On Fri, 21 Sep 2007 13:48:28 +0200 Peter Zijlstra <[EMAIL PROTECTED]> wrote: > > Followings are moved > > * page_mapping() ... returns swapper_space or address_space a page > > is on. > > (from mm.h) > > * page_index() ... returns position of a page in its inode > > (from mm.h) > > * remove_mapping() ... a safe routine to remove page->mapping from > > page. > > (from swap.h) > > I have two other functions that might want integration with this scheme: > > page_file_mapping() ... returns backing address space > page_file_index() ... returns the index therein > > They are identical to page_mapping_cache() and page_index() for > page cache pages, but they also work on swap cache pages. > > That is, for swapcache pages they return: > > page_file_mapping: > page_swap_info(page)->swap_file->f_mapping > > page_file_index: > swp_offset((swp_offset_t)page_private(page)) > > When a filesystem uses these functions instead of page->mapping and > page->index, it allows passing swap cache pages into the regular > filesystem read/write paths. > Oh, > This is useful for things like swap over NFS, where swap is backed by a > swapfile on a 'regular' filesystem. > Okay, I'll try to add them in the next set.
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