On (02/12/18 11:05), Bart Van Assche wrote: [..] > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index ac4740cf74be..cf17626604c2 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -1026,14 +1026,25 @@ static inline int blk_rq_cur_bytes(const struct request *rq) > > extern unsigned int blk_rq_err_bytes(const struct request *rq); > > +/* > + * Variables of type sector_t represent an offset or size that is a multiple of > + * 2**9 bytes. Hence these two constants. > + */ > +#ifndef SECTOR_SHIFT > +enum { SECTOR_SHIFT = 9 }; > +#endif > +#ifndef SECTOR_SIZE > +enum { SECTOR_SIZE = 512 }; > +#endif Shouldn't SECTOR_SIZE depend on SECTOR_SHIFT? 1 << SECTOR_SHIFT -ss