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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Johan Hovold <johan@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 128/244] serial: core: return early on unsupported ioctls
Date:   Wed, 12 May 2021 16:48:19 +0200
Message-Id: <20210512144747.113560678@linuxfoundation.org>
In-Reply-To: <20210512144743.039977287@linuxfoundation.org>
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From: Johan Hovold <johan@kernel.org>

[ Upstream commit 79c5966cec7b148199386ef9933c31b999379065 ]

Drivers can return -ENOIOCTLCMD when an ioctl is not recognised to tell
the upper layers to continue looking for a handler.

This is not the case for the RS485 and ISO7816 ioctls whose handlers
should return -ENOTTY directly in case a serial driver does not
implement the corresponding methods.

Fixes: a5f276f10ff7 ("serial_core: Handle TIOC[GS]RS485 ioctls.")
Fixes: ad8c0eaa0a41 ("tty/serial_core: add ISO7816 infrastructure")
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210407095208.31838-9-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/serial_core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index ad262349703b..e2ab6524119a 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1304,7 +1304,7 @@ static int uart_set_rs485_config(struct uart_port *port,
 	unsigned long flags;
 
 	if (!port->rs485_config)
-		return -ENOIOCTLCMD;
+		return -ENOTTY;
 
 	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
 		return -EFAULT;
@@ -1328,7 +1328,7 @@ static int uart_get_iso7816_config(struct uart_port *port,
 	struct serial_iso7816 aux;
 
 	if (!port->iso7816_config)
-		return -ENOIOCTLCMD;
+		return -ENOTTY;
 
 	spin_lock_irqsave(&port->lock, flags);
 	aux = port->iso7816;
@@ -1348,7 +1348,7 @@ static int uart_set_iso7816_config(struct uart_port *port,
 	unsigned long flags;
 
 	if (!port->iso7816_config)
-		return -ENOIOCTLCMD;
+		return -ENOTTY;
 
 	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
 		return -EFAULT;
-- 
2.30.2