Re: [PATCH 0/5] export __clear_page_buffers to cleanup code

[Matthew Wilcox <willy@infradead.org>]

On Sun, Apr 19, 2020 at 12:51:18AM +0200, Guoqing Jiang wrote:
> When reading md code, I find md-bitmap.c copies __clear_page_buffers from
> buffer.c, and after more search, seems there are some places in fs could
> use this function directly. So this patchset tries to export the function
> and use it to cleanup code.

OK, I see why you did this, but there are a couple of problems with it.

One is just a sequencing problem; between exporting __clear_page_buffers()
and removing it from the md code, the md code won't build.

More seriously, most of this code has nothing to do with buffers.  It
uses page->private for its own purposes.

What I would do instead is add:

clear_page_private(struct page *page)
{
	ClearPagePrivate(page);
	set_page_private(page, 0);
	put_page(page);
}

to include/linux/mm.h, then convert all callers of __clear_page_buffers()
to call that instead.