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    page_writeback: revive cancel_dirty_page() in a restricted form · 11f81bec
    Tejun Heo 提交于
    cancel_dirty_page() had some issues and b9ea2515 ("page_writeback:
    clean up mess around cancel_dirty_page()") replaced it with
    account_page_cleaned() which makes the caller responsible for clearing
    the dirty bit; unfortunately, the planned changes for cgroup writeback
    support requires synchronization between dirty bit manipulation and
    stat updates.  While we can open-code such synchronization in each
    account_page_cleaned() callsite, that's gonna be unnecessarily awkward
    and verbose.
    
    This patch revives cancel_dirty_page() but in a more restricted form.
    All it does is TestClearPageDirty() followed by account_page_cleaned()
    invocation if the page was dirty.  This helper covers all
    account_page_cleaned() usages except for __delete_from_page_cache()
    which is a special case anyway and left alone.  As this leaves no
    module user for account_page_cleaned(), EXPORT_SYMBOL() is dropped
    from it.
    
    This patch just revives cancel_dirty_page() as a trivial wrapper to
    replace equivalent usages and doesn't introduce any functional
    changes.
    Signed-off-by: NTejun Heo <tj@kernel.org>
    Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
    Signed-off-by: NJens Axboe <axboe@fb.com>
    11f81bec
buffer.c 88.6 KB