[PATCH 3/3] serial: Add kserial_rs485 to avoid wasted space due to .padding

From: Ilpo Järvinen
Date: Fri Aug 26 2022 - 10:47:10 EST

Struct serial_rs485 has a .padding field to make uapi updates easier.
It wastes space, however. Create struct kserial_rs485 which is a kerner
counterpart w/o padding.

kernel_serial_rs485_to_user_rs485()'s rs485 can now become const as
padding is dealt within the local variable.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
---
.../driver-api/serial/serial-rs485.rst | 2 +-
drivers/tty/serial/8250/8250.h | 4 +-
drivers/tty/serial/8250/8250_dwlib.c | 6 +--
drivers/tty/serial/8250/8250_exar.c | 12 ++---
drivers/tty/serial/8250/8250_fintek.c | 6 +--
drivers/tty/serial/8250/8250_lpc18xx.c | 4 +-
drivers/tty/serial/8250/8250_pci.c | 4 +-
drivers/tty/serial/8250/8250_port.c | 4 +-
drivers/tty/serial/amba-pl011.c | 4 +-
drivers/tty/serial/ar933x_uart.c | 8 ++--
drivers/tty/serial/atmel_serial.c | 4 +-
drivers/tty/serial/fsl_lpuart.c | 6 +--
drivers/tty/serial/imx.c | 6 +--
drivers/tty/serial/max310x.c | 4 +-
drivers/tty/serial/mcf.c | 4 +-
drivers/tty/serial/omap-serial.c | 6 +--
drivers/tty/serial/sc16is7xx.c | 6 +--
drivers/tty/serial/serial_core.c | 48 +++++++++++++------
drivers/tty/serial/stm32-usart.c | 12 ++---
include/linux/serial_core.h | 20 ++++++--
include/uapi/linux/serial.h | 3 +-
21 files changed, 104 insertions(+), 69 deletions(-)

diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index 6ebad75c74ed..7e496336a01b 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -41,7 +41,7 @@ RS485 Serial Communications
implement the rs485_config callback and provide rs485_supported in the
uart_port structure. The serial core calls rs485_config to do the device
specific part in response to TIOCSRS485 ioctl (see below). The rs485_config
- callback receives a pointer to a sanitizated serial_rs485 structure. The
+ callback receives a pointer to a sanitizated kserial_rs485 structure. The
serial_rs485 userspace provides is sanitized before calling rs485_config
using rs485_supported that indicates what RS485 features the driver supports
for the uart_port. TIOCGRS485 ioctl can be used to read back the
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 287153d32536..4e22f8d50e91 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -204,11 +204,11 @@ void serial8250_rpm_get_tx(struct uart_8250_port *p);
void serial8250_rpm_put_tx(struct uart_8250_port *p);

int serial8250_em485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485);
+ struct kserial_rs485 *rs485);
void serial8250_em485_start_tx(struct uart_8250_port *p);
void serial8250_em485_stop_tx(struct uart_8250_port *p);
void serial8250_em485_destroy(struct uart_8250_port *p);
-extern struct serial_rs485 serial8250_em485_supported;
+extern struct kserial_rs485 serial8250_em485_supported;

/* MCR <-> TIOCM conversion */
static inline int serial8250_TIOCM_to_MCR(int tiocm)
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c
index dbe4d44f60d4..a628ed2c235b 100644
--- a/drivers/tty/serial/8250/8250_dwlib.c
+++ b/drivers/tty/serial/8250/8250_dwlib.c
@@ -134,7 +134,7 @@ static void dw8250_update_rar(struct uart_port *p, u32 addr)
dw8250_writel_ext(p, DW_UART_RE_EN, re_en);
}

-static void dw8250_rs485_set_addr(struct uart_port *p, struct serial_rs485 *rs485,
+static void dw8250_rs485_set_addr(struct uart_port *p, struct kserial_rs485 *rs485,
struct ktermios *termios)
{
u32 lcr = dw8250_readl_ext(p, DW_UART_LCR_EXT);
@@ -177,7 +177,7 @@ static void dw8250_rs485_set_addr(struct uart_port *p, struct serial_rs485 *rs48
}

static int dw8250_rs485_config(struct uart_port *p, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
u32 tcr;

@@ -232,7 +232,7 @@ static bool dw8250_detect_rs485_hw(struct uart_port *p)
return reg;
}

