linux-kernel - Re: [PATCH 4/8] firmware: add functions to load firmware without warnings v3

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, 16 Apr 2018 15:52:29 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Andres Rodriguez <andresx7@...il.com>, linux-kernel@...r.kernel.org
Cc:     gregkh@...uxfoundation.org, mcgrof@...nel.org,
        alexdeucher@...il.com, ckoenig.leichtzumerken@...il.com,
        kvalo@...eaurora.org, arend.vanspriel@...adcom.com
Subject: Re: [PATCH 4/8] firmware: add functions to load firmware without
 warnings v3

On 04/16/18 15:24, Andres Rodriguez wrote:
> Currently the firmware loader only exposes one silent path for querying
> optional firmware, and that is firmware_request_direct(). This function
> also disables the fallback path, which might not always be the
> desired behaviour. [0]
> 
> This patch introduces variations of firmware_request() and
> firmware_request_nowait() that enable the caller to disable the
> undesired warning messages. This is equivalent to adding FW_OPT_NO_WARN,
> to the old behaviour.
> 
> v2: add header prototype, use updated opt_flags
> v3: split debug message to separate patch
>     added _nowait variant
>     added documentation
> 
> [0]: https://git.kernel.org/linus/c0cc00f250e1
> 
> Signed-off-by: Andres Rodriguez <andresx7@...il.com>
> ---
>  .../driver-api/firmware/request_firmware.rst       | 13 ++++--
>  drivers/base/firmware_loader/main.c                | 52 ++++++++++++++++++++--
>  include/linux/firmware.h                           |  6 +++
>  3 files changed, 63 insertions(+), 8 deletions(-)

> diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
> index 5baadad3012d..14ded1de84bf 100644
> --- a/drivers/base/firmware_loader/main.c
> +++ b/drivers/base/firmware_loader/main.c
> @@ -631,6 +631,30 @@ firmware_request(const struct firmware **firmware_p, const char *name,
>  }
>  EXPORT_SYMBOL(firmware_request);
>  

Please see/use Documentation/doc-guide/kernel-doc.rst:
  /**
   * function_name() - Brief description of function.
   * @arg1: Describe the first argument.
   * @arg2: Describe the second argument.
   *        One can provide multiple line descriptions
   *        for arguments.
...

> +/**
> + * firmware_request_nowarn: - request for an optional fw module

no ':' above.

> + * @firmware: pointer to firmware image
> + * @name: name of firmware file
> + * @device: device for which firmware is being loaded
> + *
> + * This function is similar in behaviour to firmware_request(), except
> + * it doesn't produce warning messages when the file is not found.
> + **/
> +int
> +firmware_request_nowarn(const struct firmware **firmware, const char *name,
> +			struct device *device)
> +{
> +	int ret;
> +
> +	/* Need to pin this module until return */
> +	__module_get(THIS_MODULE);
> +	ret = _firmware_request(firmware, name, device, NULL, 0,
> +				FW_OPT_UEVENT | FW_OPT_NO_WARN);
> +	module_put(THIS_MODULE);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(firmware_request_nowarn);
> +
>  /**
>   * firmware_request_direct: - load firmware directly without usermode helper

No ':' above.

>   * @firmware_p: pointer to firmware image
> @@ -755,10 +779,11 @@ static void firmware_request_work_func(struct work_struct *work)
>  }
>  
>  /**
> - * firmware_request_nowait - asynchronous version of firmware_request
> + * firmware_request_nowait2 - asynchronous version of firmware_request
>   * @module: module requesting the firmware
>   * @uevent: sends uevent to copy the firmware image if this flag
>   *	is non-zero else the firmware copy must be done manually.
> + * @warn: enable warnings
>   * @name: name of firmware file
>   * @device: device for which firmware is being loaded
>   * @gfp: allocation flags
> @@ -778,8 +803,8 @@ static void firmware_request_work_func(struct work_struct *work)
>   *		- can't sleep at all if @gfp is GFP_ATOMIC.
>   **/
>  int
> -firmware_request_nowait(
> -	struct module *module, bool uevent,
> +firmware_request_nowait2(
> +	struct module *module, bool uevent, bool warn,
>  	const char *name, struct device *device, gfp_t gfp, void *context,
>  	void (*cont)(const struct firmware *fw, void *context))
>  {
> @@ -799,7 +824,8 @@ firmware_request_nowait(
>  	fw_work->context = context;
>  	fw_work->cont = cont;
>  	fw_work->opt_flags = FW_OPT_NOWAIT |
> -		(uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER);
> +		(uevent ? FW_OPT_UEVENT : FW_OPT_USERHELPER) |
> +		(warn ? 0 : FW_OPT_NO_WARN);
>  
>  	if (!uevent && fw_cache_is_setup(device, name)) {
>  		kfree_const(fw_work->name);
> @@ -818,6 +844,24 @@ firmware_request_nowait(
>  	schedule_work(&fw_work->work);
>  	return 0;
>  }
> +EXPORT_SYMBOL_GPL(firmware_request_nowait2);
> +
> +/**
> + * firmware_request_nowait - compatibility version of firmware_request_nowait2
> + *
> + * This is equivalent to calling firmware_request_nowait2 with warnings enabled.
> + *
> + * Refer to firmware_request_nowait2 for further details.
> + **/
> +int
> +firmware_request_nowait(
> +	struct module *module, bool uevent,
> +	const char *name, struct device *device, gfp_t gfp, void *context,
> +	void (*cont)(const struct firmware *fw, void *context))
> +{
> +	return firmware_request_nowait2(module, uevent, true, name, device,
> +					gfp, context, cont);
> +}
>  EXPORT_SYMBOL(firmware_request_nowait);
>  
>  #ifdef CONFIG_PM_SLEEP


-- 
~Randy