Merge tag 'regmap-fix-v4.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap

Pull regmap fixes from Mark Brown:
 "A couple of fixes for the debugfs information on the register map,
  fixing issues with very small reads potentially causing underflows and
  wraparounds"

* tag 'regmap-fix-v4.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: debugfs: Don't bother actually printing when calculating max length
  regmap: debugfs: Ensure we don't underflow when printing access masks

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index f42f2bac6466..4c55cfbad19e 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,
@@ -432,7 +431,7 @@ static ssize_t regmap_access_read_file(struct file *file,
                 /* If we're in the region the user is trying to read */
                 if (p >= *ppos) {
                         /* ...but not beyond it */
-                        if (buf_pos >= count - 1 - tot_len)
+                        if (buf_pos + tot_len + 1 >= count)
                                 break;
 
                         /* Format the register */