mei: drop unneeded client NULL check in cb structure

The pointer to client in the callback structure (cb->cl)
can't be NULL with current locking.
We can drop check and warnings as in some cases this just
uselessly complicates the code flow.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/amthif.c

@@ -360,8 +360,7 @@ int mei_amthif_write(struct mei_device *dev, struct mei_cl_cb *cb)
 void mei_amthif_run_next_cmd(struct mei_device *dev)
 {
 	struct mei_cl_cb *cb;
-	struct mei_cl_cb *next;
-	int status;
+	int ret;
 
 	if (!dev)
 		return;
@@ -376,16 +375,14 @@ void mei_amthif_run_next_cmd(struct mei_device *dev)
 
 	dev_dbg(dev->dev, "complete amthif cmd_list cb.\n");
 
-	list_for_each_entry_safe(cb, next, &dev->amthif_cmd_list.list, list) {
+	cb = list_first_entry_or_null(&dev->amthif_cmd_list.list,
+					typeof(*cb), list);
+	if (!cb)
+		return;
 	list_del(&cb->list);
-		if (!cb->cl)
-			continue;
-		status = mei_amthif_send_cmd(dev, cb);
-		if (status)
-			dev_warn(dev->dev, "amthif write failed status = %d\n",
-						status);
-		break;
-	}
+	ret =  mei_amthif_send_cmd(dev, cb);
+	if (ret)
+		dev_warn(dev->dev, "amthif write failed status = %d\n", ret);
 }
 
 
@@ -536,9 +533,6 @@ int mei_amthif_irq_read_msg(struct mei_device *dev,
 	cb = dev->iamthif_current_cb;
 	dev->iamthif_current_cb = NULL;
 
-	if (!cb->cl)
-		return -ENODEV;
-
 	dev->iamthif_stall_timer = 0;
 	cb->buf_idx = dev->iamthif_msg_buf_index;
 	cb->read_time = jiffies;

drivers/misc/mei/client.c

@@ -146,7 +146,7 @@ static void __mei_io_list_flush(struct mei_cl_cb *list,
 
 	/* enable removing everything if no cl is specified */
 	list_for_each_entry_safe(cb, next, &list->list, list) {
-		if (!cl || (cb->cl && mei_cl_cmp_id(cl, cb->cl))) {
+		if (!cl || mei_cl_cmp_id(cl, cb->cl)) {
 			list_del(&cb->list);
 			if (free)
 				mei_io_cb_free(cb);

drivers/misc/mei/hbm.c

@@ -637,11 +637,6 @@ static void mei_hbm_cl_res(struct mei_device *dev,
 	list_for_each_entry_safe(cb, next, &dev->ctrl_rd_list.list, list) {
 
 		cl = cb->cl;
-		/* this should not happen */
-		if (WARN_ON(!cl)) {
-			list_del_init(&cb->list);
-			continue;
-		}
 
 		if (cb->fop_type != fop_type)
 			continue;

drivers/misc/mei/interrupt.c

@@ -44,8 +44,6 @@ void mei_irq_compl_handler(struct mei_device *dev, struct mei_cl_cb *compl_list)
 	list_for_each_entry_safe(cb, next, &compl_list->list, list) {
 		cl = cb->cl;
 		list_del(&cb->list);
-		if (!cl)
-			continue;
 
 		dev_dbg(dev->dev, "completing call back.\n");
 		if (cl == &dev->iamthif_cl)
@@ -105,7 +103,7 @@ static int mei_cl_irq_read_msg(struct mei_device *dev,
 
 	list_for_each_entry_safe(cb, next, &dev->read_list.list, list) {
 		cl = cb->cl;
-		if (!cl || !mei_cl_is_reading(cl, mei_hdr))
+		if (!mei_cl_is_reading(cl, mei_hdr))
 			continue;
 
 		cl->reading_state = MEI_READING;
@@ -449,8 +447,6 @@ int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list)
 	list = &dev->write_waiting_list;
 	list_for_each_entry_safe(cb, next, &list->list, list) {
 		cl = cb->cl;
-		if (cl == NULL)
-			continue;
 
 		cl->status = 0;
 		list_del(&cb->list);
@@ -489,10 +485,6 @@ int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list)
 	dev_dbg(dev->dev, "complete control write list cb.\n");
 	list_for_each_entry_safe(cb, next, &dev->ctrl_wr_list.list, list) {
 		cl = cb->cl;
-		if (!cl) {
-			list_del(&cb->list);
-			return -ENODEV;
-		}
 		switch (cb->fop_type) {
 		case MEI_FOP_DISCONNECT:
 			/* send disconnect message */
@@ -530,8 +522,6 @@ int mei_irq_write_handler(struct mei_device *dev, struct mei_cl_cb *cmpl_list)
 	dev_dbg(dev->dev, "complete write list cb.\n");
 	list_for_each_entry_safe(cb, next, &dev->write_list.list, list) {
 		cl = cb->cl;
-		if (cl == NULL)
-			continue;
 		if (cl == &dev->iamthif_cl)
 			ret = mei_amthif_irq_write(cl, cb, cmpl_list);
 		else