[char-misc-next 7/9 RESEND] mei: support polling for event notification

[Tomas Winkler <tomas.winkler@intel.com>]

Polling on priority events is translated on waiting for event
notification. One need to enable notification prior for
calling select or poll system call otherwise process
will not wait.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
---
 drivers/misc/mei/main.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index ffa70035af29..17b356f26686 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -608,6 +608,7 @@ static unsigned int mei_poll(struct file *file, poll_table *wait)
 	struct mei_cl *cl = file->private_data;
 	struct mei_device *dev;
 	unsigned int mask = 0;
+	bool notify_en;
 
 	if (WARN_ON(!cl || !cl->dev))
 		return POLLERR;
@@ -616,6 +617,7 @@ static unsigned int mei_poll(struct file *file, poll_table *wait)
 
 	mutex_lock(&dev->device_lock);
 
+	notify_en = cl->notify_en && (req_events & POLLPRI);
 
 	if (dev->dev_state != MEI_DEV_ENABLED ||
 	    !mei_cl_is_connected(cl)) {
@@ -628,6 +630,12 @@ static unsigned int mei_poll(struct file *file, poll_table *wait)
 		goto out;
 	}
 
+	if (notify_en) {
+		poll_wait(file, &cl->ev_wait, wait);
+		if (cl->notify_ev)
+			mask |= POLLPRI;
+	}
+
 	if (req_events & (POLLIN | POLLRDNORM)) {
 		poll_wait(file, &cl->rx_wait, wait);
 
-- 
2.4.3