @@ static void copy_iovec_hdr(const struct iovec *from, struct iovec *to,
 static int vhost_zerocopy_signal_used(struct vhost_net *net,
                                       struct vhost_virtqueue *vq)
 {
+        struct vhost_net_virtqueue *nvq =
+                container_of(vq, struct vhost_net_virtqueue, vq);
         int i;
         int j = 0;
 
-        for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
+        for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
                 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN)
                         vhost_net_tx_err(net);
                 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
@@ -172,7 +272,7 @@ static int vhost_zerocopy_signal_used(struct vhost_net *net,
                         break;
         }
         if (j)
-                vq->done_idx = i;
+                nvq->done_idx = i;
         return j;
 }
 
@@ -203,6 +303,7 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
 static void handle_tx(struct vhost_net *net)
 {
         struct vhost_virtqueue *vq = &net->vqs[VHOST_NET_VQ_TX].vq;
+        struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
         unsigned out, in, s;
         int head;
         struct msghdr msg = {
@@ -229,7 +330,7 @@ static void handle_tx(struct vhost_net *net)
         vhost_disable_notify(&net->dev, vq);
 
         hdr_size = vq->vhost_hlen;
-        zcopy = vq->ubufs;
+        zcopy = nvq->ubufs;
 
         for (;;) {
                 /* Release DMAs done buffers first */
@@ -250,9 +351,10 @@ static void handle_tx(struct vhost_net *net)
                         /* If more outstanding DMAs, queue the work.
                          * Handle upend_idx wrap around
                          */
-                        num_pends = likely(vq->upend_idx >= vq->done_idx) ?
-                                    (vq->upend_idx - vq->done_idx) :
-                                    (vq->upend_idx + UIO_MAXIOV - vq->done_idx);
+                        num_pends = likely(nvq->upend_idx >= nvq->done_idx) ?
+                                    (nvq->upend_idx - nvq->done_idx) :
+                                    (nvq->upend_idx + UIO_MAXIOV -
+                                     nvq->done_idx);
                         if (unlikely(num_pends > VHOST_MAX_PEND))
                                 break;
                         if (unlikely(vhost_enable_notify(&net->dev, vq))) {
@@ -278,34 +380,34 @@ static void handle_tx(struct vhost_net *net)
                         break;
                 }
                 zcopy_used = zcopy && (len >= VHOST_GOODCOPY_LEN ||
-                                       vq->upend_idx != vq->done_idx);
+                                       nvq->upend_idx != nvq->done_idx);
 
                 /* use msg_control to pass vhost zerocopy ubuf info to skb */
                 if (zcopy_used) {
-                        vq->heads[vq->upend_idx].id = head;
+                        vq->heads[nvq->upend_idx].id = head;
                         if (!vhost_net_tx_select_zcopy(net) ||
                             len < VHOST_GOODCOPY_LEN) {
                                 /* copy don't need to wait for DMA done */
-                                vq->heads[vq->upend_idx].len =
+                                vq->heads[nvq->upend_idx].len =
                                                         VHOST_DMA_DONE_LEN;
                                 msg.msg_control = NULL;
                                 msg.msg_controllen = 0;
                                 ubufs = NULL;
                         } else {
                                 struct ubuf_info *ubuf;
-                                ubuf = vq->ubuf_info + vq->upend_idx;
+                                ubuf = nvq->ubuf_info + nvq->upend_idx;
 
