fs: port acl to const mnt_idmap

Convert to const struct mnt_idmap.

A mount's idmapping is immutable. The only thing that is allowed to be
modified afterwards is the reference count and that is hidden behind
mnt_idmap_get() and mnt_idmap_put(). Everything else only ever reads
from the idmapping. This is the same model that struct cred uses and the
idmapping is also rather sensitive.

So make the idmap argument const wherever we can. The conversion is done
from the bottom up so callers can continue to pass a non-const pointer
to a const parameter until the conversion is finished.

No functional changes.

Link: https://patch.msgid.link/20260901-work-idmap-const-v1-11-54ccd48e100b@kernel.org
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Seth Forshee <sforshee@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

3 files changed, 14 insertions, 14 deletions

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 65c9609ec207..30897590258f 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -159,15 +159,15 @@ LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
 	 const char *name)
 LSM_HOOK(int, 0, inode_file_setattr, struct dentry *dentry, struct file_kattr *fa)
 LSM_HOOK(int, 0, inode_file_getattr, struct dentry *dentry, struct file_kattr *fa)
-LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap,
+LSM_HOOK(int, 0, inode_set_acl, const struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *acl_name, struct posix_acl *kacl)
 LSM_HOOK(void, LSM_RET_VOID, inode_post_set_acl, struct dentry *dentry,
 	 const char *acl_name, struct posix_acl *kacl)
-LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap,
+LSM_HOOK(int, 0, inode_get_acl, const struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *acl_name)
-LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap,
+LSM_HOOK(int, 0, inode_remove_acl, const struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *acl_name)
-LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap,
+LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, const struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *acl_name)
 LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry)
 LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap,
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 62d497763e25..7c6cfcae0a9d 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -84,7 +84,7 @@ struct posix_acl *posix_acl_clone(const struct posix_acl *acl, gfp_t flags);
 int posix_acl_chmod(struct mnt_idmap *, struct dentry *, umode_t);
 extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
 		struct posix_acl **);
-int posix_acl_update_mode(struct mnt_idmap *, struct inode *, umode_t *,
+int posix_acl_update_mode(const struct mnt_idmap *, struct inode *, umode_t *,
 			  struct posix_acl **);
 
 int simple_set_acl(struct mnt_idmap *, struct dentry *,
@@ -96,7 +96,7 @@ void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl);
 void forget_cached_acl(struct inode *inode, int type);
 void forget_all_cached_acls(struct inode *inode);
 int posix_acl_valid(struct user_namespace *, const struct posix_acl *);
-int posix_acl_permission(struct mnt_idmap *, struct inode *,
+int posix_acl_permission(const struct mnt_idmap *, struct inode *,
 			 const struct posix_acl *, int);
 
 static inline void cache_no_acl(struct inode *inode)
diff --git a/include/linux/security.h b/include/linux/security.h
index 4598a13657ee..12bc12e243bf 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -430,16 +430,16 @@ int security_inode_getattr(const struct path *path);
 int security_inode_setxattr(struct mnt_idmap *idmap,
 			    struct dentry *dentry, const char *name,
 			    const void *value, size_t size, int flags);
-int security_inode_set_acl(struct mnt_idmap *idmap,
+int security_inode_set_acl(const struct mnt_idmap *idmap,
 			   struct dentry *dentry, const char *acl_name,
 			   struct posix_acl *kacl);
 void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name,
 				 struct posix_acl *kacl);
-int security_inode_get_acl(struct mnt_idmap *idmap,
+int security_inode_get_acl(const struct mnt_idmap *idmap,
 			   struct dentry *dentry, const char *acl_name);
-int security_inode_remove_acl(struct mnt_idmap *idmap,
+int security_inode_remove_acl(const struct mnt_idmap *idmap,
 			      struct dentry *dentry, const char *acl_name);
-void security_inode_post_remove_acl(struct mnt_idmap *idmap,
+void security_inode_post_remove_acl(const struct mnt_idmap *idmap,
 				    struct dentry *dentry,
 				    const char *acl_name);
 void security_inode_post_setxattr(struct dentry *dentry, const char *name,
@@ -1003,7 +1003,7 @@ static inline int security_inode_setxattr(struct mnt_idmap *idmap,
 	return cap_inode_setxattr(dentry, name, value, size, flags);
 }
 
-static inline int security_inode_set_acl(struct mnt_idmap *idmap,
+static inline int security_inode_set_acl(const struct mnt_idmap *idmap,
 					 struct dentry *dentry,
 					 const char *acl_name,
 					 struct posix_acl *kacl)
@@ -1016,21 +1016,21 @@ static inline void security_inode_post_set_acl(struct dentry *dentry,
 					       struct posix_acl *kacl)
 { }
 
-static inline int security_inode_get_acl(struct mnt_idmap *idmap,
+static inline int security_inode_get_acl(const struct mnt_idmap *idmap,
 					 struct dentry *dentry,
 					 const char *acl_name)
 {
 	return 0;
 }
 
-static inline int security_inode_remove_acl(struct mnt_idmap *idmap,
+static inline int security_inode_remove_acl(const struct mnt_idmap *idmap,
 					    struct dentry *dentry,
 					    const char *acl_name)
 {
 	return 0;
 }
 
-static inline void security_inode_post_remove_acl(struct mnt_idmap *idmap,
+static inline void security_inode_post_remove_acl(const struct mnt_idmap *idmap,
 						  struct dentry *dentry,
 						  const char *acl_name)
 { }