On Sun, Mar 20, 2016 at 09:40:20PM +0300, Kirill A. Shutemov wrote:
> PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago
> with promise that one day it will be possible to implement page cache with
> bigger chunks than PAGE_SIZE.
>
> This promise never materialized. And unlikely will.
>
> We have many places where PAGE_CACHE_SIZE assumed to be equal to
> PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_*
> or PAGE_* constant should be used in a particular case, especially on the
> border between fs and mm.
>
> Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
> breakage to be doable.
>
> Let's stop pretending that pages in page cache are special. They are not.
>
> The changes are pretty straight-forward:
>
> - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
>
> - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
>
> - page_cache_get() -> get_page();
>
> - page_cache_release() -> put_page();
>
> Signed-off-by: Kirill A. Shutemov <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Vishal Verma <[email protected]>
> Cc: Ross Zwisler <[email protected]>
Sure, this seems right. Thanks for making this simpler.
Reviewed-by: Ross Zwisler <[email protected]>
> ---
> drivers/nvdimm/btt.c | 2 +-
> drivers/nvdimm/pmem.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
> index c32cbb593600..f068b6513cd2 100644
> --- a/drivers/nvdimm/btt.c
> +++ b/drivers/nvdimm/btt.c
> @@ -1204,7 +1204,7 @@ static int btt_rw_page(struct block_device *bdev,
> sector_t sector,
> {
> struct btt *btt = bdev->bd_disk->private_data;
>
> - btt_do_bvec(btt, NULL, page, PAGE_CACHE_SIZE, 0, rw, sector);
> + btt_do_bvec(btt, NULL, page, PAGE_SIZE, 0, rw, sector);
> page_endio(page, rw & WRITE, 0);
> return 0;
> }
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index ca5721c306bb..a1a29c711532 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -151,7 +151,7 @@ static int pmem_rw_page(struct block_device *bdev,
> sector_t sector,
> struct pmem_device *pmem = bdev->bd_disk->private_data;
> int rc;
>
> - rc = pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
> + rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, rw, sector);
> if (rw & WRITE)
> wmb_pmem();
>
> --
> 2.7.0
>
