linux-kernel - [char-misc-next 01/27] mei: debugfs: adjust active clients print buffer

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Message-Id: <1454880943-12653-2-git-send-email-tomas.winkler@intel.com>
Date:	Sun,  7 Feb 2016 23:35:17 +0200
From:	Tomas Winkler <tomas.winkler@...el.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Alexander Usyskin <alexander.usyskin@...el.com>,
	linux-kernel@...r.kernel.org,
	Tomas Winkler <tomas.winkler@...el.com>
Subject: [char-misc-next 01/27] mei: debugfs: adjust active clients print buffer

From: Alexander Usyskin <alexander.usyskin@...el.com>

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: Alexander Usyskin <alexander.usyskin@...el.com>
Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
---
 drivers/misc/mei/debugfs.c | 29 ++++++++++++++++++++++-------
 1 file changed, 22 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/mei/debugfs.c b/drivers/misc/mei/debugfs.c
index a138d8a27ab5..9f5410b98688 100644
--- a/drivers/misc/mei/debugfs.c
+++ b/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++;
-- 
2.4.3