mei: revamp mei_data2slots

1. Move the mei_data2slots to mei_dev.h as it will be used
by the all supported HW.
2. Change return value from u8 to u32 to catch possible overflows
3. Eliminate computing the slots number twice in the same function

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 28 insertions, 22 deletions

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 3535b2676c97..14c70b8815d8 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -153,25 +153,27 @@ static int _mei_irq_thread_close(struct mei_device *dev, s32 *slots,
 				struct mei_cl *cl,
 				struct mei_cl_cb *cmpl_list)
 {
-	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
-			sizeof(struct hbm_client_connect_request)))
-		return -EBADMSG;
+	u32 msg_slots =
+		mei_data2slots(sizeof(struct hbm_client_connect_request));
 
-	*slots -= mei_data2slots(sizeof(struct hbm_client_connect_request));
+	if (*slots < msg_slots)
+		return -EMSGSIZE;
+
+	*slots -= msg_slots;
 
 	if (mei_hbm_cl_disconnect_req(dev, cl)) {
 		cl->status = 0;
 		cb_pos->buf_idx = 0;
 		list_move_tail(&cb_pos->list, &cmpl_list->list);
-		return -EMSGSIZE;
-	} else {
-		cl->state = MEI_FILE_DISCONNECTING;
-		cl->status = 0;
-		cb_pos->buf_idx = 0;
-		list_move_tail(&cb_pos->list, &dev->ctrl_rd_list.list);
-		cl->timer_count = MEI_CONNECT_TIMEOUT;
+		return -EIO;
 	}
 
+	cl->state = MEI_FILE_DISCONNECTING;
+	cl->status = 0;
+	cb_pos->buf_idx = 0;
+	list_move_tail(&cb_pos->list, &dev->ctrl_rd_list.list);
+	cl->timer_count = MEI_CONNECT_TIMEOUT;
+
 	return 0;
 }
 
@@ -192,14 +194,15 @@ static int _mei_irq_thread_read(struct mei_device *dev,	s32 *slots,
 			struct mei_cl *cl,
 			struct mei_cl_cb *cmpl_list)
 {
-	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
-			sizeof(struct hbm_flow_control))) {
+	u32 msg_slots = mei_data2slots(sizeof(struct hbm_flow_control));
+
+	if (*slots < msg_slots) {
 		/* return the cancel routine */
 		list_del(&cb_pos->list);
-		return -EBADMSG;
+		return -EMSGSIZE;
 	}
 
-	*slots -= mei_data2slots(sizeof(struct hbm_flow_control));
+	*slots -= msg_slots;
 
 	if (mei_hbm_cl_flow_control_req(dev, cl)) {
 		cl->status = -ENODEV;
@@ -229,15 +232,19 @@ static int _mei_irq_thread_ioctl(struct mei_device *dev, s32 *slots,
 			struct mei_cl *cl,
 			struct mei_cl_cb *cmpl_list)
 {
-	if ((*slots * sizeof(u32)) < (sizeof(struct mei_msg_hdr) +
-			sizeof(struct hbm_client_connect_request))) {
+	u32 msg_slots =
+		mei_data2slots(sizeof(struct hbm_client_connect_request));
+
+	if (*slots < msg_slots) {
 		/* return the cancel routine */
 		list_del(&cb_pos->list);
-		return -EBADMSG;
+		return -EMSGSIZE;
 	}
 
+	*slots -=  msg_slots;
+
 	cl->state = MEI_FILE_CONNECTING;
-	*slots -= mei_data2slots(sizeof(struct hbm_client_connect_request));
+
 	if (mei_hbm_cl_connect_req(dev, cl)) {
 		cl->status = -ENODEV;
 		cb_pos->buf_idx = 0;
@@ -266,7 +273,7 @@ static int mei_irq_thread_write_complete(struct mei_device *dev, s32 *slots,
 	struct mei_msg_hdr mei_hdr;
 	struct mei_cl *cl = cb->cl;
 	size_t len = cb->request_buffer.size - cb->buf_idx;
-	size_t msg_slots = mei_data2slots(len);
+	u32 msg_slots = mei_data2slots(len);
 
 	mei_hdr.host_addr = cl->host_client_id;
 	mei_hdr.me_addr = cl->me_client_id;
@@ -419,8 +426,7 @@ end:
  *
  * returns 0 on success, <0 on failure.
  */
-int mei_irq_write_handler(struct mei_device *dev,
-				struct mei_cl_cb *cmpl_list)
+int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list)
 {
 
 	struct mei_cl *cl;