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Subject: Re: [PATCH] pata_lagacy: Handle failed ATA timing computation in
 opti82c46x_set_piomode
To:     Haonan Li <lihaonan1105@gmail.com>,
        Damien Le Moal <dlemoal@kernel.org>,
        <linux-ide@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <1a0c4378-29b2-43b4-982b-0d92dfb8ed4f@kernel.org>
 <20231018005220.2551586-1-lihaonan1105@gmail.com>
From:   Sergey Shtylyov <s.shtylyov@omp.ru>
Organization: Open Mobile Platform
Message-ID: <8332cf70-1451-6903-562f-1d16e4c243ae@omp.ru>
Date:   Wed, 18 Oct 2023 20:15:25 +0300
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Hello!

On 10/18/23 3:52 AM, Haonan Li wrote:

> The function opti82c46x_set_piomode utilizes the ata_timing_compute()
> to determine the appropriate ATA timings for a given device. However,
> in certain conditions where the ata_timing_find_mode() function does
> not find a valid mode, ata_timing_compute() returns an error (-EINVAL),
> leaving the tp struct uninitialized.

   Looks like it's very common to ignore the result of ata_timing_compute()
in drivers/ata/...
   Mind sharing the "certain conditions"? :-) I don't think the set_piomode()
method can be called by libata itself with an unsupported xfer mode...

> This patch checks the return value of ata_timing_compute() and print
> err message. This avoids any potential use of uninitialized `tp`
> struct in the opti82c46x_set_piomode function.
> 
> Signed-off-by: Haonan Li <lihaonan1105@gmail.com>
[...]

Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>

MBR, Sergey