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Date:   Mon, 30 Nov 2020 12:37:58 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     Christoph Hellwig <hch@lst.de>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
        Namjae Jeon <linkinjeon@kernel.org>,
        linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [PATCH] posix_acl.h: define missing ACL functions on
 non-posix-acl build
Message-ID: <X8RpFo+5m1i4L5Gn@jagdpanzerIV.localdomain>
References: <20201130014404.36904-1-sergey.senozhatsky@gmail.com>
 <5b015b83-f183-526a-94e7-029f4c98b30b@infradead.org>
 <X8Rj0s/Emv9Qmv3d@jagdpanzerIV.localdomain>
 <X8RkVIxou1D1YfEb@jagdpanzerIV.localdomain>
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In-Reply-To: <X8RkVIxou1D1YfEb@jagdpanzerIV.localdomain>
Precedence: bulk

A quick question, shouldn't there be dummy definitions for
the EXPORT_SYMBOL-s? So that external modules can be modprobed
and used.

Some of posix_acl exported symbols have dummy definitions,
others don't.

E.g. posix_acl_create() is exported symbol and it's defined for
both FS_POSIX_ACL and !FS_POSIX_ACL. While exported set_posix_acl()
is defined only for FS_POSIX_ACL config.

---

diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 90797f1b421d..8a6c77a69761 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -59,19 +59,19 @@ posix_acl_release(struct posix_acl *acl)
 
 /* posix_acl.c */
 
+extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
+
+extern struct posix_acl *get_posix_acl(struct inode *, int);
+
+#ifdef CONFIG_FS_POSIX_ACL
 extern void posix_acl_init(struct posix_acl *, int);
 extern struct posix_acl *posix_acl_alloc(int, gfp_t);
-extern int posix_acl_valid(struct user_namespace *, const struct posix_acl *);
-extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
-extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
 extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
+extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
 extern int __posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
 extern int __posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
-
-extern struct posix_acl *get_posix_acl(struct inode *, int);
 extern int set_posix_acl(struct inode *, int, struct posix_acl *);
-
-#ifdef CONFIG_FS_POSIX_ACL
+extern int posix_acl_valid(struct user_namespace *, const struct posix_acl *);
 extern int posix_acl_chmod(struct inode *, umode_t);
 extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
 		struct posix_acl **);
@@ -91,18 +91,61 @@ static inline void cache_no_acl(struct inode *inode)
 	inode->i_acl = NULL;
 	inode->i_default_acl = NULL;
 }
+
+struct posix_acl *get_acl(struct inode *inode, int type);
 #else
+static inline void posix_acl_init(struct posix_acl *, int)
+{
+}
+
+static inline struct posix_acl *posix_acl_alloc(int, gfp_t)
+{
+	return NULL;
+}
+
+static inline int posix_acl_valid(struct user_namespace *,
+				  const struct posix_acl *)
+{
+	return 0;
+}
+
+static inline int posix_acl_equiv_mode(const struct posix_acl *, umode_t *)
+{
+	return 0;
+}
+
+static inline struct posix_acl *posix_acl_from_mode(umode_t, gfp_t)
+{
+	return NULL;
+}
+
 static inline int posix_acl_chmod(struct inode *inode, umode_t mode)
 {
 	return 0;
 }
 
+static inline int set_posix_acl(struct inode *, int, struct posix_acl *)
+{
+	return 0;
+}
+
 #define simple_set_acl		NULL
 
 static inline int simple_acl_create(struct inode *dir, struct inode *inode)
 {
 	return 0;
 }
+
+static inline int __posix_acl_create(struct posix_acl **, gfp_t, umode_t *)
+{
+	return 0;
+}
+
+static inline int __posix_acl_chmod(struct posix_acl **, gfp_t, umode_t)
+{
+	return 0;
+}
+
 static inline void cache_no_acl(struct inode *inode)
 {
 }
@@ -117,8 +160,38 @@ static inline int posix_acl_create(struct inode *inode, umode_t *mode,
 static inline void forget_all_cached_acls(struct inode *inode)
 {
 }
+
+static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
+{
+	return NULL;
+}
+
+static inline struct posix_acl *get_cached_acl_rcu(struct inode *inode,
+						   int type)
+{
+	return NULL;
+}
+
+static inline void set_cached_acl(struct inode *inode, int type,
+				  struct posix_acl *acl)
+{
+}
+
+static inline void forget_cached_acl(struct inode *inode, int type)
+{
+}
+
+static inline struct posix_acl *get_acl(struct inode *inode, int type)
+{
+	return NULL;
+}
+
+static inline int posix_acl_update_mode(struct inode *, umode_t *,
+					struct posix_acl **)
+{
+	return 0;
+}
 #endif /* CONFIG_FS_POSIX_ACL */
 
-struct posix_acl *get_acl(struct inode *inode, int type);
 
 #endif  /* __LINUX_POSIX_ACL_H */