[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 5/7] xen/9pfs: send requests to the backend
Implement struct p9_trans_module create and close functions by looking at the available Xen 9pfs frontend-backend connections. We don't expect many frontend-backend connections, thus walking a list is OK. Send requests to the backend by copying each request to one of the available rings (each frontend-backend connection comes with multiple rings). Handle the ring and notifications following the 9pfs specification. If there are not enough free bytes on the ring for the request, wait on the wait_queue: the backend will send a notification after consuming more requests. Signed-off-by: Stefano Stabellini <stefano@xxxxxxxxxxx> CC: boris.ostrovsky@xxxxxxxxxx CC: jgross@xxxxxxxx CC: Eric Van Hensbergen <ericvh@xxxxxxxxx> CC: Ron Minnich <rminnich@xxxxxxxxxx> CC: Latchesar Ionkov <lucho@xxxxxxxxxx> CC: v9fs-developer@xxxxxxxxxxxxxxxxxxxxx --- net/9p/trans_xen.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 79 insertions(+), 2 deletions(-) diff --git a/net/9p/trans_xen.c b/net/9p/trans_xen.c index 0e66dbe..0367cbe 100644 --- a/net/9p/trans_xen.c +++ b/net/9p/trans_xen.c @@ -47,22 +47,99 @@ struct xen_9pfs_front_priv { }; static LIST_HEAD(xen_9pfs_devs); +/* 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; + + list_for_each_entry(priv, &xen_9pfs_devs, list) { + if (!strcmp(priv->tag, addr)) { + priv->client = client; + return 0; + } + } + return -EINVAL; } static void p9_xen_close(struct p9_client *client) { + struct xen_9pfs_front_priv *priv; + + list_for_each_entry(priv, &xen_9pfs_devs, list) { + if (priv->client == client) { + priv->client = NULL; + return; + } + } + return; +} + +static int 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(); + + if (XEN_9PFS_RING_SIZE - xen_9pfs_queued(prod, cons, XEN_9PFS_RING_SIZE) >= size) + return 1; + else + return 0; } 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; + uint32_t size = p9_req->tc->size; + struct xen_9pfs_dataring *ring; + int num; + + list_for_each_entry(priv, &xen_9pfs_devs, list) { + if (priv->client == client) + break; + } + if (priv == NULL || 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) != 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->ring.out, + &masked_prod, masked_cons, + XEN_9PFS_RING_SIZE, p9_req->tc->sdata, 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; } -- 1.9.1 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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