-                                vq->heads[vq->upend_idx].len =
+                                vq->heads[nvq->upend_idx].len =
                                         VHOST_DMA_IN_PROGRESS;
                                 ubuf->callback = vhost_zerocopy_callback;
-                                ubuf->ctx = vq->ubufs;
-                                ubuf->desc = vq->upend_idx;
+                                ubuf->ctx = nvq->ubufs;
+                                ubuf->desc = nvq->upend_idx;
                                 msg.msg_control = ubuf;
                                 msg.msg_controllen = sizeof(ubuf);
-                                ubufs = vq->ubufs;
+                                ubufs = nvq->ubufs;
                                 kref_get(&ubufs->kref);
                         }
-                        vq->upend_idx = (vq->upend_idx + 1) % UIO_MAXIOV;
+                        nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
                 }
                 /* TODO: Check specific error and bomb out unless ENOBUFS? */
                 err = sock->ops->sendmsg(NULL, sock, &msg, len);
@@ -313,8 +415,8 @@ static void handle_tx(struct vhost_net *net)
                         if (zcopy_used) {
                                 if (ubufs)
                                         vhost_ubuf_put(ubufs);
-                                vq->upend_idx = ((unsigned)vq->upend_idx - 1) %
-                                        UIO_MAXIOV;
+                                nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
+                                        % UIO_MAXIOV;
                         }
                         vhost_discard_vq_desc(vq, 1);
                         break;
@@ -564,7 +666,7 @@ static int vhost_net_open(struct inode *inode, struct file *f)
         struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
         struct vhost_dev *dev;
         struct vhost_virtqueue **vqs;
-        int r;
+        int r, i;
 
         if (!n)
                 return -ENOMEM;
@@ -579,6 +681,12 @@ static int vhost_net_open(struct inode *inode, struct file *f)
         vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq;
         n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick;
         n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick;
+        for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
+                n->vqs[i].ubufs = NULL;
+                n->vqs[i].ubuf_info = NULL;
+                n->vqs[i].upend_idx = 0;
+                n->vqs[i].done_idx = 0;
+        }
         r = vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);
         if (r < 0) {
                 kfree(n);
@@ -652,15 +760,15 @@ static void vhost_net_flush(struct vhost_net *n)
 {
         vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
         vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
-        if (n->vqs[VHOST_NET_VQ_TX].vq.ubufs) {
+        if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
                 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
                 n->tx_flush = true;
                 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
                 /* Wait for all lower device DMAs done. */
-                vhost_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].vq.ubufs);
+                vhost_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
                 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
                 n->tx_flush = false;
-                kref_init(&n->vqs[VHOST_NET_VQ_TX].vq.ubufs->kref);
+                kref_init(&n->vqs[VHOST_NET_VQ_TX].ubufs->kref);
                 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
         }
 }
@@ -675,6 +783,7 @@ static int vhost_net_release(struct inode *inode, struct file *f)
         vhost_net_flush(n);
         vhost_dev_stop(&n->dev);
         vhost_dev_cleanup(&n->dev, false);
+        vhost_net_reset_ubuf_info(n);
         if (tx_sock)
                 fput(tx_sock->file);
         if (rx_sock)
@@ -756,6 +865,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
 {
         struct socket *sock, *oldsock;
         struct vhost_virtqueue *vq;
+        struct vhost_net_virtqueue *nvq;
         struct vhost_ubuf_ref *ubufs, *oldubufs = NULL;
         int r;
 
@@ -769,6 +879,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
                 goto err;
         }
         vq = &n->vqs[index].vq;
+        nvq = &n->vqs[index];
         mutex_lock(&vq->mutex);
 
         /* Verify that ring has been setup correctly. */
@@ -801,8 +912,8 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
                 if (r)
                         goto err_used;
 
-                oldubufs = vq->ubufs;
-                vq->ubufs = ubufs;
+                oldubufs = nvq->ubufs;
+                nvq->ubufs = ubufs;
 
                 n->tx_packets = 0;
                 n->tx_zcopy_err = 0;
@@ -853,6 +964,7 @@ static long vhost_net_reset_owner(struct vhost_net *n)
         vhost_net_stop(n, &tx_sock, &rx_sock);
         vhost_net_flush(n);
         err = vhost_dev_reset_owner(&n->dev);
+        vhost_net_reset_ubuf_info(n);
 done:
         mutex_unlock(&n->dev.mutex);
         if (tx_sock)
@@ -928,11 +1040,17 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
                 return vhost_net_reset_owner(n);
         default:
                 mutex_lock(&n->dev.mutex);
+                if (ioctl == VHOST_SET_OWNER) {
+                        r = vhost_net_set_ubuf_info(n);
+                        if (r)
+                                goto out;
+                }
                 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
                 if (r == -ENOIOCTLCMD)
                         r = vhost_vring_ioctl(&n->dev, ioctl, argp);
                 else
                         vhost_net_flush(n);
+out:
                 mutex_unlock(&n->dev.mutex);
                 return r;
         }