file: remove __receive_fd()

Honestly, there's little value in having a helper with and without that
int __user *ufd argument. It's just messy and doesn't really give us
anything. Just expose receive_fd() with that argument and get rid of
that helper.

Link: https://lore.kernel.org/r/20231130-vfs-files-fixes-v1-5-e73ca6f4ea83@kernel.orgReviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

drivers/vdpa/vdpa_user/vduse_dev.c

@@ -1157,7 +1157,7 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 			fput(f);
 			break;
 		}
-		ret = receive_fd(f, perm_to_file_flags(entry.perm));
+		ret = receive_fd(f, NULL, perm_to_file_flags(entry.perm));
 		fput(f);
 		break;
 	}

fs/file.c

@@ -1296,7 +1296,7 @@ int replace_fd(unsigned fd, struct file *file, unsigned flags)
 }
 
 /**
- * __receive_fd() - Install received file into file descriptor table
+ * receive_fd() - Install received file into file descriptor table
  * @file: struct file that was received from another process
  * @ufd: __user pointer to write new fd number to
  * @o_flags: the O_* flags to apply to the new fd entry
@@ -1310,7 +1310,7 @@ int replace_fd(unsigned fd, struct file *file, unsigned flags)
  *
  * Returns newly install fd or -ve on error.
  */
-int __receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)
+int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)
 {
 	int new_fd;
 	int error;
@@ -1335,6 +1335,7 @@ int __receive_fd(struct file *file, int __user *ufd, unsigned int o_flags)
 	__receive_sock(file);
 	return new_fd;
 }
+EXPORT_SYMBOL_GPL(receive_fd);
 
 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags)
 {
@@ -1350,12 +1351,6 @@ int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags)
 	return new_fd;
 }
 
-int receive_fd(struct file *file, unsigned int o_flags)
-{
-	return __receive_fd(file, NULL, o_flags);
-}
-EXPORT_SYMBOL_GPL(receive_fd);
-
 static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
 {
 	int err = -EBADF;

include/linux/file.h

@@ -96,10 +96,7 @@ DEFINE_CLASS(get_unused_fd, int, if (_T >= 0) put_unused_fd(_T),
 
 extern void fd_install(unsigned int fd, struct file *file);
 
-extern int __receive_fd(struct file *file, int __user *ufd,
-			unsigned int o_flags);
-
-extern int receive_fd(struct file *file, unsigned int o_flags);
+int receive_fd(struct file *file, int __user *ufd, unsigned int o_flags);
 
 int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
 

include/net/scm.h

@@ -214,7 +214,7 @@ static inline int scm_recv_one_fd(struct file *f, int __user *ufd,
 {
 	if (!ufd)
 		return -EFAULT;
-	return __receive_fd(f, ufd, flags);
+	return receive_fd(f, ufd, flags);
 }
 
 #endif /* __LINUX_NET_SCM_H */

kernel/pid.c

@@ -700,7 +700,7 @@ static int pidfd_getfd(struct pid *pid, int fd)
 	if (IS_ERR(file))
 		return PTR_ERR(file);
 
-	ret = receive_fd(file, O_CLOEXEC);
+	ret = receive_fd(file, NULL, O_CLOEXEC);
 	fput(file);
 
 	return ret;

kernel/seccomp.c

@@ -1072,7 +1072,7 @@ static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd, struct seccomp_kn
 	 */
 	list_del_init(&addfd->list);
 	if (!addfd->setfd)
-		fd = receive_fd(addfd->file, addfd->flags);
+		fd = receive_fd(addfd->file, NULL, addfd->flags);
 	else
 		fd = receive_fd_replace(addfd->fd, addfd->file, addfd->flags);
 	addfd->ret = fd;