On Mon, Mar 22, 2010 at 04:39:37PM +1100, Nick Piggin wrote: > It's ugly and lazy that we do these default aops in case it has not > been filled in by the filesystem. > > A NULL operation should always mean either: we don't support the > operation; we don't require any action; or a bug in the filesystem, > depending on the context. > > In practice, if we get rid of these fallbacks, it will be clearer > what operations are used by a given address_space_operations struct, > reduce branches, reduce #if BLOCK ifdefs, and should allow us to get > rid of all the buffer_head knowledge from core mm and fs code. > > We could add a patch like this which spits out a recipe for how to fix > up filesystems and get them all converted quite easily. Um. Seeing that part of that is for methods absent in mainline (->release(), ->sync()), I'd say that making it mandatory at that point is a bad idea. As for the rest... We have 90 instances of address_space_operations in the kernel. Out of those: 28 have ->releasepage != NULL 27 have ->set_page_dirty != NULL 25 have ->invalidatepage != NULL So I'm not even sure that adding that much boilerplate makes sense. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>