| Message ID | 20210416140557.25177-4-johan@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | serial: sysrq cleanup and stm32 fixes | expand |
Hi, On 4/16/21 4:05 PM, Johan Hovold wrote: > Use the uart_unlock_and_check_sysrq() helper to defer sysrq processing > until receive processing is done and the port lock has been released. > > This allows cleaning up the console_write() implementation by not having > to work around the recursive sysrq case (by dropping locking completely) > and also makes the console code work with PREEMPT_RT by no longer > relying on local_irq_save(). > > Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Valentin Caron<valentin.caron@foss.st.com> > --- > drivers/tty/serial/stm32-usart.c | 16 ++++++---------- > 1 file changed, 6 insertions(+), 10 deletions(-) > > diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c > index 3524ed2c0c73..24a1dfe7058b 100644 > --- a/drivers/tty/serial/stm32-usart.c > +++ b/drivers/tty/serial/stm32-usart.c > @@ -270,12 +270,12 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool threaded) > } > } > > - if (uart_handle_sysrq_char(port, c)) > + if (uart_prepare_sysrq_char(port, c)) > continue; > uart_insert_char(port, sr, USART_SR_ORE, c, flag); > } > > - spin_unlock(&port->lock); > + uart_unlock_and_check_sysrq(port); > > tty_flip_buffer_push(tport); > } > @@ -1430,13 +1430,10 @@ static void stm32_usart_console_write(struct console *co, const char *s, > u32 old_cr1, new_cr1; > int locked = 1; > > - local_irq_save(flags); > - if (port->sysrq) > - locked = 0; > - else if (oops_in_progress) > - locked = spin_trylock(&port->lock); > + if (oops_in_progress) > + locked = spin_trylock_irqsave(&port->lock, flags); > else > - spin_lock(&port->lock); > + spin_lock_irqsave(&port->lock, flags); > > /* Save and disable interrupts, enable the transmitter */ > old_cr1 = readl_relaxed(port->membase + ofs->cr1); > @@ -1450,8 +1447,7 @@ static void stm32_usart_console_write(struct console *co, const char *s, > writel_relaxed(old_cr1, port->membase + ofs->cr1); > > if (locked) > - spin_unlock(&port->lock); > - local_irq_restore(flags); > + spin_unlock_irqrestore(&port->lock, flags); > } > > static int stm32_usart_console_setup(struct console *co, char *options)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 3524ed2c0c73..24a1dfe7058b 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -270,12 +270,12 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool threaded) } } - if (uart_handle_sysrq_char(port, c)) + if (uart_prepare_sysrq_char(port, c)) continue; uart_insert_char(port, sr, USART_SR_ORE, c, flag); } - spin_unlock(&port->lock); + uart_unlock_and_check_sysrq(port); tty_flip_buffer_push(tport); } @@ -1430,13 +1430,10 @@ static void stm32_usart_console_write(struct console *co, const char *s, u32 old_cr1, new_cr1; int locked = 1; - local_irq_save(flags); - if (port->sysrq) - locked = 0; - else if (oops_in_progress) - locked = spin_trylock(&port->lock); + if (oops_in_progress) + locked = spin_trylock_irqsave(&port->lock, flags); else - spin_lock(&port->lock); + spin_lock_irqsave(&port->lock, flags); /* Save and disable interrupts, enable the transmitter */ old_cr1 = readl_relaxed(port->membase + ofs->cr1); @@ -1450,8 +1447,7 @@ static void stm32_usart_console_write(struct console *co, const char *s, writel_relaxed(old_cr1, port->membase + ofs->cr1); if (locked) - spin_unlock(&port->lock); - local_irq_restore(flags); + spin_unlock_irqrestore(&port->lock, flags); } static int stm32_usart_console_setup(struct console *co, char *options)
Use the uart_unlock_and_check_sysrq() helper to defer sysrq processing until receive processing is done and the port lock has been released. This allows cleaning up the console_write() implementation by not having to work around the recursive sysrq case (by dropping locking completely) and also makes the console code work with PREEMPT_RT by no longer relying on local_irq_save(). Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/tty/serial/stm32-usart.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-)