From: Andres Rodriguez <andresx7@gmail.com>
Date: Thu, 10 May 2018 13:08:45 -0700
Subject: firmware: add firmware_request_nowarn() - load firmware without
 warnings
Git-commit: 7dcc01343e483efda0882456f8361f061a5f416d
Patch-mainline: v4.18-rc1
References: fate#325981

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>
Acked-by: Borislav Petkov <bp@suse.de>
---
 drivers/base/firmware_class.c |   27 +++++++++++++++++++++++++++
 include/linux/firmware.h      |   10 ++++++++++
 2 files changed, 37 insertions(+)

--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1297,6 +1297,33 @@ request_firmware(const struct firmware *
 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
  * @name: name of firmware file
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -41,6 +41,8 @@ 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,
@@ -58,6 +60,14 @@ static inline int request_firmware(const
 {
 	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,