On 8/21/2020 12:11 PM, Coly Li wrote: > 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@xxxxxxxxxx> > > > 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 ? Sorry, I don't fully understand your question. I known that the sector size can be 512 or 4K, and the PAGE_SIZE can be 4K or 64K. So even if sector size is 4K, isn't it greater than 8 for 64K pages? I'm not sure if the question you're asking is the one Matthew Wilcox has answered before: https://www.spinics.net/lists/raid/msg64345.html > > 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] > >
