xenbus_client: Extend interface to support multi-page ring
Originally Xen PV drivers only use single-page ring to pass along
information. This might limit the throughput between frontend and
backend.
The patch extends Xenbus driver to support multi-page ring, which in
general should improve throughput if ring is the bottleneck. Changes to
various frontend / backend to adapt to the new interface are also
included.
Affected Xen drivers:
* blkfront/back
* netfront/back
* pcifront/back
* scsifront/back
* vtpmfront
The interface is documented, as before, in xenbus_client.c.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/drivers/scsi/xen-scsifront.c b/drivers/scsi/xen-scsifront.c
index 78d9506..fad22ca 100644
--- a/drivers/scsi/xen-scsifront.c
+++ b/drivers/scsi/xen-scsifront.c
@@ -714,6 +714,7 @@
{
struct xenbus_device *dev = info->dev;
struct vscsiif_sring *sring;
+ grant_ref_t gref;
int err = -ENOMEM;
/***** Frontend to Backend ring start *****/
@@ -726,14 +727,14 @@
SHARED_RING_INIT(sring);
FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
- err = xenbus_grant_ring(dev, virt_to_mfn(sring));
+ err = xenbus_grant_ring(dev, sring, 1, &gref);
if (err < 0) {
free_page((unsigned long)sring);
xenbus_dev_fatal(dev, err,
"fail to grant shared ring (Front to Back)");
return err;
}
- info->ring_ref = err;
+ info->ring_ref = gref;
err = xenbus_alloc_evtchn(dev, &info->evtchn);
if (err) {
