Re: [PATCH 2/2] net: encx24j600: Fix invalid logic in reading of MISTAT register

[Pavan Chebbi]

On Thu, Dec 1, 2022 at 11:04 PM Valentina Goncharenko
<goncharenko.vp@xxxxxxxxx> wrote:
>
> A loop for reading MISTAT register continues while regmap_read() fails
> and (mistat & BUSY), but if regmap_read() fails a value of mistat is
> undefined.
>
> The patch proposes to check for BUSY flag only when regmap_read()
> succeed. Compile test only.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: d70e53262f5c ("net: Microchip encx24j600 driver")
> Signed-off-by: Valentina Goncharenko <goncharenko.vp@xxxxxxxxx>
> ---
>  drivers/net/ethernet/microchip/encx24j600-regmap.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/microchip/encx24j600-regmap.c b/drivers/net/ethernet/microchip/encx24j600-regmap.c
> index 2e337c7a5773..5693784eec5b 100644
> --- a/drivers/net/ethernet/microchip/encx24j600-regmap.c
> +++ b/drivers/net/ethernet/microchip/encx24j600-regmap.c
> @@ -359,7 +359,7 @@ static int regmap_encx24j600_phy_reg_read(void *context, unsigned int reg,
>                 goto err_out;
>
>         usleep_range(26, 100);
> -       while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) != 0) &&
> +       while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
>                (mistat & BUSY))
>                 cpu_relax();
>
> @@ -397,7 +397,7 @@ static int regmap_encx24j600_phy_reg_write(void *context, unsigned int reg,
>                 goto err_out;
>
>         usleep_range(26, 100);
> -       while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) != 0) &&
> +       while (((ret = regmap_read(ctx->regmap, MISTAT, &mistat)) == 0) &&
>                (mistat & BUSY))
>                 cpu_relax();
>
> --
> 2.25.1
>
Looks OK to me.
Reviewed-by: Pavan Chebbi <pavan.chebbi@xxxxxxxxxxxx>

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