int write_swap_page (unsigned long addr, swp_entry_t * loc);
Allocate a new swap entry and 'sync' it. Note we discard -EIO errors. That is an artifact left over from swsusp. It did not check the return of rw_swap_page_sync at all, since most pages written back to swap would return -EIO. This is a partial improvement, since we will at least return other errors, though we need to eventually fix the damn code.