mei: simplify mei_open error handling

1. Perform simple checks first and only then attempt to allocate cl structure.
2. Remove open_handler_count test, this is already checked in mei_cl_link function
3. return -EMFILE instead of -ENOENT as expected by user space

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

2 files changed, 21 insertions, 18 deletions

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index fbd319c506e6..88770e040dd1 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -288,7 +288,13 @@ int mei_cl_link(struct mei_cl *cl, int id)
 
         if (id >= MEI_CLIENTS_MAX) {
                 dev_err(&dev->pdev->dev, "id exceded %d", MEI_CLIENTS_MAX) ;
-                return -ENOENT;
+                return -EMFILE;
+        }
+
+        if (dev->open_handle_count >= MEI_MAX_OPEN_HANDLE_COUNT) {
+                dev_err(&dev->pdev->dev, "open_handle_count exceded %d",
+                        MEI_MAX_OPEN_HANDLE_COUNT);
+                return -EMFILE;
         }
 
         if (dev->open_handle_count >= MEI_MAX_OPEN_HANDLE_COUNT) {
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index c71420ef1e37..87ab5ca1d633 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -60,48 +60,45 @@ static int mei_open(struct inode *inode, struct file *file)
 
         int err;
 
-        err = -ENODEV;
         if (!misc->parent)
-                goto out;
+                return -ENODEV;
 
         pdev = container_of(misc->parent, struct pci_dev, dev);
 
         dev = pci_get_drvdata(pdev);
         if (!dev)
-                goto out;
+                return -ENODEV;
 
         mutex_lock(&dev->device_lock);
-        err = -ENOMEM;
-        cl = mei_cl_allocate(dev);
-        if (!cl)
-                goto out_unlock;
+
+        cl = NULL;
 
         err = -ENODEV;
         if (dev->dev_state != MEI_DEV_ENABLED) {
                 dev_dbg(&dev->pdev->dev, "dev_state != MEI_ENABLED  dev_state = %s\n",
                     mei_dev_state_str(dev->dev_state));
-                goto out_unlock;
-        }
-        err = -EMFILE;
-        if (dev->open_handle_count >= MEI_MAX_OPEN_HANDLE_COUNT) {
-                dev_err(&dev->pdev->dev, "open_handle_count exceded %d",
-                        MEI_MAX_OPEN_HANDLE_COUNT);
-                goto out_unlock;
+                goto err_unlock;
         }
 
+        err = -ENOMEM;
+        cl = mei_cl_allocate(dev);
+        if (!cl)
+                goto err_unlock;
+
+        /* open_handle_count check is handled in the mei_cl_link */
         err = mei_cl_link(cl, MEI_HOST_CLIENT_ID_ANY);
         if (err)
-                goto out_unlock;
+                goto err_unlock;
 
         file->private_data = cl;
+
         mutex_unlock(&dev->device_lock);
 
         return nonseekable_open(inode, file);
 
-out_unlock:
+err_unlock:
         mutex_unlock(&dev->device_lock);
         kfree(cl);
-out:
         return err;
 }