netdev - Re: [RFC v1 PATCH 1/3] drivers: soc: add support for soc_device_match returning -EPROBE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 19 Apr 2021 10:20:13 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     "Alice Guo (OSS)" <alice.guo@....nxp.com>
Cc:     gregkh@...uxfoundation.org, rafael@...nel.org,
        horia.geanta@....com, aymen.sghaier@....com,
        herbert@...dor.apana.org.au, davem@...emloft.net, tony@...mide.com,
        geert+renesas@...der.be, mturquette@...libre.com, sboyd@...nel.org,
        vkoul@...nel.org, peter.ujfalusi@...il.com, a.hajda@...sung.com,
        narmstrong@...libre.com, robert.foss@...aro.org, airlied@...ux.ie,
        daniel@...ll.ch, khilman@...libre.com, tomba@...nel.org,
        jyri.sarha@....fi, joro@...tes.org, will@...nel.org,
        mchehab@...nel.org, ulf.hansson@...aro.org,
        adrian.hunter@...el.com, kishon@...com, kuba@...nel.org,
        linus.walleij@...aro.org, Roy.Pledge@....com, leoyang.li@....com,
        ssantosh@...nel.org, matthias.bgg@...il.com, edubezval@...il.com,
        j-keerthy@...com, balbi@...nel.org, linux@...sktech.co.nz,
        stern@...land.harvard.edu, wim@...ux-watchdog.org,
        linux@...ck-us.net, linux-kernel@...r.kernel.org,
        linux-crypto@...r.kernel.org, linux-omap@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org, linux-clk@...r.kernel.org,
        dmaengine@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux-foundation.org, linux-media@...r.kernel.org,
        linux-mmc@...r.kernel.org, netdev@...r.kernel.org,
        linux-phy@...ts.infradead.org, linux-gpio@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-staging@...ts.linux.dev,
        linux-mediatek@...ts.infradead.org, linux-pm@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-watchdog@...r.kernel.org,
        Arnd Bergmann <arnd@...db.de>
Subject: Re: [RFC v1 PATCH 1/3] drivers: soc: add support for soc_device_match
 returning -EPROBE_DEFER

Hi Alice,

CC Arnd (soc_device_match() author)

On Mon, Apr 19, 2021 at 6:28 AM Alice Guo (OSS) <alice.guo@....nxp.com> wrote:
> From: Alice Guo <alice.guo@....com>
>
> In i.MX8M boards, the registration of SoC device is later than caam
> driver which needs it. Caam driver needs soc_device_match to provide
> -EPROBE_DEFER when no SoC device is registered and no
> early_soc_dev_attr.

I'm wondering if this is really a good idea: soc_device_match() is a
last-resort low-level check, and IMHO should be made available early on,
so there is no need for -EPROBE_DEFER.

>
> Signed-off-by: Alice Guo <alice.guo@....com>

Thanks for your patch!

> --- a/drivers/base/soc.c
> +++ b/drivers/base/soc.c
> @@ -110,6 +110,7 @@ static void soc_release(struct device *dev)
>  }
>
>  static struct soc_device_attribute *early_soc_dev_attr;
> +static bool soc_dev_attr_init_done = false;

Do you need this variable?

>
>  struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
>  {
> @@ -157,6 +158,7 @@ struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr
>                 return ERR_PTR(ret);
>         }
>
> +       soc_dev_attr_init_done = true;
>         return soc_dev;
>
>  out3:
> @@ -246,6 +248,9 @@ const struct soc_device_attribute *soc_device_match(
>         if (!matches)
>                 return NULL;
>
> +       if (!soc_dev_attr_init_done && !early_soc_dev_attr)

if (!soc_bus_type.p && !early_soc_dev_attr)

> +               return ERR_PTR(-EPROBE_DEFER);
> +
>         while (!ret) {
>                 if (!(matches->machine || matches->family ||
>                       matches->revision || matches->soc_id))

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds