[PATCH 0/4] Drivers: hv: vmbus: Make in-place consumption always possible

[kys]

From: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>

Make in-place consumption of VMBus packets always possible. Currently we forbid
it when a packet 'wraps around' the ring so we can't provide a single
pointer to it.

The idea if this series is dead simple: let's make a single virtual mapping
for two copies (actually, two sets of pages which consist the ring buffer)
of the ring buffer. With such a mapping we can always provide a pointers
for in-place consumption to drivers. Copy path can also benefit from such
mappings as we eliminate the need for conditional checking in copy_to/
copy_from functions and use a single memcpy().

Vitaly Kuznetsov (4):
  Drivers: hv: cleanup vmbus_open() for wrap around mappings
  Drivers: hv: ring_buffer: wrap around mappings for ring buffers
  Drivers: hv: ring_buffer: use wrap around mappings in
    hv_copy{from,to}_ringbuffer()
  Drivers: hv: ring_buffer: count on wrap around mappings in
    get_next_pkt_raw()

 drivers/hv/channel.c      |   68 +++++++++++++++++++++++----------------------
 drivers/hv/hyperv_vmbus.h |    4 +-
 drivers/hv/ring_buffer.c  |   61 +++++++++++++++++++++++-----------------
 include/linux/hyperv.h    |   32 +++++++--------------
 4 files changed, 83 insertions(+), 82 deletions(-)

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1.7.4.1