[RFC][PATCHv2 4/4] tty: 8250: switch to uart_port locking helpers

From: Sergey Senozhatsky
Date: Tue Oct 16 2018 - 01:05:15 EST

Next message: Christophe Leroy: "[PATCH v8 2/9] powerpc: Only use task_struct 'cpu' field on SMP"
Previous message: Sergey Senozhatsky: "[RFC][PATCHv2 3/4] serial: introduce uart_port locking helpers"
In reply to: Sergey Senozhatsky: "[RFC][PATCHv2 3/4] serial: introduce uart_port locking helpers"
Next in thread: Peter Zijlstra: "Re: [RFC][PATCHv2 0/4] less deadlock prone serial consoles"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Switch to uart_port_lock macros:

- use uart_port_lock_for_printk()/uart_port_unlock_after_printk() in
serial8250_console_write().

- use uart_port_lock_*()/uart_port_unlock_*() elsewhere.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
drivers/tty/serial/8250/8250_core.c | 8 +--
drivers/tty/serial/8250/8250_dma.c | 4 +-
drivers/tty/serial/8250/8250_port.c | 81 +++++++++++++----------------
3 files changed, 43 insertions(+), 50 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 94f3e1c64490..34fe546260f6 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -268,7 +268,7 @@ static void serial8250_backup_timeout(struct timer_list *t)
unsigned int iir, ier = 0, lsr;
unsigned long flags;

- spin_lock_irqsave(&up->port.lock, flags);
+ uart_port_lock_irqsave(&up->port, flags);

/*
* Must disable interrupts or else we risk racing with the interrupt
@@ -302,7 +302,7 @@ static void serial8250_backup_timeout(struct timer_list *t)
if (up->port.irq)
serial_out(up, UART_IER, ier);

- spin_unlock_irqrestore(&up->port.lock, flags);
+ uart_port_unlock_irqrestore(&up->port, flags);

/* Standard timer interval plus 0.2s to keep the port running */
mod_timer(&up->timer,
@@ -1078,9 +1078,9 @@ void serial8250_unregister_port(int line)
if (uart->em485) {
unsigned long flags;

- spin_lock_irqsave(&uart->port.lock, flags);
+ uart_port_lock_irqsave(&uart->port, flags);
serial8250_em485_destroy(uart);
- spin_unlock_irqrestore(&uart->port.lock, flags);
+ uart_port_unlock_irqrestore(&uart->port, flags);
}

uart_remove_one_port(&serial8250_reg, &uart->port);
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index bfa1a857f3ff..a9255b4e9353 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -22,7 +22,7 @@ static void __dma_tx_complete(void *param)
dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
UART_XMIT_SIZE, DMA_TO_DEVICE);

- spin_lock_irqsave(&p->port.lock, flags);
+ uart_port_lock_irqsave(&p->port, flags);

dma->tx_running = 0;

@@ -39,7 +39,7 @@ static void __dma_tx_complete(void *param)
serial_port_out(&p->port, UART_IER, p->ier);
}

- spin_unlock_irqrestore(&p->port.lock, flags);
+ uart_port_unlock_irqrestore(&p->port, flags);
}

static void __dma_rx_complete(void *param)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index f776b3eafb96..340aecf23dc5 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -790,9 +790,9 @@ static void enable_rsa(struct uart_8250_port *up)
{
if (up->port.type == PORT_RSA) {
if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
- spin_lock_irq(&up->port.lock);
+ uart_port_lock_irq(&up->port);
__enable_rsa(up);
- spin_unlock_irq(&up->port.lock);
+ uart_port_unlock_irq(&up->port);
}
if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
serial_out(up, UART_RSA_FRR, 0);
@@ -812,7 +812,7 @@ static void disable_rsa(struct uart_8250_port *up)

if (up->port.type == PORT_RSA &&
up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
- spin_lock_irq(&up->port.lock);
+ uart_port_lock_irq(&up->port);

mode = serial_in(up, UART_RSA_MSR);
result = !(mode & UART_RSA_MSR_FIFO);
@@ -825,7 +825,7 @@ static void disable_rsa(struct uart_8250_port *up)