-static const struct serial_rs485 dw8250_rs485_supported = {
+static const struct kserial_rs485 dw8250_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX | SER_RS485_RTS_ON_SEND |
SER_RS485_RTS_AFTER_SEND | SER_RS485_ADDRB | SER_RS485_ADDR_RECV |
SER_RS485_ADDR_DEST,
diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index 314a05e009df..9fef2056a9b5 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -113,8 +113,8 @@ struct exar8250;

struct exar8250_platform {
int (*rs485_config)(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485);
- const struct serial_rs485 *rs485_supported;
+ struct kserial_rs485 *rs485);
+ const struct kserial_rs485 *rs485_supported;
int (*register_gpio)(struct pci_dev *, struct uart_8250_port *);
void (*unregister_gpio)(struct uart_8250_port *);
};
@@ -411,7 +411,7 @@ static void xr17v35x_unregister_gpio(struct uart_8250_port *port)
}

static int generic_rs485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
bool is_rs485 = !!(rs485->flags & SER_RS485_ENABLED);
u8 __iomem *p = port->membase;
@@ -431,7 +431,7 @@ static int generic_rs485_config(struct uart_port *port, struct ktermios *termios
return 0;
}

-static const struct serial_rs485 generic_rs485_supported = {
+static const struct kserial_rs485 generic_rs485_supported = {
.flags = SER_RS485_ENABLED,
};

@@ -443,7 +443,7 @@ static const struct exar8250_platform exar8250_default_platform = {
};

static int iot2040_rs485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
bool is_rs485 = !!(rs485->flags & SER_RS485_ENABLED);
u8 __iomem *p = port->membase;
@@ -475,7 +475,7 @@ static int iot2040_rs485_config(struct uart_port *port, struct ktermios *termios
return generic_rs485_config(port, termios, rs485);
}

-static const struct serial_rs485 iot2040_rs485_supported = {
+static const struct kserial_rs485 iot2040_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX | SER_RS485_TERMINATE_BUS,
};

diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
index 65b6b3cbaff6..d3d2e25dd06b 100644
--- a/drivers/tty/serial/8250/8250_fintek.c
+++ b/drivers/tty/serial/8250/8250_fintek.c
@@ -192,7 +192,7 @@ static int fintek_8250_get_ldn_range(struct fintek_8250 *pdata, int *min,
}

static int fintek_8250_rs485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
uint8_t config = 0;
struct fintek_8250 *pdata = port->private_data;
@@ -411,13 +411,13 @@ static int probe_setup_port(struct fintek_8250 *pdata,
}

/* Only the first port supports delays */
-static const struct serial_rs485 fintek_8250_rs485_supported_port0 = {
+static const struct kserial_rs485 fintek_8250_rs485_supported_port0 = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1,
};

-static const struct serial_rs485 fintek_8250_rs485_supported = {
+static const struct kserial_rs485 fintek_8250_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
};

diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c
index 6dc85aaba5d0..0619427683cf 100644
--- a/drivers/tty/serial/8250/8250_lpc18xx.c
+++ b/drivers/tty/serial/8250/8250_lpc18xx.c
@@ -33,7 +33,7 @@ struct lpc18xx_uart_data {
};

static int lpc18xx_rs485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct uart_8250_port *up = up_to_u8250p(port);
u32 rs485_ctrl_reg = 0;
@@ -81,7 +81,7 @@ static void lpc18xx_uart_serial_out(struct uart_port *p, int offset, int value)
writel(value, p->membase + offset);
}

-static const struct serial_rs485 lpc18xx_rs485_supported = {
+static const struct kserial_rs485 lpc18xx_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
.delay_rts_after_send = 1,
/* Delay RTS before send is not supported */
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 6f66dc2ebacc..8675b0d9658d 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1554,7 +1554,7 @@ pci_brcm_trumanage_setup(struct serial_private *priv,

/* We should do proper H/W transceiver setting before change to RS485 mode */
static int pci_fintek_rs485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct pci_dev *pci_dev = to_pci_dev(port->dev);
u8 setting;
@@ -1583,7 +1583,7 @@ static int pci_fintek_rs485_config(struct uart_port *port, struct ktermios *term
return 0;
}

