[PATCH v2 1/2] firmware: add nowarn variant of request_firmware_nowait()

[Lucas Stach]

Device drivers with optional firmware may still want to use the
asynchronous firmware loading interface. To avoid printing a
warining into the kernel log when the optional firmware is
absent, add a nowarn variant of this interface.

Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
---
v2: Add missing documentation, as pointed out by 0-day bot.
---
 drivers/base/firmware_loader/main.c | 92 ++++++++++++++++++++---------
 include/linux/firmware.h            | 12 ++++
 2 files changed, 77 insertions(+), 27 deletions(-)

diff --git a/drivers/base/firmware_loader/main.c b/drivers/base/firmware_loader/main.c
index 8e9213b36e31..9fa4ee154147 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -790,34 +790,11 @@ static void request_firmware_work_func(struct work_struct *work)
 	kfree(fw_work);
 }
 
-/**
- * request_firmware_nowait() - asynchronous version of request_firmware
- * @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.
- * @name: name of firmware file
- * @device: device for which firmware is being loaded
- * @gfp: allocation flags
- * @context: will be passed over to @cont, and
- *	@fw may be %NULL if firmware request fails.
- * @cont: function will be called asynchronously when the firmware
- *	request is over.
- *
- *	Caller must hold the reference count of @device.
- *
- *	Asynchronous variant of request_firmware() for user contexts:
- *		- sleep for as small periods as possible since it may
- *		  increase kernel boot time of built-in device drivers
- *		  requesting firmware in their ->probe() methods, if
- *		  @gfp is GFP_KERNEL.
- *
- *		- can't sleep at all if @gfp is GFP_ATOMIC.
- **/
-int
-request_firmware_nowait(
+
+static int _request_firmware_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))
+	void (*cont)(const struct firmware *fw, void *context), bool nowarn)
 {
 	struct firmware_work *fw_work;
 
@@ -835,7 +812,8 @@ request_firmware_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) |
+		(nowarn ? FW_OPT_NO_WARN : 0);
 
 	if (!uevent && fw_cache_is_setup(device, name)) {
 		kfree_const(fw_work->name);
@@ -854,8 +832,68 @@ request_firmware_nowait(
 	schedule_work(&fw_work->work);
 	return 0;
 }
+
+/**
+ * request_firmware_nowait() - asynchronous version of request_firmware
+ * @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.
+ * @name: name of firmware file
+ * @device: device for which firmware is being loaded
+ * @gfp: allocation flags
+ * @context: will be passed over to @cont, and
+ *	@fw may be %NULL if firmware request fails.
+ * @cont: function will be called asynchronously when the firmware
+ *	request is over.
+ *
+ *	Caller must hold the reference count of @device.
+ *
+ *	Asynchronous variant of request_firmware() for user contexts:
+ *		- sleep for as small periods as possible since it may
+ *		  increase kernel boot time of built-in device drivers
+ *		  requesting firmware in their ->probe() methods, if
+ *		  @gfp is GFP_KERNEL.
+ *
+ *		- can't sleep at all if @gfp is GFP_ATOMIC.
+ **/
+int request_firmware_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 _request_firmware_nowait(module, uevent, name, device, gfp,
+					context, cont, false);
+
+}
 EXPORT_SYMBOL(request_firmware_nowait);
 
+/**
+ * request_firmware_nowait_nowarn() - async version of request_firmware_nowarn
+ * @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.
+ * @name: name of firmware file
+ * @device: device for which firmware is being loaded
+ * @gfp: allocation flags
+ * @context: will be passed over to @cont, and
+ *	@fw may be %NULL if firmware request fails.
+ * @cont: function will be called asynchronously when the firmware
+ *	request is over.
+ *
+ * Similar in function to request_firmware_nowait(), but doesn't print a warning
+ * when the firmware file could not be found.
+ */
+int request_firmware_nowait_nowarn(
+	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 _request_firmware_nowait(module, uevent, name, device, gfp,
+					context, cont, true);
+
+}
+EXPORT_SYMBOL(request_firmware_nowait_nowarn);
+
 #ifdef CONFIG_PM_SLEEP
 static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
 
diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index 2dd566c91d44..a6d0bc8273a4 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -48,6 +48,10 @@ int request_firmware_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));
+int request_firmware_nowait_nowarn(
+	struct module *module, bool uevent,
+	const char *name, struct device *device, gfp_t gfp, void *context,
+	void (*cont)(const struct firmware *fw, void *context));
 int request_firmware_direct(const struct firmware **fw, const char *name,
 			    struct device *device);
 int request_firmware_into_buf(const struct firmware **firmware_p,
@@ -77,6 +81,14 @@ static inline int request_firmware_nowait(
 	return -EINVAL;
 }
 
+static inline int request_firmware_nowait_nowarn(
+	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 -EINVAL;
+}
+
 static inline void release_firmware(const struct firmware *fw)
 {
 }
-- 
2.19.1