Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
To:     gregkh@linuxfoundation.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Subject: [PATCH 05/10] tty: tty_buffer: switch insert functions to size_t
Date:   Wed, 16 Aug 2023 12:55:25 +0200
Message-ID: <20230816105530.3335-6-jirislaby@kernel.org>
In-Reply-To: <20230816105530.3335-1-jirislaby@kernel.org>
References: <20230816105530.3335-1-jirislaby@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

All the functions accept size_t as a size argument. They finally return
the same size (or less). It is quite unexpected that they return a
signed value and can confuse users to check for negative values.

Instead, return the same size_t as accepted to make clear we return
values >= 0, where zero in fact means failure.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
 drivers/tty/tty_buffer.c | 12 ++++++------
 include/linux/tty_flip.h | 24 ++++++++++++------------
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index c101b4ab737e..598891e53031 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -303,16 +303,16 @@ int tty_buffer_request_room(struct tty_port *port, size_t size)
 }
 EXPORT_SYMBOL_GPL(tty_buffer_request_room);
 
-int __tty_insert_flip_string_flags(struct tty_port *port, const u8 *chars,
-				   const u8 *flags, bool mutable_flags,
-				   size_t size)
+size_t __tty_insert_flip_string_flags(struct tty_port *port, const u8 *chars,
+				      const u8 *flags, bool mutable_flags,
+				      size_t size)
 {
 	bool need_flags = mutable_flags || flags[0] != TTY_NORMAL;
-	int copied = 0;
+	size_t copied = 0;
 
 	do {
-		int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
-		int space = __tty_buffer_request_room(port, goal, need_flags);
+		size_t goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
+		size_t space = __tty_buffer_request_room(port, goal, need_flags);
 		struct tty_buffer *tb = port->buf.tail;
 
 		if (unlikely(space == 0))
diff --git a/include/linux/tty_flip.h b/include/linux/tty_flip.h
index 8b781f709605..569747364ae5 100644
--- a/include/linux/tty_flip.h
+++ b/include/linux/tty_flip.h
@@ -10,9 +10,9 @@ struct tty_ldisc;
 int tty_buffer_set_limit(struct tty_port *port, int limit);
 unsigned int tty_buffer_space_avail(struct tty_port *port);
 int tty_buffer_request_room(struct tty_port *port, size_t size);
-int __tty_insert_flip_string_flags(struct tty_port *port, const u8 *chars,
-				   const u8 *flags, bool mutable_flags,
-				   size_t size);
+size_t __tty_insert_flip_string_flags(struct tty_port *port, const u8 *chars,
+				      const u8 *flags, bool mutable_flags,
+				      size_t size);
 int tty_prepare_flip_string(struct tty_port *port, u8 **chars, size_t size);
 void tty_flip_buffer_push(struct tty_port *port);
 int __tty_insert_flip_char(struct tty_port *port, u8 ch, u8 flag);
@@ -29,9 +29,9 @@ int __tty_insert_flip_char(struct tty_port *port, u8 ch, u8 flag);
  *
  * Returns: the number added.
  */
-static inline int tty_insert_flip_string_fixed_flag(struct tty_port *port,
-						    const u8 *chars, u8 flag,
-						    size_t size)
+static inline size_t tty_insert_flip_string_fixed_flag(struct tty_port *port,
+						       const u8 *chars, u8 flag,
+						       size_t size)
 {
 	return __tty_insert_flip_string_flags(port, chars, &flag, false, size);
 }
@@ -48,15 +48,15 @@ static inline int tty_insert_flip_string_fixed_flag(struct tty_port *port,
  *
  * Returns: the number added.
  */
-static inline int tty_insert_flip_string_flags(struct tty_port *port,
-					       const u8 *chars, const u8 *flags,
-					       size_t size)
+static inline size_t tty_insert_flip_string_flags(struct tty_port *port,
+						  const u8 *chars,
+						  const u8 *flags, size_t size)
 {
 	return __tty_insert_flip_string_flags(port, chars, flags, true, size);
 }
 
 
-static inline int tty_insert_flip_char(struct tty_port *port, u8 ch, u8 flag)
+static inline size_t tty_insert_flip_char(struct tty_port *port, u8 ch, u8 flag)
 {
 	struct tty_buffer *tb = port->buf.tail;
 	int change;
@@ -71,8 +71,8 @@ static inline int tty_insert_flip_char(struct tty_port *port, u8 ch, u8 flag)
 	return __tty_insert_flip_char(port, ch, flag);
 }
 
-static inline int tty_insert_flip_string(struct tty_port *port,
-		const u8 *chars, size_t size)
+static inline size_t tty_insert_flip_string(struct tty_port *port,
+					    const u8 *chars, size_t size)
 {
 	return tty_insert_flip_string_fixed_flag(port, chars, TTY_NORMAL, size);
 }
-- 
2.41.0