From: Jiri Slaby <jirislaby@kernel.org>
To: Thomas Pfaff <tpfaff@pcs.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tty: Remove pointless synchronize_irq() in uart_port_shutdown()
Date: Wed, 11 May 2022 08:21:36 +0200 [thread overview]
Message-ID: <91c006d0-c6ff-71fa-f0c3-22cf1896fc02@kernel.org> (raw)
In-Reply-To: <4fe2d4a1-fc6a-c7fa-d884-5ebd01bebd3@pcs.com>
On 10. 05. 22, 15:54, Thomas Pfaff wrote:
> From: Thomas Pfaff <tpfaff@pcs.com>
>
> Calling synchronize_irq() after free_irq() is pointless, the context to
> the irq is already lost.
> It was noticed while creating the bugfix "genirq: Synchronize interrupt
> thread startup".
That's correct for most drivers. But some drivers don't call free_irq()
in ->shutdown(). So you likely have to move the synchronization to them.
By a quick grep, I found icom, jsm, sccnxp, sifive, sunhv, and sunzilog.
> Signed-off-by: Thomas Pfaff <tpfaff@pcs.com>
> ---
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index 57840cf90388..b76e76e650ba 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1704,12 +1704,6 @@ static void uart_port_shutdown(struct tty_port *port)
> */
> if (uport)
> uport->ops->shutdown(uport);
> -
> - /*
> - * Ensure that the IRQ handler isn't running on another CPU.
> - */
> - if (uport)
> - synchronize_irq(uport->irq);
> }
>
> static int uart_carrier_raised(struct tty_port *port)
>
>
--
js
suse labs
next prev parent reply other threads:[~2022-05-11 6:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-10 13:54 [PATCH] tty: Remove pointless synchronize_irq() in uart_port_shutdown() Thomas Pfaff
2022-05-10 17:44 ` Thomas Gleixner
2022-05-11 6:21 ` Jiri Slaby [this message]
2022-05-11 7:48 ` Thomas Pfaff
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