-static const struct serial_rs485 pci_fintek_rs485_supported = {
+static const struct kserial_rs485 pci_fintek_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND,
/* F81504/508/512 does not support RTS delay before or after send */
};
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 39b35a61958c..2345b6fbac6d 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -647,7 +647,7 @@ void serial8250_em485_destroy(struct uart_8250_port *p)
}
EXPORT_SYMBOL_GPL(serial8250_em485_destroy);

-struct serial_rs485 serial8250_em485_supported = {
+struct kserial_rs485 serial8250_em485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
SER_RS485_TERMINATE_BUS | SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
@@ -665,7 +665,7 @@ EXPORT_SYMBOL_GPL(serial8250_em485_supported);
* hardware, relying on software emulation instead.
*/
int serial8250_em485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct uart_8250_port *up = up_to_u8250p(port);

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 15f0e4d88c5a..e78cd0759dc1 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2215,7 +2215,7 @@ static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser)
}

static int pl011_rs485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct uart_amba_port *uap =
container_of(port, struct uart_amba_port, port);
@@ -2765,7 +2765,7 @@ static int pl011_register_port(struct uart_amba_port *uap)
return ret;
}

-static const struct serial_rs485 pl011_rs485_supported = {
+static const struct kserial_rs485 pl011_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c
index 32caeac12985..30c716b4a105 100644
--- a/drivers/tty/serial/ar933x_uart.c
+++ b/drivers/tty/serial/ar933x_uart.c
@@ -391,7 +391,7 @@ static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
{
struct circ_buf *xmit = &up->port.state->xmit;
- struct serial_rs485 *rs485conf = &up->port.rs485;
+ struct kserial_rs485 *rs485conf = &up->port.rs485;
int count;
bool half_duplex_send = false;

@@ -581,7 +581,7 @@ static const struct uart_ops ar933x_uart_ops = {
};

static int ar933x_config_rs485(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485conf)
+ struct kserial_rs485 *rs485conf)
{
return 0;
}
@@ -693,8 +693,8 @@ static struct uart_driver ar933x_uart_driver = {
.cons = NULL, /* filled in runtime */
};

-static const struct serial_rs485 ar933x_no_rs485 = {};
-static const struct serial_rs485 ar933x_rs485_supported = {
+static const struct kserial_rs485 ar933x_no_rs485 = {};
+static const struct kserial_rs485 ar933x_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
};

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 30ba9eef7b39..be0296714585 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -284,7 +284,7 @@ static void atmel_tasklet_schedule(struct atmel_uart_port *atmel_port,

/* Enable or disable the rs485 support */
static int atmel_config_rs485(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485conf)
+ struct kserial_rs485 *rs485conf)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int mode;
@@ -2471,7 +2471,7 @@ static const struct uart_ops atmel_pops = {
#endif
};

-static const struct serial_rs485 atmel_rs485_supported = {
+static const struct kserial_rs485 atmel_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1,
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index f6c33cd228c8..7b28cb8bee1e 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1374,7 +1374,7 @@ static void lpuart_dma_rx_free(struct uart_port *port)
}

static int lpuart_config_rs485(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct lpuart_port *sport = container_of(port,
struct lpuart_port, port);
@@ -1404,7 +1404,7 @@ static int lpuart_config_rs485(struct uart_port *port, struct ktermios *termios,
}

static int lpuart32_config_rs485(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct lpuart_port *sport = container_of(port,
struct lpuart_port, port);
@@ -2633,7 +2633,7 @@ static struct uart_driver lpuart_reg = {
.cons = LPUART_CONSOLE,
};

-static const struct serial_rs485 lpuart_rs485_supported = {
+static const struct kserial_rs485 lpuart_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
/* delay_rts_* and RX_DURING_TX are not supported */
};
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 522445a8f666..0768e8270153 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1908,7 +1908,7 @@ static void imx_uart_poll_put_char(struct uart_port *port, unsigned char c)

/* called with port.lock taken and irqs off or from .probe without locking */
static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485conf)
+ struct kserial_rs485 *rs485conf)
{
struct imx_port *sport = (struct imx_port *)port;
u32 ucr2;
@@ -2196,8 +2196,8 @@ static enum hrtimer_restart imx_trigger_stop_tx(struct hrtimer *t)
return HRTIMER_NORESTART;
}

