fs: port xattr 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-v1-13-54ccd48e100b@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>

5 files changed, 27 insertions, 27 deletions

diff --git a/include/linux/capability.h b/include/linux/capability.h
index c39a2bbefc47..8ab509c4e1ef 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -210,11 +210,11 @@ static inline bool checkpoint_restore_ns_capable_noaudit(struct user_namespace *
 }
 
 /* audit system wants to get cap info from files as well */
-int get_vfs_caps_from_disk(struct mnt_idmap *idmap,
+int get_vfs_caps_from_disk(const struct mnt_idmap *idmap,
 			   const struct dentry *dentry,
 			   struct cpu_vfs_cap_data *cpu_caps);
 
-int cap_convert_nscap(struct mnt_idmap *idmap, struct dentry *dentry,
+int cap_convert_nscap(const struct mnt_idmap *idmap, struct dentry *dentry,
 		      const void **ivalue, size_t size);
 
 #endif /* !_LINUX_CAPABILITY_H */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f815594dd8cb..08166900931a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3399,7 +3399,7 @@ static inline bool generic_ci_validate_strict_name(struct inode *dir,
 
 int may_setattr(const struct mnt_idmap *idmap, struct inode *inode,
 		unsigned int ia_valid);
-int setattr_prepare(struct mnt_idmap *, struct dentry *, struct iattr *);
+int setattr_prepare(const struct mnt_idmap *, struct dentry *, struct iattr *);
 extern int inode_newsize_ok(const struct inode *, loff_t offset);
 void setattr_copy(const struct mnt_idmap *, struct inode *inode,
 		  const struct iattr *attr);
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 30897590258f..e8638f7d2245 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -146,14 +146,14 @@ LSM_HOOK(void, LSM_RET_VOID, inode_post_setattr, struct mnt_idmap *idmap,
 	 struct dentry *dentry, int ia_valid)
 LSM_HOOK(int, 0, inode_getattr, const struct path *path)
 LSM_HOOK(int, 0, inode_xattr_skipcap, const char *name)
-LSM_HOOK(int, 0, inode_setxattr, struct mnt_idmap *idmap,
+LSM_HOOK(int, 0, inode_setxattr, const struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *name, const void *value,
 	 size_t size, int flags)
 LSM_HOOK(void, LSM_RET_VOID, inode_post_setxattr, struct dentry *dentry,
 	 const char *name, const void *value, size_t size, int flags)
 LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name)
 LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry)
-LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap,
+LSM_HOOK(int, 0, inode_removexattr, const struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *name)
 LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
 	 const char *name)
@@ -170,9 +170,9 @@ LSM_HOOK(int, 0, inode_remove_acl, const 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,
+LSM_HOOK(int, 0, inode_killpriv, const struct mnt_idmap *idmap,
 	 struct dentry *dentry)
-LSM_HOOK(int, -EOPNOTSUPP, inode_getsecurity, struct mnt_idmap *idmap,
+LSM_HOOK(int, -EOPNOTSUPP, inode_getsecurity, const struct mnt_idmap *idmap,
 	 struct inode *inode, const char *name, void **buffer, bool alloc)
 LSM_HOOK(int, -EOPNOTSUPP, inode_setsecurity, struct inode *inode,
 	 const char *name, const void *value, size_t size, int flags)
diff --git a/include/linux/security.h b/include/linux/security.h
index 12bc12e243bf..d5832750418a 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -188,8 +188,8 @@ int cap_inode_setxattr(struct dentry *dentry, const char *name,
 int cap_inode_removexattr(const struct mnt_idmap *idmap,
 			  struct dentry *dentry, const char *name);
 int cap_inode_need_killpriv(struct dentry *dentry);
-int cap_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
-int cap_inode_getsecurity(struct mnt_idmap *idmap,
+int cap_inode_killpriv(const struct mnt_idmap *idmap, struct dentry *dentry);
+int cap_inode_getsecurity(const struct mnt_idmap *idmap,
 			  struct inode *inode, const char *name, void **buffer,
 			  bool alloc);
 extern int cap_mmap_addr(unsigned long addr);
@@ -427,7 +427,7 @@ int security_inode_setattr(struct mnt_idmap *idmap,
 void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 				 int ia_valid);
 int security_inode_getattr(const struct path *path);
-int security_inode_setxattr(struct mnt_idmap *idmap,
+int security_inode_setxattr(const struct mnt_idmap *idmap,
 			    struct dentry *dentry, const char *name,
 			    const void *value, size_t size, int flags);
 int security_inode_set_acl(const struct mnt_idmap *idmap,
@@ -446,7 +446,7 @@ void security_inode_post_setxattr(struct dentry *dentry, const char *name,
 				  const void *value, size_t size, int flags);
 int security_inode_getxattr(struct dentry *dentry, const char *name);
 int security_inode_listxattr(struct dentry *dentry);
-int security_inode_removexattr(struct mnt_idmap *idmap,
+int security_inode_removexattr(const struct mnt_idmap *idmap,
 			       struct dentry *dentry, const char *name);
 void security_inode_post_removexattr(struct dentry *dentry, const char *name);
 int security_inode_file_setattr(struct dentry *dentry,
@@ -454,8 +454,8 @@ int security_inode_file_setattr(struct dentry *dentry,
 int security_inode_file_getattr(struct dentry *dentry,
 			      struct file_kattr *fa);
 int security_inode_need_killpriv(struct dentry *dentry);
-int security_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
-int security_inode_getsecurity(struct mnt_idmap *idmap,
+int security_inode_killpriv(const struct mnt_idmap *idmap, struct dentry *dentry);
+int security_inode_getsecurity(const struct mnt_idmap *idmap,
 			       struct inode *inode, const char *name,
 			       void **buffer, bool alloc);
 int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags);
@@ -996,7 +996,7 @@ static inline int security_inode_getattr(const struct path *path)
 	return 0;
 }
 