if (result)
up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
- spin_unlock_irq(&up->port.lock);
+ uart_port_unlock_irq(&up->port);
}
}
#endif /* CONFIG_SERIAL_8250_RSA */
@@ -1236,7 +1236,7 @@ static void autoconfig(struct uart_8250_port *up)
* We really do need global IRQs disabled here - we're going to
* be frobbing the chips IRQ enable register to see if it exists.
*/
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);

up->capabilities = 0;
up->bugs = 0;
@@ -1275,7 +1275,7 @@ static void autoconfig(struct uart_8250_port *up)
/*
* We failed; there's nothing here
*/
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
DEBUG_AUTOCONF("IER test failed (%02x, %02x) ",
scratch2, scratch3);
goto out;
@@ -1299,7 +1299,7 @@ static void autoconfig(struct uart_8250_port *up)
status1 = serial_in(up, UART_MSR) & 0xF0;
serial8250_out_MCR(up, save_mcr);
if (status1 != 0x90) {
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
DEBUG_AUTOCONF("LOOP test failed (%02x) ",
status1);
goto out;
@@ -1372,7 +1372,7 @@ static void autoconfig(struct uart_8250_port *up)
serial_out(up, UART_IER, 0);

out_lock:
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);

/*
* Check if the device is a Fintek F81216A
@@ -1483,12 +1483,12 @@ static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
p = em485->port;

serial8250_rpm_get(p);
- spin_lock_irqsave(&p->port.lock, flags);
+ uart_port_lock_irqsave(&p->port, flags);
if (em485->active_timer == &em485->stop_tx_timer) {
__do_stop_tx_rs485(p);
em485->active_timer = NULL;
}
- spin_unlock_irqrestore(&p->port.lock, flags);
+ uart_port_unlock_irqrestore(&p->port, flags);
serial8250_rpm_put(p);
return HRTIMER_NORESTART;
}
@@ -1637,12 +1637,12 @@ static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t)
em485 = container_of(t, struct uart_8250_em485, start_tx_timer);
p = em485->port;

- spin_lock_irqsave(&p->port.lock, flags);
+ uart_port_lock_irqsave(&p->port, flags);
if (em485->active_timer == &em485->start_tx_timer) {
__start_tx(&p->port);
em485->active_timer = NULL;
}
- spin_unlock_irqrestore(&p->port.lock, flags);
+ uart_port_unlock_irqrestore(&p->port, flags);
return HRTIMER_NORESTART;
}

@@ -1884,7 +1884,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
if (iir & UART_IIR_NO_INT)
return 0;

- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);

status = serial_port_in(port, UART_LSR);

@@ -1897,7 +1897,7 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE))
serial8250_tx_chars(up);

- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
return 1;
}
EXPORT_SYMBOL_GPL(serial8250_handle_irq);
@@ -1932,9 +1932,9 @@ static int serial8250_tx_threshold_handle_irq(struct uart_port *port)
if ((iir & UART_IIR_ID) == UART_IIR_THRI) {
struct uart_8250_port *up = up_to_u8250p(port);

- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);
serial8250_tx_chars(up);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
}

iir = serial_port_in(port, UART_IIR);
@@ -1949,10 +1949,10 @@ static unsigned int serial8250_tx_empty(struct uart_port *port)

serial8250_rpm_get(up);

- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);
lsr = serial_port_in(port, UART_LSR);
up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);

serial8250_rpm_put(up);

@@ -2025,13 +2025,13 @@ static void serial8250_break_ctl(struct uart_port *port, int break_state)
unsigned long flags;

serial8250_rpm_get(up);
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);
if (break_state == -1)
up->lcr |= UART_LCR_SBC;
else
up->lcr &= ~UART_LCR_SBC;
serial_port_out(port, UART_LCR, up->lcr);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
serial8250_rpm_put(up);
}

@@ -2282,7 +2282,7 @@ int serial8250_do_startup(struct uart_port *port)
* the interrupt is enabled. Delays are necessary to
* allow register changes to become visible.
*/
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);
if (up->port.irqflags & IRQF_SHARED)
disable_irq_nosync(port->irq);

@@ -2298,7 +2298,7 @@ int serial8250_do_startup(struct uart_port *port)

if (port->irqflags & IRQF_SHARED)
enable_irq(port->irq);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);

