RE: [PATCH 1/1] tty: serial: samsung: add spin_lock for interrupt and console_write

From: "Jaewon Kim" <jaewon02.kim@samsung.com>
To: "'Greg Kroah-Hartman'" <gregkh@linuxfoundation.org>
Cc: "'Krzysztof Kozlowski'" <krzk@kernel.org>,
	"'Alim Akhtar'" <alim.akhtar@samsung.com>,
	"'Jiri Slaby'" <jirislaby@kernel.org>,
	<linux-samsung-soc@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-serial@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	"'Chanho Park'" <chanho61.park@samsung.com>
Subject: RE: [PATCH 1/1] tty: serial: samsung: add spin_lock for interrupt and console_write
Date: Wed, 6 Apr 2022 17:39:11 +0900	[thread overview]
Message-ID: <042701d84991$ca50d410$5ef27c30$@samsung.com> (raw)
In-Reply-To: <Yk1NmTdUgMcSIq1O@kroah.com>

Hello 

On 22. 4. 6. 17:21, Greg Kroah-Hartman wrote: 
> On Wed, Apr 06, 2022 at 05:22:16PM +0900, Jaewon Kim wrote:
> > The console_write and IRQ handler can run concurrently.
> > Problems may occurs console_write is continuously executed while the
> > IRQ handler is running.
> >
> > Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
> > ---
> >  drivers/tty/serial/samsung_tty.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> >
> > diff --git a/drivers/tty/serial/samsung_tty.c
> > b/drivers/tty/serial/samsung_tty.c
> > index e1585fbae909..9db479d728b5 100644
> > --- a/drivers/tty/serial/samsung_tty.c
> > +++ b/drivers/tty/serial/samsung_tty.c
> > @@ -2480,12 +2480,24 @@ s3c24xx_serial_console_write(struct console *co, const char *s,
> >  			     unsigned int count)
> >  {
> >  	unsigned int ucon = rd_regl(cons_uart, S3C2410_UCON);
> > +	unsigned long flags;
> > +	bool locked = 1;
> 
> "1" is not a boolean :)

return value of spin_trylock() is 1 or 0.
It seems better to keep it as an int than to change it to bool.
I will return it to int.

Thanks
Jaewon Kim

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