Re: [PATCH] [v2] blkdev: always export SECTOR_SHIFT

From: Christoph Hellwig
Date: Fri Jul 19 2019 - 08:13:42 EST


> +/*
> + * 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.