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-rw-r--r--net/9p/trans_xen.c87
1 files changed, 85 insertions, 2 deletions
diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c
index fe3d172391c4..28f30f49d5dd 100644
--- a/net/9p/trans_xen.c
+++ b/net/9p/trans_xen.c
@@ -85,22 +85,105 @@ struct xen_9pfs_front_priv {
static LIST_HEAD(xen_9pfs_devs);
static DEFINE_RWLOCK(xen_9pfs_lock);
+/* We don't currently allow canceling of requests */
static int p9_xen_cancel(struct p9_client *client, struct p9_req_t *req)
{
- return 0;
+ return 1;
}
static int p9_xen_create(struct p9_client *client, const char *addr, char *args)
{
- return 0;
+ struct xen_9pfs_front_priv *priv;
+
+ read_lock(&xen_9pfs_lock);
+ list_for_each_entry(priv, &xen_9pfs_devs, list) {
+ if (!strcmp(priv->tag, addr)) {
+ priv->client = client;
+ read_unlock(&xen_9pfs_lock);
+ return 0;
+ }
+ }
+ read_unlock(&xen_9pfs_lock);
+ return -EINVAL;
}
static void p9_xen_close(struct p9_client *client)
{
+ struct xen_9pfs_front_priv *priv;
+
+ read_lock(&xen_9pfs_lock);
+ list_for_each_entry(priv, &xen_9pfs_devs, list) {
+ if (priv->client == client) {
+ priv->client = NULL;
+ read_unlock(&xen_9pfs_lock);
+ return;
+ }
+ }
+ read_unlock(&xen_9pfs_lock);
+}
+
+static bool p9_xen_write_todo(struct xen_9pfs_dataring *ring, RING_IDX size)
+{
+ RING_IDX cons, prod;
+
+ cons = ring->intf->out_cons;
+ prod = ring->intf->out_prod;
+ virt_mb();
+
+ return XEN_9PFS_RING_SIZE -
+ xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) >= size;
}
static int p9_xen_request(struct p9_client *client, struct p9_req_t *p9_req)
{
+ struct xen_9pfs_front_priv *priv = NULL;
+ RING_IDX cons, prod, masked_cons, masked_prod;
+ unsigned long flags;
+ u32 size = p9_req->tc->size;
+ struct xen_9pfs_dataring *ring;
+ int num;
+
+ read_lock(&xen_9pfs_lock);
+ list_for_each_entry(priv, &xen_9pfs_devs, list) {
+ if (priv->client == client)
+ break;
+ }
+ read_unlock(&xen_9pfs_lock);
+ if (!priv || priv->client != client)
+ return -EINVAL;
+
+ num = p9_req->tc->tag % priv->num_rings;
+ ring = &priv->rings[num];
+
+again:
+ while (wait_event_interruptible(ring->wq,
+ p9_xen_write_todo(ring, size)) != 0)
+ ;
+
+ spin_lock_irqsave(&ring->lock, flags);
+ cons = ring->intf->out_cons;
+ prod = ring->intf->out_prod;
+ virt_mb();
+
+ if (XEN_9PFS_RING_SIZE - xen_9pfs_queued(prod, cons,
+ XEN_9PFS_RING_SIZE) < size) {
+ spin_unlock_irqrestore(&ring->lock, flags);
+ goto again;
+ }
+
+ masked_prod = xen_9pfs_mask(prod, XEN_9PFS_RING_SIZE);
+ masked_cons = xen_9pfs_mask(cons, XEN_9PFS_RING_SIZE);
+
+ xen_9pfs_write_packet(ring->data.out, p9_req->tc->sdata, size,
+ &masked_prod, masked_cons, XEN_9PFS_RING_SIZE);
+
+ p9_req->status = REQ_STATUS_SENT;
+ virt_wmb(); /* write ring before updating pointer */
+ prod += size;
+ ring->intf->out_prod = prod;
+ spin_unlock_irqrestore(&ring->lock, flags);
+ notify_remote_via_irq(ring->irq);
+
return 0;
}