mei: mei_write: revamp error path handling

1. unify common amt and regular error path and use it early in the
  function
2. fix indentation
3. propagate error code directly from copy_from_user
4. print out errors using dev_err instead of dev_dbg

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

1 files changed, 27 insertions, 48 deletions

diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index 15de4b19caa5..8dcf59d43b0d 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -621,10 +621,26 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
         mutex_lock(&dev->device_lock);
 
         if (dev->dev_state != MEI_DEV_ENABLED) {
-                mutex_unlock(&dev->device_lock);
-                return -ENODEV;
+                rets = -ENODEV;
+                goto unlock_dev;
         }
 
+        i = mei_me_cl_by_id(dev, cl->me_client_id);
+        if (i < 0) {
+                rets = -ENODEV;
+                goto unlock_dev;
+        }
+        if (length > dev->me_clients[i].props.max_msg_length || length <= 0) {
+                rets = -EMSGSIZE;
+                goto unlock_dev;
+        }
+
+        if (cl->state != MEI_FILE_CONNECTED) {
+                rets = -ENODEV;
+                dev_err(&dev->pdev->dev, "host client = %d,  is not connected to ME client = %d",
+                        cl->host_client_id, cl->me_client_id);
+                goto unlock_dev;
+        }
         if (cl == &dev->iamthif_cl) {
                 write_cb = find_amthi_read_list_entry(dev, file);
 
@@ -633,11 +649,11 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
                                         msecs_to_jiffies(IAMTHIF_READ_TIMER);
 
                         if (time_after(jiffies, timeout) ||
-                                 cl->reading_state == MEI_READ_COMPLETE) {
-                                        *offset = 0;
-                                        list_del(&write_cb->cb_list);
-                                        mei_free_cb_private(write_cb);
-                                        write_cb = NULL;
+                            cl->reading_state == MEI_READ_COMPLETE) {
+                                *offset = 0;
+                                list_del(&write_cb->cb_list);
+                                mei_free_cb_private(write_cb);
+                                write_cb = NULL;
                         }
                 }
         }
@@ -670,8 +686,8 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 
         dev_dbg(&dev->pdev->dev, "cb request size = %zd\n", length);
 
-        rets = -EFAULT;
-        if (copy_from_user(write_cb->request_buffer.data, ubuf, length))
+        rets = copy_from_user(write_cb->request_buffer.data, ubuf, length);
+        if (rets)
                 goto unlock_dev;
 
         cl->sm_state = 0;
@@ -685,29 +701,11 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
                 cl->sm_state |= MEI_WD_STATE_INDEPENDENCE_MSG_SENT;
 
         if (cl == &dev->iamthif_cl) {
-                if (dev->dev_state != MEI_DEV_ENABLED) {
-                        rets = -ENODEV;
-                        goto unlock_dev;
-                }
-                i = mei_me_cl_by_id(dev, dev->iamthif_cl.me_client_id);
-                if (i < 0) {
-                        rets = -ENODEV;
-                        goto unlock_dev;
-                }
-                if (length > dev->me_clients[i].props.max_msg_length ||
-                           length <= 0) {
-                        rets = -EMSGSIZE;
-                        goto unlock_dev;
-                }
                 rets = mei_io_cb_alloc_resp_buf(write_cb, dev->iamthif_mtu);
                 if (rets)
                         goto unlock_dev;
 
                 write_cb->major_file_operations = MEI_IOCTL;
-                if (dev->iamthif_cl.state != MEI_FILE_CONNECTED) {
-                        rets = -ENODEV;
-                        goto unlock_dev;
-                }
 
                 if (!list_empty(&dev->amthi_cmd_list.mei_cb.cb_list) ||
                                 dev->iamthif_state != MEI_IAMTHIF_IDLE) {
@@ -716,43 +714,24 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
                         dev_dbg(&dev->pdev->dev, "add amthi cb to amthi cmd waiting list\n");
                         list_add_tail(&write_cb->cb_list,
                                         &dev->amthi_cmd_list.mei_cb.cb_list);
-                        rets = length;
                 } else {
                         dev_dbg(&dev->pdev->dev, "call amthi write\n");
                         rets = amthi_write(dev, write_cb);
 
                         if (rets) {
-                                dev_dbg(&dev->pdev->dev, "amthi write failed with status = %d\n",
+                                dev_err(&dev->pdev->dev, "amthi write failed with status = %d\n",
                                     rets);
                                 goto unlock_dev;
                         }
-                        rets = length;
                 }
                 mutex_unlock(&dev->device_lock);
-                return rets;
+                return length;
         }
 
         write_cb->major_file_operations = MEI_WRITE;
 
         dev_dbg(&dev->pdev->dev, "host client = %d, ME client = %d\n",
             cl->host_client_id, cl->me_client_id);
-        if (cl->state != MEI_FILE_CONNECTED) {
-                rets = -ENODEV;
-                dev_dbg(&dev->pdev->dev, "host client = %d,  is not connected to ME client = %d",
-                    cl->host_client_id,
-                    cl->me_client_id);
-                goto unlock_dev;
-        }
-        i = mei_me_cl_by_id(dev, cl->me_client_id);
-        if (i < 0) {
-                rets = -ENODEV;
-                goto unlock_dev;
-        }
-        if (length > dev->me_clients[i].props.max_msg_length || length <= 0) {
-                rets = -EINVAL;
-                goto unlock_dev;
-        }
-
         rets = mei_flow_ctrl_creds(dev, cl);
         if (rets < 0)
                 goto unlock_dev;