> +/* > + * The basic unit of block I/O is a sector. It is used in a number of > contexts > + * in Linux (blk, bio, genhd). The size of one sector is 512 = 2**9 > + * bytes. Variables of type sector_t represent an offset or size that is a > + * multiple of 512 bytes. Hence these two constants. > + */ > +#ifndef SECTOR_SHIFT > +#define SECTOR_SHIFT 9 > +#endif > +#ifndef SECTOR_SIZE > +#define SECTOR_SIZE (1 << SECTOR_SHIFT) > +#endif
While we're at it we really should drop the ifndefs. Otherwise looks good. In fact given that sector_t is in linux/types.h I wonder if these should just move there.
