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From:   Doug Anderson <dianders@chromium.org>
Date:   Mon, 10 Jan 2022 16:51:04 -0800
Message-ID: <CAD=FV=VVzQFK_PwnCXkJ6OK3DcgBnoxmvNG3WXFn30ncdY-E_w@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] ath10k: search for default BDF name provided in DT
To:     Abhishek Kumar <kuabhs@chromium.org>
Cc:     Kalle Valo <kvalo@codeaurora.org>,
        ath10k <ath10k@lists.infradead.org>,
        Rakesh Pillai <pillair@codeaurora.org>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Kalle Valo <kvalo@kernel.org>, netdev <netdev@vger.kernel.org>
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Precedence: bulk

Hi,

On Mon, Jan 10, 2022 at 3:15 PM Abhishek Kumar <kuabhs@chromium.org> wrote:
>
> +int ath10k_core_parse_default_bdf_dt(struct ath10k *ar)
> +{
> +       struct device_node *node;
> +       const char *board_name = NULL;
> +
> +       ar->id.default_bdf[0] = '\0';
> +
> +       node = ar->dev->of_node;
> +       if (!node)
> +               return -ENOENT;
> +
> +       of_property_read_string(node, "qcom,ath10k-default-bdf",
> +                               &board_name);
> +       if (!board_name)
> +               return -ENODATA;
> +
> +       if (strscpy(ar->id.default_bdf,
> +                   board_name, sizeof(ar->id.default_bdf)) < 0)
> +               ath10k_warn(ar,
> +                           "default board name is longer than allocated buffer, board_name: %s; allocated size: %ld\n",
> +                           board_name, sizeof(ar->id.default_bdf));

I suspect, but don't know for sure, that you're going to get another
builder splat here. Just like sizeof() isn't guaranteed to return an
"unsigned int", it's also not guaranteed to return an "unsigned long".
I believe you want %zu. See Documentation/core-api/printk-formats.rst

> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(ath10k_core_parse_default_bdf_dt);

Boy, that function seems like overkill for something that you need
once at init time. ...and I also suspect that the lifetime of the
string returned by of_property_read_string() is valid for as long as
your "of_node" is held and thus probably you could use it directly (it
likely has a longer lifetime than the location you're storing it).

...but I guess it matches the ath10k_core_check_dt() function above
it, so I guess it's fine?

-Doug