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Message-ID: <CACVXFVPpmdXJV2CC-U=bsA820VD42i2-OqBfNfTPPaMergu8TQ@mail.gmail.com>
Date: Thu, 5 Jun 2014 20:18:08 +0800
From: Ming Lei <ming.lei@...onical.com>
To: Takashi Iwai <tiwai@...e.de>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Tom Gundersen <teg@...m.no>,
Abhay Salunke <Abhay_Salunke@...l.com>,
Stefan Roese <sr@...x.de>, Arnd Bergmann <arnd@...db.de>,
Kay Sievers <kay@...y.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] firmware loader: allow disabling of udev as firmware loader
On Wed, Jun 4, 2014 at 11:48 PM, Takashi Iwai <tiwai@...e.de> wrote:
> [The patch was originally proposed by Tom Gundersen, and rewritten
> afterwards by me; most of changelogs below borrowed from Tom's
> original patch -- tiwai]
>
> Currently (at least) the dell-rbu driver selects FW_LOADER_USER_HELPER,
> which means that distros can't really stop loading firmware through
> udev without breaking other users (though some have).
>
> Ideally we would remove/disable the udev firmware helper in both the
> kernel and in udev, but if we were to disable it in udev and not the
> kernel, the result would be (seemingly) hung kernels as no one would
> be around to cancel firmware requests.
>
> This patch allows udev firmware loading to be disabled while still
> allowing non-udev firmware loading, as done by the dell-rbu driver, to
> continue working. This is achieved by only using the fallback
> mechanism when the uevent is suppressed.
>
> The patch renames the user-selectable Kconfig from FW_LOADER_USER_HELPER
> to FW_LOADER_USER_HELPER_FALLBACK, and the former is reverse-selected
> by the latter or the drivers that need userhelper like dell-rbu.
>
> Also, the "default y" is removed together with this change, since it's
> been deprecated in udev upstream, thus rather better to disable it
> nowadays.
>
> Tested with
> FW_LOADER_USER_HELPER=n
> LATTICE_ECP3_CONFIG=y
> DELL_RBU=y
> and udev without the firmware loading support, but I don't have the
> hardware to test the lattice/dell drivers, so additional testing would
> be appreciated.
>
> Reviewed-by: Tom Gundersen <teg@...m.no>
> Cc: Ming Lei <ming.lei@...onical.com>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Abhay Salunke <Abhay_Salunke@...l.com>
> Cc: Stefan Roese <sr@...x.de>
> Cc: Arnd Bergmann <arnd@...db.de>
> Cc: Kay Sievers <kay@...y.org>
> Signed-off-by: Takashi Iwai <tiwai@...e.de>
> ---
> drivers/base/Kconfig | 10 ++++++++--
> drivers/base/firmware_class.c | 15 ++++++++++-----
> include/linux/firmware.h | 2 +-
> 3 files changed, 19 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 8fa8deab6449..d0bb32e4c416 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -144,15 +144,21 @@ config EXTRA_FIRMWARE_DIR
> some other directory containing the firmware files.
>
> config FW_LOADER_USER_HELPER
> + bool
> +
> +config FW_LOADER_USER_HELPER_FALLBACK
> bool "Fallback user-helper invocation for firmware loading"
> depends on FW_LOADER
> - default y
> + select FW_LOADER_USER_HELPER
> help
> This option enables / disables the invocation of user-helper
> (e.g. udev) for loading firmware files as a fallback after the
> direct file loading in kernel fails. The user-mode helper is
> no longer required unless you have a special firmware file that
> - resides in a non-standard path.
> + resides in a non-standard path. Moreover, the udev support has
> + been deprecated upstream.
> +
> + If you are unsure about this, say N here.
It may be safer to say Y here for fallback if not sure.
>
> config DEBUG_DRIVER
> bool "Driver Core verbose debug messages"
> diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> index d276e33880be..46ea5f4c3bb5 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -100,9 +100,14 @@ static inline long firmware_loading_timeout(void)
> #define FW_OPT_UEVENT (1U << 0)
> #define FW_OPT_NOWAIT (1U << 1)
> #ifdef CONFIG_FW_LOADER_USER_HELPER
> -#define FW_OPT_FALLBACK (1U << 2)
> +#define FW_OPT_USERHELPER (1U << 2)
> #else
> -#define FW_OPT_FALLBACK 0
> +#define FW_OPT_USERHELPER 0
> +#endif
> +#ifdef CONFIG_FW_LOADER_USER_HELPER_FALLBACK
> +#define FW_OPT_FALLBACK FW_OPT_USERHELPER
> +#else
> +#define FW_OPT_FALLBACK 0
> #endif
>
> struct firmware_cache {
> @@ -1111,7 +1116,7 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
>
> ret = fw_get_filesystem_firmware(device, fw->priv);
> if (ret) {
> - if (opt_flags & FW_OPT_FALLBACK) {
> + if (opt_flags & FW_OPT_USERHELPER) {
> dev_warn(device,
> "Direct firmware load failed with error %d\n",
> ret);
> @@ -1171,7 +1176,7 @@ request_firmware(const struct firmware **firmware_p, const char *name,
> }
> EXPORT_SYMBOL(request_firmware);
>
> -#ifdef CONFIG_FW_LOADER_USER_HELPER
> +#ifdef CONFIG_FW_LOADER_USER_HELPER_FALLBACK
> /**
> * request_firmware: - load firmware directly without usermode helper
> * @firmware_p: pointer to firmware image
> @@ -1277,7 +1282,7 @@ request_firmware_nowait(
> fw_work->context = context;
> fw_work->cont = cont;
> fw_work->opt_flags = FW_OPT_NOWAIT | FW_OPT_FALLBACK |
> - (uevent ? FW_OPT_UEVENT : 0);
> + (uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);
>
> if (!try_module_get(module)) {
> kfree(fw_work);
> diff --git a/include/linux/firmware.h b/include/linux/firmware.h
> index 59529330efd6..67e5b801af0c 100644
> --- a/include/linux/firmware.h
> +++ b/include/linux/firmware.h
> @@ -68,7 +68,7 @@ static inline void release_firmware(const struct firmware *fw)
>
> #endif
>
> -#ifdef CONFIG_FW_LOADER_USER_HELPER
> +#ifdef CONFIG_FW_LOADER_USER_HELPER_FALLBACK
> int request_firmware_direct(const struct firmware **fw, const char *name,
> struct device *device);
> #else
> --
> 1.9.3
>
> --
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