[RFC v2 1/6] firmware: generalize reading file contents as a helper

["Luis R. Rodriguez" <mcgrof@do-not-panic.com>]

From: "Luis R. Rodriguez" <mcgrof@suse.com>

We'll want to reuse this same code later in order to
read two separate types of file contents. Although we
can simplify fw_read_file_contents() to do a direct
return we leave a bit of boilerplate code to make the
next changes easier to review. In this case we'll
later extend the firmware specific read to also go
and fetch the signature file when required.

This commit introduces no functional changes.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Seth Forshee <seth.forshee@canonical.com>
Cc: Kyle McMartin <kyle@kernel.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
 drivers/base/firmware_class.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 8c3aa3c..134dd77 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -291,7 +291,8 @@ static const char * const fw_path[] = {
 module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644);
 MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path");
 
-static int fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf)
+static int __read_file_contents(struct file *file,
+				void **dest_buf, size_t *dest_size)
 {
 	int size;
 	char *buf;
@@ -314,14 +315,30 @@ static int fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf)
 	rc = security_kernel_fw_from_file(file, buf, size);
 	if (rc)
 		goto fail;
-	fw_buf->data = buf;
-	fw_buf->size = size;
+
+	*dest_buf = buf;
+	*dest_size = size;
+
 	return 0;
 fail:
 	vfree(buf);
 	return rc;
 }
 
+static int fw_read_file_contents(struct file *file,
+				 struct firmware_buf *fw_buf)
+{
+	int rc;
+
+	rc = __read_file_contents(file,
+				  &fw_buf->data,
+				  &fw_buf->size);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
 static int fw_get_filesystem_firmware(struct device *device,
 				       struct firmware_buf *buf)
 {
-- 
2.3.2.209.gd67f9d5.dirty