[3.16.y-ckt stable] Patch "regmap: debugfs: Don't bother actually printing when calculating max length" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    regmap: debugfs: Don't bother actually printing when calculating max length

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt20.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 19334ed937d05b6a9345ef8c615a8f9f19c65136 Mon Sep 17 00:00:00 2001
From: Mark Brown <broonie at kernel.org>
Date: Sat, 19 Sep 2015 07:12:34 -0700
Subject: regmap: debugfs: Don't bother actually printing when calculating max
 length

commit 176fc2d5770a0990eebff903ba680d2edd32e718 upstream.

The in kernel snprintf() will conveniently return the actual length of
the printed string even if not given an output beffer at all so just do
that rather than relying on the user to pass in a suitable buffer,
ensuring that we don't need to worry if the buffer was truncated due to
the size of the buffer passed in.

Reported-by: Rasmus Villemoes <linux at rasmusvillemoes.dk>
Signed-off-by: Mark Brown <broonie at kernel.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/base/regmap/regmap-debugfs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index c11e72f7ab51..a79104a2b033 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -32,8 +32,7 @@ static DEFINE_MUTEX(regmap_debugfs_early_lock);
 /* Calculate the length of a fixed format  */
 static size_t regmap_calc_reg_len(int max_val, char *buf, size_t buf_size)
 {
-	snprintf(buf, buf_size, "%x", max_val);
-	return strlen(buf);
+	return snprintf(NULL, 0, "%x", max_val);
 }

 static ssize_t regmap_name_read_file(struct file *file,