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xen/9pfs: receive requests from the frontend 

Upon receiving an event channel notification from the frontend, schedule
the bottom half. From the bottom half, read one request from the ring,
create a pdu and call pdu_submit to handle it.

For now, only handle one request per ring at a time.

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
CC: anthony.perard@citrix.com
CC: jgross@suse.com
CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
CC: Greg Kurz <groug@kaod.org>
This commit is contained in:
Stefano Stabellini 2017-03-22 10:16:03 -07:00
parent f23ef34a5d
commit 47b70fb1e4
1 changed files with 50 additions and 0 deletions
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50
hw/9pfs/xen-9p-backend.c
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@ -100,12 +100,62 @@ static int xen_9pfs_init(struct XenDevice *xendev)
return 0;
}
static int xen_9pfs_receive(Xen9pfsRing *ring)
{
P9MsgHeader h;
RING_IDX cons, prod, masked_prod, masked_cons;
V9fsPDU *pdu;
if (ring->inprogress) {
return 0;
}
cons = ring->intf->out_cons;
prod = ring->intf->out_prod;
xen_rmb();
if (xen_9pfs_queued(prod, cons, XEN_FLEX_RING_SIZE(ring->ring_order)) <
sizeof(h)) {
return 0;
}
ring->inprogress = true;
masked_prod = xen_9pfs_mask(prod, XEN_FLEX_RING_SIZE(ring->ring_order));
masked_cons = xen_9pfs_mask(cons, XEN_FLEX_RING_SIZE(ring->ring_order));
xen_9pfs_read_packet((uint8_t *) &h, ring->ring.out, sizeof(h),
masked_prod, &masked_cons,
XEN_FLEX_RING_SIZE(ring->ring_order));
/* cannot fail, because we only handle one request per ring at a time */
pdu = pdu_alloc(&ring->priv->state);
pdu->size = le32_to_cpu(h.size_le);
pdu->id = h.id;
pdu->tag = le32_to_cpu(h.tag_le);
ring->out_size = le32_to_cpu(h.size_le);
ring->out_cons = cons + le32_to_cpu(h.size_le);
qemu_co_queue_init(&pdu->complete);
pdu_submit(pdu);
return 0;
}
static void xen_9pfs_bh(void *opaque)
{
Xen9pfsRing *ring = opaque;
xen_9pfs_receive(ring);
}
static void xen_9pfs_evtchn_event(void *opaque)
{
Xen9pfsRing *ring = opaque;
evtchn_port_t port;
port = xenevtchn_pending(ring->evtchndev);
xenevtchn_unmask(ring->evtchndev, port);
qemu_bh_schedule(ring->bh);
}
static int xen_9pfs_free(struct XenDevice *xendev)