-static const struct serial_rs485 imx_no_rs485 = {}; /* No RS485 if no RTS */
-static const struct serial_rs485 imx_rs485_supported = {
+static const struct kserial_rs485 imx_no_rs485 = {}; /* No RS485 if no RTS */
+static const struct kserial_rs485 imx_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index ab10ca4a45b5..6a8ab63d1072 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -1037,7 +1037,7 @@ static void max310x_rs_proc(struct work_struct *ws)
}

static int max310x_rs485_config(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct max310x_one *one = to_max310x_port(port);

@@ -1257,7 +1257,7 @@ static int max310x_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
}
#endif

-static const struct serial_rs485 max310x_rs485_supported = {
+static const struct kserial_rs485 max310x_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1,
diff --git a/drivers/tty/serial/mcf.c b/drivers/tty/serial/mcf.c
index f4aaaadd0742..9c86218ae29d 100644
--- a/drivers/tty/serial/mcf.c
+++ b/drivers/tty/serial/mcf.c
@@ -432,7 +432,7 @@ static int mcf_verify_port(struct uart_port *port, struct serial_struct *ser)

/* Enable or disable the RS485 support */
static int mcf_config_rs485(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
unsigned char mr1, mr2;

@@ -453,7 +453,7 @@ static int mcf_config_rs485(struct uart_port *port, struct ktermios *termios,
return 0;
}

-static const struct serial_rs485 mcf_rs485_supported = {
+static const struct kserial_rs485 mcf_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_AFTER_SEND,
};

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 0aa666e247d5..013d843833a9 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1325,7 +1325,7 @@ static inline void serial_omap_add_console_port(struct uart_omap_port *up)
/* Enable or disable the rs485 support */
static int
serial_omap_config_rs485(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct uart_omap_port *up = to_uart_omap_port(port);
unsigned int mode;
@@ -1516,7 +1516,7 @@ static struct omap_uart_port_info *of_get_uart_port_info(struct device *dev)
static int serial_omap_probe_rs485(struct uart_omap_port *up,
struct device *dev)
{
- struct serial_rs485 *rs485conf = &up->port.rs485;
+ struct kserial_rs485 *rs485conf = &up->port.rs485;
struct device_node *np = dev->of_node;
enum gpiod_flags gflags;
int ret;
@@ -1559,7 +1559,7 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
return 0;
}

-static const struct serial_rs485 serial_omap_rs485_supported = {
+static const struct kserial_rs485 serial_omap_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 259e08cc347c..e21f30d9fb2f 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -836,7 +836,7 @@ static void sc16is7xx_reconf_rs485(struct uart_port *port)
const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT |
SC16IS7XX_EFCR_RTS_INVERT_BIT;
u32 efcr = 0;
- struct serial_rs485 *rs485 = &port->rs485;
+ struct kserial_rs485 *rs485 = &port->rs485;
unsigned long irqflags;

spin_lock_irqsave(&port->lock, irqflags);
@@ -1128,7 +1128,7 @@ static void sc16is7xx_set_termios(struct uart_port *port,
}

static int sc16is7xx_config_rs485(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
@@ -1353,7 +1353,7 @@ static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip,
}
#endif

-static const struct serial_rs485 sc16is7xx_rs485_supported = {
+static const struct kserial_rs485 sc16is7xx_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_AFTER_SEND,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1, /* Not supported but keep returning -EINVAL */
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 6d57cfdeda9d..4e2ffee2cabc 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1291,7 +1291,7 @@ static int uart_get_icount(struct tty_struct *tty,
SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
SER_RS485_TERMINATE_BUS)

-static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
+static int uart_check_rs485_flags(struct uart_port *port, struct kserial_rs485 *rs485)
{
u32 flags = rs485->flags;

@@ -1320,7 +1320,7 @@ static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *r
}

static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
- struct serial_rs485 *rs485)
+ struct kserial_rs485 *rs485)
{
if (!port->rs485_supported.delay_rts_before_send) {
if (rs485->delay_rts_before_send) {
@@ -1351,7 +1351,7 @@ static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
}
}

-static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
+static void uart_sanitize_serial_rs485(struct uart_port *port, struct kserial_rs485 *rs485)
{
u32 supported_flags = port->rs485_supported.flags;

