[PATCH] HID: hyperv: make sure input buffer is big enough

From: David Herrmann
Date: Thu Dec 19 2013 - 06:33:09 EST


We need at least HID_MAX_BUFFER_SIZE (4096) bytes as input buffer. HID
core depends on this as it requires every input report to be at least as
big as advertised.

Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
---
Hi

Same as for the HIDP patch, if there's a way to avoid the extra copy, please
provide a better patch.

Thanks
David

drivers/hid/hid-hyperv.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c
index 8fae6d1..c24908f 100644
--- a/drivers/hid/hid-hyperv.c
+++ b/drivers/hid/hid-hyperv.c
@@ -157,6 +157,7 @@ struct mousevsc_dev {
u32 report_desc_size;
struct hv_input_dev_info hid_dev_info;
struct hid_device *hid_device;
+ u8 input_buf[HID_MAX_BUFFER_SIZE];
};


@@ -256,6 +257,7 @@ static void mousevsc_on_receive(struct hv_device *device,
struct synthhid_msg *hid_msg;
struct mousevsc_dev *input_dev = hv_get_drvdata(device);
struct synthhid_input_report *input_report;
+ size_t len;

pipe_msg = (struct pipe_prt_msg *)((unsigned long)packet +
(packet->offset8 << 3));
@@ -300,9 +302,12 @@ static void mousevsc_on_receive(struct hv_device *device,
(struct synthhid_input_report *)pipe_msg->data;
if (!input_dev->init_complete)
break;
- hid_input_report(input_dev->hid_device,
- HID_INPUT_REPORT, input_report->buffer,
- input_report->header.size, 1);
+
+ len = min(input_report->header.size,
+ (u32)sizeof(input_dev->input_buf));
+ memcpy(input_dev->input_buf, input_report->buffer, len);
+ hid_input_report(input_dev->hid_device, HID_INPUT_REPORT,
+ input_dev->input_buf, len, 1);
break;
default:
pr_err("unsupported hid msg type - type %d len %d",
--
1.8.5.1

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