[PATCH v3 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 <boqun.feng at gmail.com>
Acked-by: Jiri Kosina <jkosina at suse.cz>
---
Hi Jiri,

Thanks for your acked-by. I make a small change in this version (casting
2 * PAGE_SIZE into int to avoid compiler warnings), and it make no
functional change. If the change is inappropriate, please let me know.

 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..8905559b3882 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, (int)(2 * PAGE_SIZE))
+#define INPUTVSC_RECV_RING_BUFFER_SIZE	max(40 * 1024, (int)(2 * PAGE_SIZE))
 
 
 enum pipe_prot_msg_type {
-- 
2.28.0