Re: [RFC v2 09/11] HID: hyperv: Make ringbuffer at least take two pages

[Jiri Kosina]

On Wed, 2 Sep 2020, Boqun Feng wrote:

> When PAGE_SIZE > HV_HYP_PAGE_SIZE, we need the ringbuffer size to be at
> least 2 * PAGE_SIZE: one page for the header and at least one page of
> the data part (because of the alignment requirement for double mapping).
> 
> So make sure the ringbuffer sizes to be at least 2 * PAGE_SIZE when
> using vmbus_open() to establish the vmbus connection.
> 
> Signed-off-by: Boqun Feng 

Acked-by: Jiri Kosina 

-- 
Jiri Kosina
SUSE Labs

[RFC v2 09/11] HID: hyperv: Make ringbuffer at least take two pages

[Boqun Feng]

When PAGE_SIZE > HV_HYP_PAGE_SIZE, we need the ringbuffer size to be at
least 2 * PAGE_SIZE: one page for the header and at least one page of
the data part (because of the alignment requirement for double mapping).

So make sure the ringbuffer sizes to be at least 2 * PAGE_SIZE when
using vmbus_open() to establish the vmbus connection.

Signed-off-by: Boqun Feng 
---
 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..dff032f17ad0 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 max(40 * 1024, 2 * PAGE_SIZE)
+#define INPUTVSC_RECV_RING_BUFFER_SIZE max(40 * 1024, 2 * PAGE_SIZE)
 
 
 enum pipe_prot_msg_type {
-- 
2.28.0