[PATCH v2 3/5] binderfs: add extended_error feature entry

[Carlos Llamas <cmllamas@google.com>]

Add extended_error to the binderfs feature list, to help userspace
determine whether the BINDER_GET_EXTENDED_ERROR ioctl is supported by
the binder driver.

Signed-off-by: Carlos Llamas <cmllamas@google.com>
---
 drivers/android/binderfs.c                                | 8 ++++++++
 .../selftests/filesystems/binderfs/binderfs_test.c        | 1 +
 2 files changed, 9 insertions(+)

diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index e3605cdd4335..6c5e94f6cb3a 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -60,6 +60,7 @@ enum binderfs_stats_mode {
 
 struct binder_features {
 	bool oneway_spam_detection;
+	bool extended_error;
 };
 
 static const struct constant_table binderfs_param_stats[] = {
@@ -75,6 +76,7 @@ static const struct fs_parameter_spec binderfs_fs_parameters[] = {
 
 static struct binder_features binder_features = {
 	.oneway_spam_detection = true,
+	.extended_error = true,
 };
 
 static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb)
@@ -615,6 +617,12 @@ static int init_binder_features(struct super_block *sb)
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
 
+	dentry = binderfs_create_file(dir, "extended_error",
+				      &binder_features_fops,
+				      &binder_features.extended_error);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+
 	return 0;
 }
 
diff --git a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
index 0315955ff0f4..9409bb136d95 100644
--- a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
+++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c
@@ -64,6 +64,7 @@ static int __do_binderfs_test(struct __test_metadata *_metadata)
 		device_path[sizeof(P_tmpdir "/binderfs_XXXXXX/") + BINDERFS_MAX_NAME];
 	static const char * const binder_features[] = {
 		"oneway_spam_detection",
+		"extended_error",
 	};
 
 	change_mountns(_metadata);
-- 
2.36.0.464.gb9c8b46e94-goog