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From: Johan Hovold <johan@kernel.org>
To: Tian Tao <tiantao6@hisilicon.com>
Cc: gregkh@linuxfoundation.org, jirislaby@kernel.org,
	afaerber@suse.de, manivannan.sadhasivam@linaro.org,
	linux-serial@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tty: serial: replace spin_lock_irqsave by spin_lock in hard IRQ
Date: Fri, 20 Nov 2020 09:23:00 +0100	[thread overview]
Message-ID: <X7d85DKvisjA3nYv@localhost> (raw)
In-Reply-To: <1605776489-16283-1-git-send-email-tiantao6@hisilicon.com>

On Thu, Nov 19, 2020 at 05:01:29PM +0800, Tian Tao wrote:
> The code has been in a irq-disabled context since it is hard IRQ. There
> is no necessity to do it again.
> 
> Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
> ---
>  drivers/tty/serial/owl-uart.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c
> index c149f8c3..472fdaf 100644
> --- a/drivers/tty/serial/owl-uart.c
> +++ b/drivers/tty/serial/owl-uart.c
> @@ -251,10 +251,9 @@ static void owl_uart_receive_chars(struct uart_port *port)
>  static irqreturn_t owl_uart_irq(int irq, void *dev_id)
>  {
>  	struct uart_port *port = dev_id;
> -	unsigned long flags;
>  	u32 stat;
>  
> -	spin_lock_irqsave(&port->lock, flags);
> +	spin_lock(&port->lock);

Same thing here; this will break with forced irq threading (i.e.
"threadirqs") since the console code can still end up being called from
interrupt context.

>  	stat = owl_uart_read(port, OWL_UART_STAT);
>  
> @@ -268,7 +267,7 @@ static irqreturn_t owl_uart_irq(int irq, void *dev_id)
>  	stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP;
>  	owl_uart_write(port, stat, OWL_UART_STAT);
>  
> -	spin_unlock_irqrestore(&port->lock, flags);
> +	spin_unlock(&port->lock);
>  
>  	return IRQ_HANDLED;
>  }

Johan

WARNING: multiple messages have this Message-ID (diff)
From: Johan Hovold <johan@kernel.org>
To: Tian Tao <tiantao6@hisilicon.com>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
	linux-serial@vger.kernel.org, manivannan.sadhasivam@linaro.org,
	jirislaby@kernel.org, afaerber@suse.de,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] tty: serial: replace spin_lock_irqsave by spin_lock in hard IRQ
Date: Fri, 20 Nov 2020 09:23:00 +0100	[thread overview]
Message-ID: <X7d85DKvisjA3nYv@localhost> (raw)
In-Reply-To: <1605776489-16283-1-git-send-email-tiantao6@hisilicon.com>

On Thu, Nov 19, 2020 at 05:01:29PM +0800, Tian Tao wrote:
> The code has been in a irq-disabled context since it is hard IRQ. There
> is no necessity to do it again.
> 
> Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
> ---
>  drivers/tty/serial/owl-uart.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c
> index c149f8c3..472fdaf 100644
> --- a/drivers/tty/serial/owl-uart.c
> +++ b/drivers/tty/serial/owl-uart.c
> @@ -251,10 +251,9 @@ static void owl_uart_receive_chars(struct uart_port *port)
>  static irqreturn_t owl_uart_irq(int irq, void *dev_id)
>  {
>  	struct uart_port *port = dev_id;
> -	unsigned long flags;
>  	u32 stat;
>  
> -	spin_lock_irqsave(&port->lock, flags);
> +	spin_lock(&port->lock);

Same thing here; this will break with forced irq threading (i.e.
"threadirqs") since the console code can still end up being called from
interrupt context.

>  	stat = owl_uart_read(port, OWL_UART_STAT);
>  
> @@ -268,7 +267,7 @@ static irqreturn_t owl_uart_irq(int irq, void *dev_id)
>  	stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP;
>  	owl_uart_write(port, stat, OWL_UART_STAT);
>  
> -	spin_unlock_irqrestore(&port->lock, flags);
> +	spin_unlock(&port->lock);
>  
>  	return IRQ_HANDLED;
>  }

Johan

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  parent reply	other threads:[~2020-11-20  8:23 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-19  9:01 [PATCH] tty: serial: replace spin_lock_irqsave by spin_lock in hard IRQ Tian Tao
2020-11-19  9:01 ` Tian Tao
2020-11-19  9:03 ` Jiri Slaby
2020-11-19  9:03   ` Jiri Slaby
2020-11-20  8:23 ` Johan Hovold [this message]
2020-11-20  8:23   ` Johan Hovold
2020-11-20 11:25   ` tiantao (H)
2020-11-20 11:25     ` tiantao (H)
2020-11-20 12:49     ` Johan Hovold
2020-11-20 12:49       ` Johan Hovold
2020-11-20 20:00       ` David Laight
2020-11-20 20:00         ` David Laight
2020-11-21 15:17         ` Johan Hovold
2020-11-21 15:17           ` Johan Hovold

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