linux-kernel - Re: Re: [PATCH v2] ide: Check for null pointer after calling devm

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Message-Id: <20220107114758.4057401-1-jiasheng@iscas.ac.cn>
Date:   Fri,  7 Jan 2022 19:47:58 +0800
From:   Jiasheng Jiang <jiasheng@...as.ac.cn>
To:     David.Laight@...LAB.COM, damien.lemoal@...nsource.wdc.com,
        davem@...emloft.net
Cc:     linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org, Jiasheng Jiang <jiasheng@...as.ac.cn>
Subject: Re: Re: [PATCH v2] ide: Check for null pointer after calling devm_ioremap

On Fri, Jan 07, 2022 at 05:28:59PM +0800, David Laight wrote:
> That !!alt_base doesn't look right.
> Without looking at the rest of the code maybe:
> 	if (!base && !alt_base)
> may be correct.

Thanks, that's my fault.
I will correct it.

> It also rather makes me wonder about the actual failure return value.
> If devm_ioport_map() returns a 'port number' for inb()/outb() then
> zero is technically a valid value!

That's not right.
The devm_ioport_map() returns NULL if fails and returns non-NULL
pointer if success.
And also we can find in `drivers/ata/pata_platform.c` that it also
use the same way to check the return value from devm_ioport_map().

I will submit a new version to correct my code.

Sincerely thanks,
Jiang