On Wed, Sep 16, 2020 at 11:48:14AM +0800, Boqun Feng wrote:

For a Hyper-V vmbus, the size of the ringbuffer has two requirements:

1)	it has to take one PAGE_SIZE for the header

2)	it has to be PAGE_SIZE aligned so that double-mapping can work

VMBUS_RING_SIZE() could calculate a correct ringbuffer size which
fulfills both requirements, therefore use it to make sure vmbus work
when PAGE_SIZE != HV_HYP_PAGE_SIZE (4K).

Note that since the argument for VMBUS_RING_SIZE() is the size of
payload (data part), so it will be minus 4k (the size of header when
PAGE_SIZE = 4k) than the original value to keep the ringbuffer total
size unchanged when PAGE_SIZE = 4k.

Signed-off-by: Boqun Feng <redacted>
Cc: Michael Kelley <redacted>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Please feel free to merge through whatever tree the rest of the patches
will go.

Thanks.

-- 
Dmitry