mei: revamp open handler counts

Make open counter to be incremented and decremented
from mei_cl_link and mei_cl_unlik function respectively

Nfc was assuming symmetric linking API and thus open handler
count was never decreased. This patch fixes that.
We need to add separate open hander count for amthif which
is handled out of link/unlink functions and doesn't break
the symmetric API.

Last we do not waste clients slots if amthif or wd are not present
in the device. we don't need to allocates slots ahead
it is all covered by link/unlink before the devices is responding
to user space connection and thus not racing on allocation

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

drivers/misc/mei/amthif.c

@@ -58,6 +58,7 @@ void mei_amthif_reset_params(struct mei_device *dev)
 	dev->iamthif_state = MEI_IAMTHIF_IDLE;
 	dev->iamthif_timer = 0;
 	dev->iamthif_stall_timer = 0;
+	dev->iamthif_open_count = 0;
 }
 
 /**
@@ -731,8 +732,8 @@ static bool mei_clear_lists(struct mei_device *dev, struct file *file)
 */
 int mei_amthif_release(struct mei_device *dev, struct file *file)
 {
-	if (dev->open_handle_count > 0)
-		dev->open_handle_count--;
+	if (dev->iamthif_open_count > 0)
+		dev->iamthif_open_count--;
 
 	if (dev->iamthif_file_object == file &&
 	    dev->iamthif_state != MEI_IAMTHIF_IDLE) {

drivers/misc/mei/client.c

@@ -275,6 +275,7 @@ struct mei_cl_cb *mei_cl_find_read_cb(struct mei_cl *cl)
 int mei_cl_link(struct mei_cl *cl, int id)
 {
 	struct mei_device *dev;
+	long open_handle_count;
 
 	if (WARN_ON(!cl || !cl->dev))
 		return -EINVAL;
@@ -291,7 +292,8 @@ int mei_cl_link(struct mei_cl *cl, int id)
 		return -EMFILE;
 	}
 
-	if (dev->open_handle_count >= MEI_MAX_OPEN_HANDLE_COUNT) {
+	open_handle_count = dev->open_handle_count + dev->iamthif_open_count;
+	if (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;
@@ -337,6 +339,17 @@ int mei_cl_unlink(struct mei_cl *cl)
 
 	cl_dbg(dev, cl, "unlink client");
 
+	if (dev->open_handle_count > 0)
+		dev->open_handle_count--;
+
+	/* never clear the 0 bit */
+	if (cl->host_client_id)
+		clear_bit(cl->host_client_id, dev->host_clients_map);
+
+	list_del_init(&cl->link);
+
+	cl->state = MEI_FILE_INITIALIZING;
+
 	list_del_init(&cl->link);
 
 	return 0;
@@ -358,10 +371,8 @@ void mei_host_client_init(struct work_struct *work)
 	/*
 	 * Reserving the first three client IDs
 	 * 0: Reserved for MEI Bus Message communications
-	 * 1: Reserved for Watchdog
-	 * 2: Reserved for AMTHI
 	 */
-	bitmap_set(dev->host_clients_map, 0, 3);
+	bitmap_set(dev->host_clients_map, 0, 1);
 
 	for (i = 0; i < dev->me_clients_num; i++) {
 		client_props = &dev->me_clients[i].props;

drivers/misc/mei/init.c

@@ -165,12 +165,7 @@ void mei_reset(struct mei_device *dev, int interrupts_enabled)
 		/* remove entry if already in list */
 		dev_dbg(&dev->pdev->dev, "remove iamthif and wd from the file list.\n");
 		mei_cl_unlink(&dev->wd_cl);
-		if (dev->open_handle_count > 0)
-			dev->open_handle_count--;
 		mei_cl_unlink(&dev->iamthif_cl);
-		if (dev->open_handle_count > 0)
-			dev->open_handle_count--;
-
 		mei_amthif_reset_params(dev);
 		memset(&dev->wr_ext_msg, 0, sizeof(dev->wr_ext_msg));
 	}

drivers/misc/mei/main.c

@@ -141,10 +141,6 @@ static int mei_release(struct inode *inode, struct file *file)
 	    cl->host_client_id,
 	    cl->me_client_id);
 
-	if (dev->open_handle_count > 0) {
-		clear_bit(cl->host_client_id, dev->host_clients_map);
-		dev->open_handle_count--;
-	}
 	mei_cl_unlink(cl);
 
 
@@ -498,11 +494,11 @@ static int mei_ioctl_connect_client(struct file *file,
 			rets = -ENODEV;
 			goto end;
 		}
-		clear_bit(cl->host_client_id, dev->host_clients_map);
 		mei_cl_unlink(cl);
 
 		kfree(cl);
 		cl = NULL;
+		dev->iamthif_open_count++;
 		file->private_data = &dev->iamthif_cl;
 
 		client = &data->out_client_properties;

drivers/misc/mei/mei_dev.h

@@ -414,6 +414,7 @@ struct mei_device {
 	struct file *iamthif_file_object;
 	struct mei_cl iamthif_cl;
 	struct mei_cl_cb *iamthif_current_cb;
+	long iamthif_open_count;
 	int iamthif_mtu;
 	unsigned long iamthif_timer;
 	u32 iamthif_stall_timer;