Re: [PATCH 1/1] block: move the PAGE_SECTORS definition into <linux/blkdev.h>

[Coly Li <colyli@suse.de>]

On 2020/8/21 10:03, Zhen Lei wrote:
> There are too many PAGE_SECTORS definitions, and all of them are the
> same. It looks a bit of a mess. So why not move it into <linux/blkdev.h>,
> to achieve a basic and unique definition.
> 
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>


A lazy question about page size > 4KB: currently in bcache code the
sector size is assumed to be 512 sectors, if kernel page > 4KB, it is
possible that PAGE_SECTORS in bcache will be a number > 8 ?

Thanks.

Coly Li


> ---
>  drivers/block/brd.c           | 1 -
>  drivers/block/null_blk_main.c | 1 -
>  drivers/md/bcache/util.h      | 2 --
>  include/linux/blkdev.h        | 5 +++--
>  include/linux/device-mapper.h | 1 -
>  5 files changed, 3 insertions(+), 7 deletions(-)
> 

[snipped]

> diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
> index c029f7443190805..55196e0f37c32c6 100644
> --- a/drivers/md/bcache/util.h
> +++ b/drivers/md/bcache/util.h
> @@ -15,8 +15,6 @@
>  
>  #include "closure.h"
>  
> -#define PAGE_SECTORS		(PAGE_SIZE / 512)
> -
>  struct closure;
>  
>  #ifdef CONFIG_BCACHE_DEBUG
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index bb5636cc17b91a7..b068dfc5f2ef0ab 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -949,11 +949,12 @@ static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
>   * multiple of 512 bytes. Hence these two constants.
>   */
>  #ifndef SECTOR_SHIFT
> -#define SECTOR_SHIFT 9
> +#define SECTOR_SHIFT		9
>  #endif
>  #ifndef SECTOR_SIZE
> -#define SECTOR_SIZE (1 << SECTOR_SHIFT)
> +#define SECTOR_SIZE		(1 << SECTOR_SHIFT)
>  #endif
> +#define PAGE_SECTORS		(PAGE_SIZE / SECTOR_SIZE)
>  
>  /*
>   * blk_rq_pos()			: the current sector
[snipped]