Re: [PATCH 03/12] mm: Methods for teaching filesystems about PG_swapcache pages

On 06/20/2012 05:37 AM, Mel Gorman wrote:

In order to teach filesystems to handle swap cache pages, three new
page functions are introduced:

   pgoff_t page_file_index(struct page *);
   loff_t page_file_offset(struct page *);
   struct address_space *page_file_mapping(struct page *);

page_file_index() - gives the offset of this page in the file in
PAGE_CACHE_SIZE blocks. Like page->index is for mapped pages, this
function also gives the correct index for PG_swapcache pages.

page_file_offset() - uses page_file_index(), so that it will give
the expected result, even for PG_swapcache pages.

page_file_mapping() - gives the mapping backing the actual page;
that is for swap cache pages it will give swap_file->f_mapping.

Signed-off-by: Peter Zijlstra<redacted>
Signed-off-by: Mel Gorman<mgorman@suse.de>

Reviewed-by: Rik van Riel<redacted>

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