HID: hyperv: remove unused struct synthhid_msg

struct synthhid_msg was meant to be a generic representation of the
possible protocol messages sent through VMBus. In practice, only the
header is read and depending on the message type, a cast to the actual
type is done. Also, SYNTHHID_MAX_INPUT_REPORT_SIZE constant isn't used
which I suspect is a leftover from the refactoring made while this
driver was at the staging folder.

This patch removes struct synthhid_msg and refactor the code
accordingly.

Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-hyperv.c

@@ -22,9 +22,6 @@ struct hv_input_dev_info {
 	unsigned short reserved[11];
 };
 
-/* The maximum size of a synthetic input message. */
-#define SYNTHHID_MAX_INPUT_REPORT_SIZE 16
-
 /*
  * Current version
  *
@@ -59,11 +56,6 @@ struct synthhid_msg_hdr {
 	u32 size;
 };
 
-struct synthhid_msg {
-	struct synthhid_msg_hdr header;
-	char data[]; /* Enclosed message */
-};
-
 union synthhid_version {
 	struct {
 		u16 minor_version;
@@ -251,7 +243,7 @@ static void mousevsc_on_receive(struct hv_device *device,
 				struct vmpacket_descriptor *packet)
 {
 	struct pipe_prt_msg *pipe_msg;
-	struct synthhid_msg *hid_msg;
+	struct synthhid_msg_hdr *hid_msg_hdr;
 	struct mousevsc_dev *input_dev = hv_get_drvdata(device);
 	struct synthhid_input_report *input_report;
 	size_t len;
@@ -262,9 +254,9 @@ static void mousevsc_on_receive(struct hv_device *device,
 	if (pipe_msg->type != PIPE_MESSAGE_DATA)
 		return;
 
-	hid_msg = (struct synthhid_msg *)pipe_msg->data;
+	hid_msg_hdr = (struct synthhid_msg_hdr *)pipe_msg->data;
 
-	switch (hid_msg->header.type) {
+	switch (hid_msg_hdr->type) {
 	case SYNTH_HID_PROTOCOL_RESPONSE:
 		/*
 		 * While it will be impossible for us to protect against
@@ -309,7 +301,7 @@ static void mousevsc_on_receive(struct hv_device *device,
 		break;
 	default:
 		pr_err("unsupported hid msg type - type %d len %d\n",
-		       hid_msg->header.type, hid_msg->header.size);
+		       hid_msg_hdr->type, hid_msg_hdr->size);
 		break;
 	}