/*
* If the interrupt is not reasserted, or we otherwise
@@ -2320,7 +2320,7 @@ int serial8250_do_startup(struct uart_port *port)
*/
serial_port_out(port, UART_LCR, UART_LCR_WLEN8);

- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);
if (up->port.flags & UPF_FOURPORT) {
if (!up->port.irq)
up->port.mctrl |= TIOCM_OUT1;
@@ -2367,7 +2367,7 @@ int serial8250_do_startup(struct uart_port *port)
}

dont_test_tx_en:
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);

/*
* Clear the interrupt registers again for luck, and clear the
@@ -2434,17 +2434,17 @@ void serial8250_do_shutdown(struct uart_port *port)
/*
* Disable interrupts from this port
*/
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);
up->ier = 0;
serial_port_out(port, UART_IER, 0);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);

synchronize_irq(port->irq);

if (up->dma)
serial8250_release_dma(up);

- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);
if (port->flags & UPF_FOURPORT) {
/* reset interrupts on the AST Fourport board */
inb((port->iobase & 0xfe0) | 0x1f);
@@ -2453,7 +2453,7 @@ void serial8250_do_shutdown(struct uart_port *port)
port->mctrl &= ~TIOCM_OUT2;

serial8250_set_mctrl(port, port->mctrl);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);

/*
* Disable break condition and FIFOs
@@ -2679,7 +2679,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
* interrupts disabled.
*/
serial8250_rpm_get(up);
- spin_lock_irqsave(&port->lock, flags);
+ uart_port_lock_irqsave(port, flags);

up->lcr = cval; /* Save computed LCR */

@@ -2783,7 +2783,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
serial_port_out(port, UART_FCR, up->fcr); /* set fcr */
}
serial8250_set_mctrl(port, port->mctrl);
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_irqrestore(port, flags);
serial8250_rpm_put(up);

/* Don't rewrite B0 */
@@ -2806,15 +2806,15 @@ void serial8250_do_set_ldisc(struct uart_port *port, struct ktermios *termios)
{
if (termios->c_line == N_PPS) {
port->flags |= UPF_HARDPPS_CD;
- spin_lock_irq(&port->lock);
+ uart_port_lock_irq(port);
serial8250_enable_ms(port);
- spin_unlock_irq(&port->lock);
+ uart_port_unlock_irq(port);
} else {
port->flags &= ~UPF_HARDPPS_CD;
if (!UART_ENABLE_MS(port, termios->c_cflag)) {
- spin_lock_irq(&port->lock);
+ uart_port_lock_irq(port);
serial8250_disable_ms(port);
- spin_unlock_irq(&port->lock);
+ uart_port_unlock_irq(port);
}
}
}
@@ -3252,19 +3252,13 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
struct uart_port *port = &up->port;
unsigned long flags;
unsigned int ier;
- int locked = 1;
+ bool locked;

touch_nmi_watchdog();

serial8250_rpm_get(up);

- if (port->sysrq)
- locked = 0;
- else if (oops_in_progress)
- locked = spin_trylock_irqsave(&port->lock, flags);
- else
- spin_lock_irqsave(&port->lock, flags);
-
+ uart_port_lock_for_printk(port, flags, locked);
/*
* First save the IER then disable the interrupts
*/
@@ -3300,8 +3294,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
if (up->msr_saved_flags)
serial8250_modem_status(up);

- if (locked)
- spin_unlock_irqrestore(&port->lock, flags);
+ uart_port_unlock_after_printk(port, flags, locked);
serial8250_rpm_put(up);
}

--
2.19.1

Next message: Christophe Leroy: "[PATCH v8 2/9] powerpc: Only use task_struct 'cpu' field on SMP"
Previous message: Sergey Senozhatsky: "[RFC][PATCHv2 3/4] serial: introduce uart_port locking helpers"
In reply to: Sergey Senozhatsky: "[RFC][PATCHv2 3/4] serial: introduce uart_port locking helpers"
Next in thread: Peter Zijlstra: "Re: [RFC][PATCHv2 0/4] less deadlock prone serial consoles"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]