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firmware: add firmware_request_nowarn() - load firmware without warnings 

Currently the firmware loader only exposes one silent path for querying
optional firmware, and that is firmware_request_direct(). This function
also disables the sysfs fallback mechanism, which might not always be the
desired behaviour [0].

This patch introduces a variations of request_firmware() that enable the
caller to disable the undesired warning messages but enables the sysfs
fallback mechanism. This is equivalent to adding FW_OPT_NO_WARN to the
old behaviour.

[0]: https://git.kernel.org/linus/c0cc00f250e1

Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
[mcgrof: used the old API calls as the full rename is not done yet, and
 add the caller for when FW_LOADER is disabled, enhance documentation ]
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Andres Rodriguez 2018-05-10 13:08:45 -07:00 committed by Greg Kroah-Hartman
parent 27d5d7dc9a
commit 7dcc01343e
3 changed files with 42 additions and 0 deletions
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5
Documentation/driver-api/firmware/request_firmware.rst
View File

@ -20,6 +20,11 @@ request_firmware
.. kernel-doc:: drivers/base/firmware_loader/main.c
:functions: request_firmware
firmware_request_nowarn
-----------------------
.. kernel-doc:: drivers/base/firmware_loader/main.c
:functions: firmware_request_nowarn
request_firmware_direct
-----------------------
.. kernel-doc:: drivers/base/firmware_loader/main.c

27
drivers/base/firmware_loader/main.c
View File

@ -631,6 +631,33 @@ request_firmware(const struct firmware **firmware_p, const char *name,
}
EXPORT_SYMBOL(request_firmware);
/**
* firmware_request_nowarn() - request for an optional fw module
* @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 request_firmware(), except
* it doesn't produce warning messages when the file is not found.
* The sysfs fallback mechanism is enabled if direct filesystem lookup fails,
* however, however failures to find the firmware file with it are still
* suppressed. It is therefore up to the driver to check for the return value
* of this call and to decide when to inform the users of errors.
**/
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 = _request_firmware(firmware, name, device, NULL, 0,
FW_OPT_UEVENT | FW_OPT_NO_WARN);
module_put(THIS_MODULE);
return ret;
}
EXPORT_SYMBOL_GPL(firmware_request_nowarn);
/**
* request_firmware_direct() - load firmware directly without usermode helper
* @firmware_p: pointer to firmware image

10
include/linux/firmware.h
View File

@ -42,6 +42,8 @@ struct builtin_fw {
#if defined(CONFIG_FW_LOADER) || (defined(CONFIG_FW_LOADER_MODULE) && defined(MODULE))
int request_firmware(const struct firmware **fw, const char *name,
struct device *device);
int firmware_request_nowarn(const struct firmware **fw, const char *name,
struct device *device);
int request_firmware_nowait(
struct module *module, bool uevent,
const char *name, struct device *device, gfp_t gfp, void *context,
@ -59,6 +61,14 @@ static inline int request_firmware(const struct firmware **fw,
{
return -EINVAL;
}
static inline int firmware_request_nowarn(const struct firmware **fw,
const char *name,
struct device *device)
{
return -EINVAL;
}
static inline int request_firmware_nowait(
struct module *module, bool uevent,
const char *name, struct device *device, gfp_t gfp, void *context,