linux-kernel - Re: [PATCH v2 1/3] firmware: Introduce request_firmware

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Date:	Mon, 11 Nov 2013 16:34:26 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Takashi Iwai <tiwai@...e.de>
Cc:	linux-kernel@...r.kernel.org, Prarit Bhargava <prarit@...hat.com>,
	Ming Lei <ming.lei@...onical.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	x86@...nel.org, amd64-microcode@...64.org
Subject: Re: [PATCH v2 1/3] firmware: Introduce request_firmware_direct()

On Mon, Nov 11, 2013 at 04:21:16PM +0100, Takashi Iwai wrote:
> When CONFIG_FW_LOADER_USER_HELPER is set, request_firmware() falls
> back to the usermode helper for loading via udev when the direct
> loading fails.  But the recent udev takes way too long timeout (60
> seconds) for non-existing firmware.  This is unacceptable for the
> drivers like microcode loader where they load firmwares optionally,
> i.e. it's no error even if no requested file exists.
> 
> This patch provides a new helper function, request_firmware_direct().
> It behaves as same as request_firmware() except for that it doesn't
> fall back to usermode helper but returns an error immediately if the
> f/w can't be loaded directly in kernel.
> 
> Without CONFIG_FW_LOADER_USER_HELPER=y, request_firmware_direct() is
> just an alias of request_firmware(), due to obvious reason.
> 
> Tested-by: Prarit Bhargava <prarit@...hat.com>
> Acked-by: Ming Lei <ming.lei@...onical.com>
> Signed-off-by: Takashi Iwai <tiwai@...e.de>
> ---
>  drivers/base/firmware_class.c | 36 +++++++++++++++++++++++++++++++-----
>  include/linux/firmware.h      |  7 +++++++
>  2 files changed, 38 insertions(+), 5 deletions(-)

I like it, the 60 seconds thing has been a senseless PITA for no good
reason. I have always wondered what might change in 60 seconds wrt to us
being able to load the firmware...

> diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> index eb8fb94ae2c5..7f48a6ffb0df 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -1061,7 +1061,7 @@ static int assign_firmware_buf(struct firmware *fw, struct device *device,
>  /* called from request_firmware() and request_firmware_work_func() */
>  static int
>  _request_firmware(const struct firmware **firmware_p, const char *name,
> -		  struct device *device, bool uevent, bool nowait)
> +		  struct device *device, bool uevent, bool nowait, bool fallback)

Just a nitpick: three boolean args in a row starts to slowly look like a
function from the windoze API. Can we do:

_request_firmware(..., unsigned long flags)

instead and have nice bit flags for that?

That could be a nice cleanup ontop though. Other than that:

Acked-by: Borislav Petkov <bp@...e.de>

for all three.

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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