-static inline int security_inode_setxattr(struct mnt_idmap *idmap,
+static inline int security_inode_setxattr(const struct mnt_idmap *idmap,
 		struct dentry *dentry, const char *name, const void *value,
 		size_t size, int flags)
 {
@@ -1050,7 +1050,7 @@ static inline int security_inode_listxattr(struct dentry *dentry)
 	return 0;
 }
 
-static inline int security_inode_removexattr(struct mnt_idmap *idmap,
+static inline int security_inode_removexattr(const struct mnt_idmap *idmap,
 					     struct dentry *dentry,
 					     const char *name)
 {
@@ -1078,13 +1078,13 @@ static inline int security_inode_need_killpriv(struct dentry *dentry)
 	return cap_inode_need_killpriv(dentry);
 }
 
-static inline int security_inode_killpriv(struct mnt_idmap *idmap,
+static inline int security_inode_killpriv(const struct mnt_idmap *idmap,
 					  struct dentry *dentry)
 {
 	return cap_inode_killpriv(idmap, dentry);
 }
 
-static inline int security_inode_getsecurity(struct mnt_idmap *idmap,
+static inline int security_inode_getsecurity(const struct mnt_idmap *idmap,
 					     struct inode *inode,
 					     const char *name, void **buffer,
 					     bool alloc)
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index 54ac3cbc133f..4cc4257de084 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -47,7 +47,7 @@ struct xattr_handler {
 		   struct inode *inode, const char *name, void *buffer,
 		   size_t size);
 	int (*set)(const struct xattr_handler *,
-		   struct mnt_idmap *idmap, struct dentry *dentry,
+		   const struct mnt_idmap *idmap, struct dentry *dentry,
 		   struct inode *inode, const char *name, const void *buffer,
 		   size_t size, int flags);
 };
@@ -77,25 +77,25 @@ struct xattr {
 };
 
 ssize_t __vfs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
-ssize_t vfs_getxattr(struct mnt_idmap *, struct dentry *, const char *,
+ssize_t vfs_getxattr(const struct mnt_idmap *, struct dentry *, const char *,
 		     void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
-int __vfs_setxattr(struct mnt_idmap *, struct dentry *, struct inode *,
+int __vfs_setxattr(const struct mnt_idmap *, struct dentry *, struct inode *,
 		   const char *, const void *, size_t, int);
-int __vfs_setxattr_noperm(struct mnt_idmap *, struct dentry *,
+int __vfs_setxattr_noperm(const struct mnt_idmap *, struct dentry *,
 			  const char *, const void *, size_t, int);
-int __vfs_setxattr_locked(struct mnt_idmap *, struct dentry *,
+int __vfs_setxattr_locked(const struct mnt_idmap *, struct dentry *,
 			  const char *, const void *, size_t, int,
 			  struct delegated_inode *);
-int vfs_setxattr(struct mnt_idmap *, struct dentry *, const char *,
+int vfs_setxattr(const struct mnt_idmap *, struct dentry *, const char *,
 		 const void *, size_t, int);
-int __vfs_removexattr(struct mnt_idmap *, struct dentry *, const char *);
-int __vfs_removexattr_locked(struct mnt_idmap *, struct dentry *,
+int __vfs_removexattr(const struct mnt_idmap *, struct dentry *, const char *);
+int __vfs_removexattr_locked(const struct mnt_idmap *, struct dentry *,
 			     const char *, struct delegated_inode *);
-int vfs_removexattr(struct mnt_idmap *, struct dentry *, const char *);
+int vfs_removexattr(const struct mnt_idmap *, struct dentry *, const char *);
 
 ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size);
-int vfs_getxattr_alloc(struct mnt_idmap *idmap,
+int vfs_getxattr_alloc(const struct mnt_idmap *idmap,
 		       struct dentry *dentry, const char *name,
 		       char **xattr_value, size_t size, gfp_t flags);