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Subject[PATCH v2 2/4] serial: add helpers to copy serial_rs485 from/to userspace
Date
Due to the padding fields, the copying will need to do a bit more than
usual.

Move padding clearing into the helper that copies back to userspace.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/serial_core.c | 41 +++++++++++++++++++++-----------
1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 8834414a0b2f..4a4ed619ee71 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1375,10 +1375,6 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4
rs485->flags &= supported_flags;

uart_sanitize_serial_rs485_delays(port, rs485);
-
- /* Return clean padding area to userspace */
- memset(rs485->padding0, 0, sizeof(rs485->padding0));
- memset(rs485->padding1, 0, sizeof(rs485->padding1));
}

static void uart_set_rs485_termination(struct uart_port *port,
@@ -1407,6 +1403,28 @@ int uart_rs485_config(struct uart_port *port)
}
EXPORT_SYMBOL_GPL(uart_rs485_config);

+static int serial_rs485_from_user(struct serial_rs485 *rs485,
+ const struct serial_rs485 __user *rs485_user)
+{
+ if (copy_from_user(rs485, rs485_user, sizeof(*rs485)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int serial_rs485_to_user(struct serial_rs485 __user *rs485_user,
+ struct serial_rs485 *rs485)
+{
+ /* Return clean padding area to userspace */
+ memset(rs485->padding0, 0, sizeof(rs485->padding0));
+ memset(rs485->padding1, 0, sizeof(rs485->padding1));
+
+ if (copy_to_user(rs485_user, rs485, sizeof(*rs485)))
+ return -EFAULT;
+
+ return 0;
+}
+
static int uart_get_rs485_config(struct uart_port *port,
struct serial_rs485 __user *rs485_user)
{
@@ -1417,10 +1435,7 @@ static int uart_get_rs485_config(struct uart_port *port,
rs485 = port->rs485;
spin_unlock_irqrestore(&port->lock, flags);

- if (copy_to_user(rs485_user, &rs485, sizeof(rs485)))
- return -EFAULT;
-
- return 0;
+ return serial_rs485_to_user(rs485_user, &rs485);
}

static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
@@ -1433,8 +1448,9 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
if (!port->rs485_config)
return -ENOTTY;

- if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
- return -EFAULT;
+ ret = serial_rs485_from_user(&rs485, rs485_user);
+ if (ret)
+ return ret;

ret = uart_check_rs485_flags(port, &rs485);
if (ret)
@@ -1450,10 +1466,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
if (ret)
return ret;

- if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
- return -EFAULT;
-
- return 0;
+ return serial_rs485_to_user(rs485_user, &port->rs485);
}

static int uart_get_iso7816_config(struct uart_port *port,
--
2.30.2
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