@@ -1378,7 +1378,7 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4
}

static void uart_set_rs485_termination(struct uart_port *port,
- const struct serial_rs485 *rs485)
+ const struct kserial_rs485 *rs485)
{
if (!(rs485->flags & SER_RS485_ENABLED))
return;
@@ -1389,7 +1389,7 @@ static void uart_set_rs485_termination(struct uart_port *port,

int uart_rs485_config(struct uart_port *port)
{
- struct serial_rs485 *rs485 = &port->rs485;
+ struct kserial_rs485 *rs485 = &port->rs485;
int ret;

uart_sanitize_serial_rs485(port, rs485);
@@ -1403,23 +1403,30 @@ int uart_rs485_config(struct uart_port *port)
}
EXPORT_SYMBOL_GPL(uart_rs485_config);

-static int user_rs485_to_kernel_serial_rs485(struct serial_rs485 *rs485,
+static int user_rs485_to_kernel_serial_rs485(struct kserial_rs485 *rs485,
const struct serial_rs485 __user *rs485_user)
{
- if (copy_from_user(rs485, rs485_user, sizeof(*rs485)))
+ struct serial_rs485 rs485_uapi;
+
+ if (copy_from_user(&rs485_uapi, rs485_user, sizeof(*rs485)))
return -EFAULT;

+ *rs485 = *((struct kserial_rs485 *)&rs485_uapi);
+
return 0;
}

static int kernel_serial_rs485_to_user_rs485(struct serial_rs485 __user *rs485_user,
- struct serial_rs485 *rs485)
+ const struct kserial_rs485 *rs485)
{
+ struct serial_rs485 rs485_uapi;
+
+ *((struct kserial_rs485 *)&rs485_uapi) = *rs485;
/* Return clean padding area to userspace */
- memset(rs485->padding0, 0, sizeof(rs485->padding0));
- memset(rs485->padding1, 0, sizeof(rs485->padding1));
+ memset(rs485_uapi.padding0, 0, sizeof(rs485_uapi.padding0));
+ memset(rs485_uapi.padding1, 0, sizeof(rs485_uapi.padding1));

- if (copy_to_user(rs485_user, rs485, sizeof(*rs485)))
+ if (copy_to_user(rs485_user, &rs485_uapi, sizeof(rs485_uapi)))
return -EFAULT;

return 0;
@@ -1429,7 +1436,7 @@ static int uart_get_rs485_config(struct uart_port *port,
struct serial_rs485 __user *rs485_user)
{
unsigned long flags;
- struct serial_rs485 rs485;
+ struct kserial_rs485 rs485;

spin_lock_irqsave(&port->lock, flags);
rs485 = port->rs485;
@@ -1441,7 +1448,7 @@ static int uart_get_rs485_config(struct uart_port *port,
static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
struct serial_rs485 __user *rs485_user)
{
- struct serial_rs485 rs485;
+ struct kserial_rs485 rs485;
int ret;
unsigned long flags;

@@ -3415,7 +3422,7 @@ EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
*/
int uart_get_rs485_mode(struct uart_port *port)
{
- struct serial_rs485 *rs485conf = &port->rs485;
+ struct kserial_rs485 *rs485conf = &port->rs485;
struct device *dev = port->dev;
u32 rs485_delay[2];
int ret;
@@ -3471,6 +3478,19 @@ int uart_get_rs485_mode(struct uart_port *port)
}
EXPORT_SYMBOL_GPL(uart_get_rs485_mode);

+/* Compile-time asserts for kserial_rs485 and serial_rs485 equality (except padding) */
+static_assert(offsetof(struct kserial_rs485, flags) ==
+ offsetof(struct serial_rs485, flags));
+static_assert(offsetof(struct kserial_rs485, delay_rts_before_send) ==
+ offsetof(struct serial_rs485, delay_rts_before_send));
+static_assert(offsetof(struct kserial_rs485, delay_rts_after_send) ==
+ offsetof(struct serial_rs485, delay_rts_after_send));
+static_assert(offsetof(struct kserial_rs485, addr_recv) ==
+ offsetof(struct serial_rs485, addr_recv));
+static_assert(offsetof(struct kserial_rs485, addr_dest) ==
+ offsetof(struct serial_rs485, addr_dest));
+static_assert(sizeof(struct kserial_rs485) <= sizeof(struct serial_rs485));
+
/* Compile-time assertions for serial_rs485 layout */
static_assert(offsetof(struct serial_rs485, padding) ==
(offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 2c85dbf165c4..8606bda9f7fa 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -169,7 +169,7 @@ static void stm32_usart_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
}

