[PATCH 2/4] n_tty: simplify and sanitize zero_buffer()

["Jiri Slaby (SUSE)" <jirislaby@kernel.org>]

* Make 'tty' parameter const as we only look at tty flags here.
* Make 'size' parameter of size_t type as everyone passes that and
  memset() (the consumer) expects size_t too. So be consistent.
* Remove redundant local variables, place the content directly to the
  'if'.
* Use 0 instead of 0x00 in memset(). The former is more obvious.

No functional changes expected.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/tty/n_tty.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 1599012f20c8..c1859ae263eb 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -158,13 +158,10 @@ static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i)
 }
 
 /* If we are not echoing the data, perhaps this is a secret so erase it */
-static void zero_buffer(struct tty_struct *tty, u8 *buffer, int size)
+static void zero_buffer(const struct tty_struct *tty, u8 *buffer, size_t size)
 {
-	bool icanon = !!L_ICANON(tty);
-	bool no_echo = !L_ECHO(tty);
-
-	if (icanon && no_echo)
-		memset(buffer, 0x00, size);
+	if (L_ICANON(tty) && !L_ECHO(tty))
+		memset(buffer, 0, size);
 }
 
 static void tty_copy(struct tty_struct *tty, void *to, size_t tail, size_t n)
-- 
2.41.0