linux-kernel - Re: [PATCH] clk: Fix a missing check on regmap_bulk

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Message-ID: <154706014175.15366.2565561612277733965@swboyd.mtv.corp.google.com>
Date:   Wed, 09 Jan 2019 10:55:41 -0800
From:   Stephen Boyd <sboyd@...nel.org>
To:     pakki001@....edu
Cc:     kjlu@....edu, Marek Vasut <marek.vasut@...il.com>,
        Michael Turquette <mturquette@...libre.com>,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clk: Fix a missing check on regmap_bulk_read

Quoting Aditya Pakki (2018-12-24 11:00:32)
> Currently, vc5_pll_recalc_rate() may produce incorrect output when
> regmap_bulk_read() fails. The fix checks the return value of the
> latter function and returns 0 in case of failure.
> 
> Signed-off-by: Aditya Pakki <pakki001@....edu>
> ---
>  drivers/clk/clk-versaclock5.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
> index decffb3826ec..cd76a893c594 100644
> --- a/drivers/clk/clk-versaclock5.c
> +++ b/drivers/clk/clk-versaclock5.c
> @@ -413,7 +413,8 @@ static unsigned long vc5_pll_recalc_rate(struct clk_hw *hw,
>         u32 div_int, div_frc;
>         u8 fb[5];
>  
> -       regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
> +       if (regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5))
> +               return 0;

There are a bunch of other regmap_*() APIs in here that "could fail".
Why has this one been chosen but the other ones not?