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Message-ID: <98c359ba-9563-3da0-d968-ae40cee9d45f@kernel.org>
Date:   Wed, 6 Apr 2022 11:48:56 +0200
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Subject: Re: [PATCH 1/1] tty: serial: samsung: add spin_lock for interrupt and
 console_write
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To:     Jaewon Kim <jaewon02.kim@samsung.com>,
        'Greg Kroah-Hartman' <gregkh@linuxfoundation.org>
Cc:     'Krzysztof Kozlowski' <krzk@kernel.org>,
        'Alim Akhtar' <alim.akhtar@samsung.com>,
        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>
References: <20220406082216.11206-1-jaewon02.kim@samsung.com>
 <CGME20220406081823epcas2p2f7afa27e2402c4fc02c9bee5972bed4f@epcas2p2.samsung.com>
 <20220406082216.11206-2-jaewon02.kim@samsung.com>
 <Yk1NmTdUgMcSIq1O@kroah.com> <042701d84991$ca50d410$5ef27c30$@samsung.com>
From:   Jiri Slaby <jirislaby@kernel.org>
In-Reply-To: <042701d84991$ca50d410$5ef27c30$@samsung.com>
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On 06. 04. 22, 10:39, Jaewon Kim wrote:
> 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.

Hi, no, do not that. Simply use bool/true/false.

thanks,
-- 
js
suse labs