267 			size_t pgfrom_base, size_t len)  in _shift_data_left_pages()  argument
273 	BUG_ON(pgfrom_base <= pgto_base);  in _shift_data_left_pages()
279 	pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);  in _shift_data_left_pages()
282 	pgfrom_base &= ~PAGE_MASK;  in _shift_data_left_pages()
289 		if (pgfrom_base >= PAGE_SIZE){  in _shift_data_left_pages()
290 			pgfrom_base = 0;  in _shift_data_left_pages()
297 		if (copy > (PAGE_SIZE - pgfrom_base))  in _shift_data_left_pages()
298 			copy = PAGE_SIZE - pgfrom_base;  in _shift_data_left_pages()
303 			memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);  in _shift_data_left_pages()
306 			memmove(vto + pgto_base, vto + pgfrom_base, copy);  in _shift_data_left_pages()
311 		pgfrom_base += copy;  in _shift_data_left_pages()
332 		size_t pgfrom_base, size_t len)  in _shift_data_right_pages()  argument
338 	BUG_ON(pgto_base <= pgfrom_base);  in _shift_data_right_pages()
344 	pgfrom_base += len;  in _shift_data_right_pages()
347 	pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);  in _shift_data_right_pages()
350 	pgfrom_base &= ~PAGE_MASK;  in _shift_data_right_pages()
358 		if (pgfrom_base == 0) {  in _shift_data_right_pages()
359 			pgfrom_base = PAGE_SIZE;  in _shift_data_right_pages()
366 		if (copy > pgfrom_base)  in _shift_data_right_pages()
367 			copy = pgfrom_base;  in _shift_data_right_pages()
369 		pgfrom_base -= copy;  in _shift_data_right_pages()
374 			memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);  in _shift_data_right_pages()
377 			memmove(vto + pgto_base, vto + pgfrom_base, copy);  in _shift_data_right_pages()