static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *termios,
- struct serial_rs485 *rs485conf)
+ struct kserial_rs485 *rs485conf)
{
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
@@ -220,7 +220,7 @@ static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter
static int stm32_usart_init_rs485(struct uart_port *port,
struct platform_device *pdev)
{
- struct serial_rs485 *rs485conf = &port->rs485;
+ struct kserial_rs485 *rs485conf = &port->rs485;

rs485conf->flags = 0;
rs485conf->delay_rts_before_send = 0;
@@ -532,7 +532,7 @@ static void stm32_usart_tc_interrupt_disable(struct uart_port *port)
static void stm32_usart_rs485_rts_enable(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
- struct serial_rs485 *rs485conf = &port->rs485;
+ struct kserial_rs485 *rs485conf = &port->rs485;

if (stm32_port->hw_flow_control ||
!(rs485conf->flags & SER_RS485_ENABLED))
@@ -550,7 +550,7 @@ static void stm32_usart_rs485_rts_enable(struct uart_port *port)
static void stm32_usart_rs485_rts_disable(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
- struct serial_rs485 *rs485conf = &port->rs485;
+ struct kserial_rs485 *rs485conf = &port->rs485;

if (stm32_port->hw_flow_control ||
!(rs485conf->flags & SER_RS485_ENABLED))
@@ -1094,7 +1094,7 @@ static void stm32_usart_set_termios(struct uart_port *port,
struct stm32_port *stm32_port = to_stm32_port(port);
const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
const struct stm32_usart_config *cfg = &stm32_port->info->cfg;
- struct serial_rs485 *rs485conf = &port->rs485;
+ struct kserial_rs485 *rs485conf = &port->rs485;
unsigned int baud, bits;
u32 usartdiv, mantissa, fraction, oversampling;
tcflag_t cflag = termios->c_cflag;
@@ -1446,7 +1446,7 @@ static void stm32_usart_deinit_port(struct stm32_port *stm32port)
clk_disable_unprepare(stm32port->clk);
}

-static const struct serial_rs485 stm32_rs485_supported = {
+static const struct kserial_rs485 stm32_rs485_supported = {
.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND |
SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index aef3145f2032..3fe02e74873a 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -31,6 +31,20 @@ struct serial_struct;
struct device;
struct gpio_desc;

+/*
+ * Must match with serial_rs485 in include/uapi/linux/serial.h excluding the
+ * padding.
+ */
+struct kserial_rs485 {
+ __u32 flags; /* RS485 feature flags */
+ __u32 delay_rts_before_send; /* Delay before send (milliseconds) */
+ __u32 delay_rts_after_send; /* Delay after send (milliseconds) */
+ struct {
+ __u8 addr_recv;
+ __u8 addr_dest;
+ };
+};
+
/**
* struct uart_ops -- interface between serial_core and the driver
*
@@ -447,7 +461,7 @@ struct uart_port {
void (*handle_break)(struct uart_port *);
int (*rs485_config)(struct uart_port *,
struct ktermios *termios,
- struct serial_rs485 *rs485);
+ struct kserial_rs485 *rs485);
int (*iso7816_config)(struct uart_port *,
struct serial_iso7816 *iso7816);
unsigned int irq; /* irq number */
@@ -567,8 +581,8 @@ struct uart_port {
const char *name; /* port name */
struct attribute_group *attr_group; /* port specific attributes */
const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
- struct serial_rs485 rs485;
- struct serial_rs485 rs485_supported; /* Supported mask for serial_rs485 */
+ struct kserial_rs485 rs485;
+ struct kserial_rs485 rs485_supported; /* Supported mask for serial_rs485 */
struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */
struct serial_iso7816 iso7816;
void *private_data; /* generic platform data pointer */
diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
index cea06924b295..95583e99a798 100644
--- a/include/uapi/linux/serial.h
+++ b/include/uapi/linux/serial.h
@@ -112,8 +112,9 @@ struct serial_icounter_struct {
* support. Set with TIOCSRS485 and get with TIOCGRS485 if supported by your
* platform. The set function returns the new state, with any unsupported bits
* reverted appropriately.
+ *
+ * There's kernel counterpart kserial_rs485 of this struct without padding.
*/
-
struct serial_rs485 {
__u32 flags; /* RS485 feature flags */
#define SER_RS485_ENABLED (1 << 0) /* If enabled */
--
2.30.2