fs: Create sb_encoding() helper

Filesystems that need to deal with the super block encoding need to use
a if IS_ENABLED(CONFIG_UNICODE) around it because this struct member is
not declared otherwise. In order to move this if/endif guards outside of
the filesytem code and make it simpler, create a new function that
returns the s_encoding member of struct super_block if Unicode is
enabled, and return NULL otherwise.

Suggested-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Reviewed-by: Gabriel Krisman Bertazi <gabriel@krisman.be>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>

diff --git a/include/linux/fs.h b/include/linux/fs.h
index d7ab4f96d7051f23246c1a16a2d09b1ffcd2d5de..43b3a7cf6750d3db3e5350908c95bc8a729db41a 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3740,15 +3740,20 @@ static inline bool generic_ci_validate_strict_name(struct inode *dir, struct qst
 }
 #endif
 
-static inline bool sb_has_encoding(const struct super_block *sb)
+static inline struct unicode_map *sb_encoding(const struct super_block *sb)
 {
 #if IS_ENABLED(CONFIG_UNICODE)
-       return !!sb->s_encoding;
+       return sb->s_encoding;
 #else
-       return false;
+       return NULL;
 #endif
 }
 
+static inline bool sb_has_encoding(const struct super_block *sb)
+{
+       return !!sb_encoding(sb);
+}
+
 int may_setattr(struct mnt_idmap *idmap, struct inode *inode,
                unsigned int ia_valid);
 int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);