Define cleanup handler using facilities from linux/cleanup.h to simplify
error handling in code using firmware loader. This will allow writing code
like this:

int driver_update_firmware(...)
{
	const struct firmware *fw_entry __free(firmware) = NULL;
	int error;

	...
	error = request_firmware(&fw_entry, fw_name, dev);
	if (error) {
		dev_err(dev, "failed to request firmware %s: %d",
			fw_name, error);
		return error;
	}

	error = check_firmware_valid(fw_entry);
	if (error)
		return error;

	guard(mutex)(&instance->lock);

	error = use_firmware(instance, fw);
	if (error)
		return error;

	return 0;
}

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---

If this is acceptable sticking it into an immutable branch would be very
helpful. Thanks!

 include/linux/firmware.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index de7fea3bca51..2035a0d9cc86 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -4,6 +4,7 @@
 
 #include <linux/types.h>
 #include <linux/compiler.h>
+#include <linux/cleanup.h>
 #include <linux/gfp.h>
 
 #define FW_ACTION_NOUEVENT 0
@@ -196,4 +197,6 @@ static inline void firmware_upload_unregister(struct fw_upload *fw_upload)
 
 int firmware_request_cache(struct device *device, const char *name);
 
+DEFINE_FREE(firmware, struct firmware *, release_firmware(_T))
+
 #endif
-- 
2.43.0.381.gb435a96ce8-goog


-- 
Dmitry

On Wed, Jan 17, 2024 at 12:33:07AM -0800, Dmitry Torokhov wrote:
> Define cleanup handler using facilities from linux/cleanup.h to simplify
> error handling in code using firmware loader. This will allow writing code
> like this:
> 
> int driver_update_firmware(...)
> {
> 	const struct firmware *fw_entry __free(firmware) = NULL;
> 	int error;
> 
> 	...
> 	error = request_firmware(&fw_entry, fw_name, dev);
> 	if (error) {
> 		dev_err(dev, "failed to request firmware %s: %d",
> 			fw_name, error);
> 		return error;
> 	}
> 
> 	error = check_firmware_valid(fw_entry);
> 	if (error)
> 		return error;
> 
> 	guard(mutex)(&instance->lock);
> 
> 	error = use_firmware(instance, fw);
> 	if (error)
> 		return error;
> 
> 	return 0;
> }
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Acked-by: Luis Chamberalin <mcgrof@kernel.org>

  Luis