diff options
| -rw-r--r-- | net/9p/trans_xen.c | 87 |
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; } |