mm: factor out page cache page freeing into a separate function

mm: factor out page cache page freeing into a separate function

Factor out page freeing from delete_from_page_cache() into a separate
function.  We will need to call the same when batching pagecache
deletion operations.

invalidate_complete_page2() and replace_page_cache_page() might want to
call this function as well however they currently don't seem to handle
THPs so it's unnecessary for them to take the hit of checking whether a
page is THP or not.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Jan Kara <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Reviewed-by: Andi Kleen <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>