From: Johan Hovold <johan@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
Alexandre Torgue <alexandre.torgue@foss.st.com>,
dillon.minfei@gmail.com, Erwan Le Ray <erwan.leray@foss.st.com>,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
Johan Hovold <johan@kernel.org>
Subject: [PATCH 3/3] serial: stm32: defer sysrq processing
Date: Fri, 16 Apr 2021 16:05:57 +0200 [thread overview]
Message-ID: <20210416140557.25177-4-johan@kernel.org> (raw)
In-Reply-To: <20210416140557.25177-1-johan@kernel.org>
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(-)
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)
--
2.26.3
next prev parent reply other threads:[~2021-04-16 14:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 14:05 [PATCH 0/3] serial: sysrq cleanup and stm32 fixes Johan Hovold
2021-04-16 14:05 ` [PATCH 1/3] serial: do not restore interrupt state in sysrq helper Johan Hovold
2021-04-16 14:05 ` [PATCH 2/3] serial: stm32: fix threaded interrupt handling Johan Hovold
2021-04-16 14:19 ` Johan Hovold
[not found] ` <CAL9mu0KwgOFQfa8ft4rB6+F=KLd1gZLYDvwpAW72zPAFntehVw@mail.gmail.com>
2021-04-16 14:46 ` Johan Hovold
2021-04-22 9:34 ` Valentin CARON - foss
2021-04-16 14:05 ` Johan Hovold [this message]
2021-04-22 9:36 ` [PATCH 3/3] serial: stm32: defer sysrq processing Valentin CARON - foss
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