linux-kernel - Re: [PATCH] serial: 8250_fintek: fix the mismatched IRQ mode

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Message-ID: <CAPybu_2BM-Nm02Y6xv-jg0MMaNGuEgmG6=5S3OO3KuwDUPmHMg@mail.gmail.com>
Date:	Mon, 27 Jun 2016 12:25:46 +0200
From:	Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
To:	"Ji-Ze Hong (Peter Hong)" <hpeter@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, jslaby@...e.com,
	Alan Cox <alan@...ux.intel.com>,
	Peter Hurley <peter@...leysoftware.com>,
	PA20 TOM TSAI 蔡宗佑 
	<tom_tsai@...tek.com.tw>, Peter H <peter_hong@...tek.com.tw>,
	linux-serial@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
	"Ji-Ze Hong (Peter Hong)" <hpeter+linux_kernel@...il.com>
Subject: Re: [PATCH] serial: 8250_fintek: fix the mismatched IRQ mode

Hi Peter,. Hi Greg

On Fri, May 27, 2016 at 4:02 AM, Ji-Ze Hong (Peter Hong)
<hpeter@...il.com> wrote:
>  {
>         struct fintek_8250 *pdata;
>         struct fintek_8250 probe_data;
> +       struct irq_data *irq_data = irq_get_irq_data(uart->port.irq);
> +       bool level_mode = irqd_is_level_type(irq_data);

I see a potential problem with this patch:

If irq_get_irq_data fails, it will return NULL, resulting on a
segmentation fault on irqd_is_level_type:



#define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, state_use_accessors)


I believe that we need to add error checks here

>
>         if (find_base_port(&probe_data, uart->port.iobase))
>                 return -ENODEV;
> @@ -192,5 +226,5 @@ int fintek_8250_probe(struct uart_8250_port *uart)
>         uart->port.rs485_config = fintek_8250_rs485_config;
>         uart->port.private_data = pdata;
>
> -       return 0;
> +       return fintek_8250_set_irq_mode(pdata, level_mode);

Also why do not call irq_get_irq_data() and  irqd_is_level_type()
before return? There is no need to do that work if the probe
determines that it is not a fintek chip.


Greg, this is already queued for 4.7.... what shall we do here?


Regards!




-- 
Ricardo Ribalda