file_read_actor 1938 include/linux/fs.h extern int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size); file_read_actor 1330 mm/filemap.c do_generic_file_read(filp, ppos, &desc, file_read_actor); file_read_actor 1723 mm/shmem.c do_shmem_file_read(filp, ppos, &desc, file_read_actor);