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 <boqun.feng@xxxxxxxxx> Cc: Jiri Kosina <jkosina@xxxxxxx> Cc: Michael Kelley <mikelley@xxxxxxxxxxxxx> --- Michael and Jiri, I change the code because of a problem I found: https://lore.kernel.org/lkml/20200914084600.GA45838@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ , so I drop your Reviewed-by or Acked-by tag. If the update version looks good to you, may I add your tag again? Thanks in advance, and apologies for the inconvenience. Regards, Boqun drivers/hid/hid-hyperv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c index 0b6ee1dee625..978ee2aab2d4 100644 --- a/drivers/hid/hid-hyperv.c +++ b/drivers/hid/hid-hyperv.c @@ -104,8 +104,8 @@ struct synthhid_input_report { #pragma pack(pop) -#define INPUTVSC_SEND_RING_BUFFER_SIZE (40 * 1024) -#define INPUTVSC_RECV_RING_BUFFER_SIZE (40 * 1024) +#define INPUTVSC_SEND_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024) +#define INPUTVSC_RECV_RING_BUFFER_SIZE VMBUS_RING_SIZE(36 * 1024) enum pipe_prot_msg_type { -- 2.28.0
