Many Xen PV frontends share similar code for setting up a ring page
(allocating and granting access for the backend) and for tearing it
down.

Create new service functions doing all needed steps in one go.

This requires all frontends to use a common value for an invalid
grant reference in order to make the functions idempotent.

Changes in V2:
- new patch 9 and related changes in patches 10-18

Juergen Gross (19):
  xen/blkfront: switch blkfront to use INVALID_GRANT_REF
  xen/netfront: switch netfront to use INVALID_GRANT_REF
  xen/scsifront: remove unused GRANT_INVALID_REF definition
  xen/usb: switch xen-hcd to use INVALID_GRANT_REF
  xen/drm: switch xen_drm_front to use INVALID_GRANT_REF
  xen/sound: switch xen_snd_front to use INVALID_GRANT_REF
  xen/dmabuf: switch gntdev-dmabuf to use INVALID_GRANT_REF
  xen/shbuf: switch xen-front-pgdir-shbuf to use INVALID_GRANT_REF
  xen: update ring.h
  xen/xenbus: add xenbus_setup_ring() service function
  xen/blkfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/netfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/tpmfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/drmfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/pcifront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/scsifront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/usbfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/sndfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/xenbus: eliminate xenbus_grant_ring()

 drivers/block/xen-blkfront.c                | 57 +++++---------
 drivers/char/tpm/xen-tpmfront.c             | 18 +----
 drivers/gpu/drm/xen/xen_drm_front.h         |  9 ---
 drivers/gpu/drm/xen/xen_drm_front_evtchnl.c | 43 +++--------
 drivers/net/xen-netfront.c                  | 85 +++++++--------------
 drivers/pci/xen-pcifront.c                  | 19 +----
 drivers/scsi/xen-scsifront.c                | 31 ++------
 drivers/usb/host/xen-hcd.c                  | 65 ++++------------
 drivers/xen/gntdev-dmabuf.c                 | 13 +---
 drivers/xen/xen-front-pgdir-shbuf.c         | 17 +----
 drivers/xen/xenbus/xenbus_client.c          | 82 +++++++++++++++-----
 include/xen/interface/io/ring.h             | 19 +++--
 include/xen/xenbus.h                        |  4 +-
 sound/xen/xen_snd_front_evtchnl.c           | 44 +++--------
 sound/xen/xen_snd_front_evtchnl.h           |  9 ---
 15 files changed, 179 insertions(+), 336 deletions(-)

-- 
2.34.1