mei: fix mei_poll operation

mei_poll returned with POLLIN w/o checking whether the operation
has really completed.
remove redundant check and locking in amthif specific handler

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

1 files changed, 11 insertions, 13 deletions

diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index d80867e0d803..a1ec45054988 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -542,6 +542,7 @@ static long mei_compat_ioctl(struct file *file,
  */
 static unsigned int mei_poll(struct file *file, poll_table *wait)
 {
+        unsigned long req_events = poll_requested_events(wait);
         struct mei_cl *cl = file->private_data;
         struct mei_device *dev;
         unsigned int mask = 0;
@@ -558,22 +559,19 @@ static unsigned int mei_poll(struct file *file, poll_table *wait)
                 goto out;
         }
 
-        mutex_unlock(&dev->device_lock);
-
-
-        if (cl == &dev->iamthif_cl)
-                return mei_amthif_poll(dev, file, wait);
-
-        poll_wait(file, &cl->tx_wait, wait);
-
-        mutex_lock(&dev->device_lock);
-
-        if (!mei_cl_is_connected(cl)) {
-                mask = POLLERR;
+        if (cl == &dev->iamthif_cl) {
+                mask = mei_amthif_poll(dev, file, wait);
                 goto out;
         }
 
-        mask |= (POLLIN | POLLRDNORM);
+        if (req_events & (POLLIN | POLLRDNORM)) {
+                poll_wait(file, &cl->rx_wait, wait);
+
+                if (!list_empty(&cl->rd_completed))
+                        mask |= POLLIN | POLLRDNORM;
+                else
+                        mei_cl_read_start(cl, 0, file);
+        }
 
 out:
         mutex_unlock(&dev->device_lock);