mei: debugfs: adjust active clients print buffer

In case of many active host clients clients (41 and more) 1K buffer
is not enough for full information print.
Calculate buffer size according to real clients number.
Signed-off-by: NAlexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/debugfs.c

@@ -50,6 +50,7 @@ static ssize_t mei_dbgfs_read_meclients(struct file *fp, char __user *ubuf,
 	}
 
 	pos += scnprintf(buf + pos, bufsz - pos, HDR);
+#undef HDR
 
 	/*  if the driver is not enabled the list won't be consistent */
 	if (dev->dev_state != MEI_DEV_ENABLED)
@@ -90,23 +91,37 @@ static ssize_t mei_dbgfs_read_active(struct file *fp, char __user *ubuf,
 {
 	struct mei_device *dev = fp->private_data;
 	struct mei_cl *cl;
-	const size_t bufsz = 1024;
+	size_t bufsz = 1;
 	char *buf;
 	int i = 0;
 	int pos = 0;
 	int ret;
 
+#define HDR "   |me|host|state|rd|wr|\n"
+
 	if (!dev)
 		return -ENODEV;
 
+	mutex_lock(&dev->device_lock);
+
+	/*
+	 * if the driver is not enabled the list won't be consistent,
+	 * we output empty table
+	 */
+	if (dev->dev_state == MEI_DEV_ENABLED)
+		list_for_each_entry(cl, &dev->file_list, link)
+			bufsz++;
+
+	bufsz *= sizeof(HDR) + 1;
+
 	buf = kzalloc(bufsz, GFP_KERNEL);
-	if  (!buf)
+	if  (!buf) {
+		mutex_unlock(&dev->device_lock);
 		return -ENOMEM;
+	}
 
-	pos += scnprintf(buf + pos, bufsz - pos,
-			"  |me|host|state|rd|wr|\n");
-
-	mutex_lock(&dev->device_lock);
+	pos += scnprintf(buf + pos, bufsz - pos, HDR);
+#undef HDR
 
 	/*  if the driver is not enabled the list won't be consistent */
 	if (dev->dev_state != MEI_DEV_ENABLED)
@@ -115,7 +130,7 @@ static ssize_t mei_dbgfs_read_active(struct file *fp, char __user *ubuf,
 	list_for_each_entry(cl, &dev->file_list, link) {
 
 		pos += scnprintf(buf + pos, bufsz - pos,
-			"%2d|%2d|%4d|%5d|%2d|%2d|\n",
+			"%3d|%2d|%4d|%5d|%2d|%2d|\n",
 			i, mei_cl_me_id(cl), cl->host_client_id, cl->state,
 			!list_empty(&cl->rd_completed), cl->writing_state);
 		i++;