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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 1 Mar 2024 22:45:30 +0100
Subject: [PATCH 17/18] serial: pch: Remove eg20t_port::lock.
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz
The struct eg20t_port has a spinlock_t which is used for locking while
access I/O of the device. Then there is the uart_portlock which is
sometimes and nests within eg20t_port's lock.
The uart_port lock is not used while using the struct in
pch_uart_hal_read() which might be okay. Then both locks are used in
pch_console_write() which looks odd especially the double try_lock part.
All in all it looks like the uart_port's lock could replace eg20t_port's
lock and simplify the code.
Remove eg20t_port::lock and use uart_port's lock for the lock scope.
Link: https://lore.kernel.org/r/20240301215246.891055-18-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/tty/serial/pch_uart.c | 26 ++++++--------------------
1 file changed, 6 insertions(+), 20 deletions(-)
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -237,9 +237,6 @@ struct eg20t_port {
#define IRQ_NAME_SIZE 17
char irq_name[IRQ_NAME_SIZE];
-
- /* protect the eg20t_port private structure and io access to membase */
- spinlock_t lock;
};
/**
@@ -1013,7 +1010,7 @@ static irqreturn_t pch_uart_interrupt(in
int next = 1;
u8 msr;
- spin_lock(&priv->lock);
+ uart_port_lock(&priv->port);
handled = 0;
while (next) {
iid = pch_uart_hal_get_iid(priv);
@@ -1073,7 +1070,7 @@ static irqreturn_t pch_uart_interrupt(in
handled |= (unsigned int)ret;
}
- spin_unlock(&priv->lock);
+ uart_port_unlock(&priv->port);
return IRQ_RETVAL(handled);
}
@@ -1184,9 +1181,9 @@ static void pch_uart_break_ctl(struct ua
unsigned long flags;
priv = container_of(port, struct eg20t_port, port);
- spin_lock_irqsave(&priv->lock, flags);
+ uart_port_lock_irqsave(&priv->port, &flags);
pch_uart_hal_set_break(priv, ctl);
- spin_unlock_irqrestore(&priv->lock, flags);
+ uart_port_unlock_irqrestore(&priv->port, flags);
}
/* Grab any interrupt resources and initialise any low level driver state. */
@@ -1336,8 +1333,7 @@ static void pch_uart_set_termios(struct
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
- spin_lock_irqsave(&priv->lock, flags);
- uart_port_lock(port);
+ uart_port_lock_irqsave(port, &flags);
uart_update_timeout(port, termios->c_cflag, baud);
rtn = pch_uart_hal_set_line(priv, baud, parity, bits, stb);
@@ -1350,8 +1346,7 @@ static void pch_uart_set_termios(struct
tty_termios_encode_baud_rate(termios, baud, baud);
out:
- uart_port_unlock(port);
- spin_unlock_irqrestore(&priv->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
}
static const char *pch_uart_type(struct uart_port *port)
@@ -1555,7 +1550,6 @@ pch_console_write(struct console *co, co
{
struct eg20t_port *priv;
unsigned long flags;
- int priv_locked = 1;
int port_locked = 1;
u8 ier;
@@ -1565,15 +1559,11 @@ pch_console_write(struct console *co, co
local_irq_save(flags);
if (priv->port.sysrq) {
- /* call to uart_handle_sysrq_char already took the priv lock */
- priv_locked = 0;
/* serial8250_handle_port() already took the port lock */
port_locked = 0;
} else if (oops_in_progress) {
- priv_locked = spin_trylock(&priv->lock);
port_locked = uart_port_trylock(&priv->port);
} else {
- spin_lock(&priv->lock);
uart_port_lock(&priv->port);
}
@@ -1595,8 +1585,6 @@ pch_console_write(struct console *co, co
if (port_locked)
uart_port_unlock(&priv->port);
- if (priv_locked)
- spin_unlock(&priv->lock);
local_irq_restore(flags);
}
@@ -1694,8 +1682,6 @@ static struct eg20t_port *pch_uart_init_
pci_enable_msi(pdev);
pci_set_master(pdev);
- spin_lock_init(&priv->lock);
-
iobase = pci_resource_start(pdev, 0);
mapbase = pci_resource_start(pdev, 1);
priv->mapbase = mapbase;
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