[PATCH 5.15 146/245] serial: 8250: Remove serial_rs485 sanitization from em485

Greg Kroah-Hartman
2024-02-27T14:07:39Z

From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

[ Upstream commit 84f2faa7852e1f55d89bb0c99b3a672b87b11f87 ]

Serial core handles serial_rs485 sanitization.

When em485 init fails, there are two possible paths of entry:

1) uart_rs485_config (init path) that fully clears port->rs485 on
error.

2) ioctl path with a pre-existing, valid port->rs485 unto which the
kernel falls back on error and port->rs485 should therefore be
kept untouched. The temporary rs485 struct is not returned to
userspace in case of error so its flag don't matter.

...Thus SER_RS485_ENABLED clearing on error can/should be dropped.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-37-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/8250/8250_port.c | 18 ++----------------
1 file changed, 2 insertions(+), 16 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 45a8f76f562e7..4fce318bc83ca 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -670,13 +670,6 @@ int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485)
rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
}

- /* clamp the delays to [0, 100ms] */
- rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
- rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U);
-
- memset(rs485->padding, 0, sizeof(rs485->padding));
- port->rs485 = *rs485;
-
gpiod_set_value(port->rs485_term_gpio,
rs485->flags & SER_RS485_TERMINATE_BUS);

@@ -684,15 +677,8 @@ int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485)
* Both serial8250_em485_init() and serial8250_em485_destroy()
* are idempotent.
*/
- if (rs485->flags & SER_RS485_ENABLED) {
- int ret = serial8250_em485_init(up);
-
- if (ret) {
- rs485->flags &= ~SER_RS485_ENABLED;
- port->rs485.flags &= ~SER_RS485_ENABLED;
- }
- return ret;
- }
+ if (rs485->flags & SER_RS485_ENABLED)
+ return serial8250_em485_init(up);

serial8250_em485_destroy(up);
return 0;
--
2.43.0