> Now we increases page reference on add_to_page_cache but doesn't decrease it
> in remove_from_page_cache. Such asymmetric makes confusing about
> page reference so that caller should notice it and comment why they
> release page reference. It's not good API.
>
> Long time ago, Hugh tried it[1] but gave up of reason which
> reiser4's drop_page had to unlock the page between removing it from
> page cache and doing the page_cache_release. But now the situation is
> changed. I think at least things in current mainline doesn't have any
> obstacles. The problem is fs or somethings out of mainline.
> If it has done such thing like reiser4, this patch could be a problem but
> they found it when compile time since we remove remove_from_page_cache.
>
> [1]
http://lkml.org/lkml/2004/10/24/140
>
> The series configuration is following as.
>
> [1/7] : This patch introduces new API delete_from_page_cache.
> [2,3,4,5/7] : Change remove_from_page_cache with delete_from_page_cache.
> Intentionally I divide patch per file since someone might have a concern
> about releasing page reference of delete_from_page_cache in
> somecase (ex, truncate.c)
> [6/7] : Remove old API so out of fs can meet compile error when build time
> and can notice it.
> [7/7] : Change __remove_from_page_cache with __delete_from_page_cache, too.
> In this time, I made all-in-one patch because it doesn't change old behavior
> so it has no concern. Just clean up patch.
>
> Minchan Kim (7):
> [1/7] Introduce delete_from_page_cache
> [2/7] fuse: Change remove_from_page_cache
> [3/7] tlbfs: Change remove_from_page_cache
> [4/7] swap: Change remove_from_page_cache
> [5/7] truncate: Change remove_from_page_cache
> [6/7] Good bye remove_from_page_cache
> [7/7] Change __remove_from_page_cache
>
> fs/fuse/dev.c | 3 +--
> fs/hugetlbfs/inode.c | 3 +--
> include/linux/pagemap.h | 4 ++--
> mm/filemap.c | 22 +++++++++++++++++-----
> mm/shmem.c | 3 +--
> mm/truncate.c | 5 ++---
> mm/vmscan.c | 2 +-
> 7 files changed, 25 insertions(+), 17 deletions(-)
