On Thu, Mar 22, 2018 at 06:16:53PM +0000, Al Viro wrote: > On Thu, Mar 22, 2018 at 06:24:10PM +0100, Christoph Hellwig wrote: > > > -static void aio_complete(struct aio_kiocb *iocb, long res, long res2) > > +static bool aio_complete(struct aio_kiocb *iocb, long res, long res2, > > + unsigned complete_flags) > > Looks like all callers are following that with "if returned true, > fput(something)". Does it really make any sense to keep that struct > file * in different fields?
struct kiocb is used not just for aio, but for our normal read/write_iter APIs, and it is not suitable for poll or fsync. So I can't really find a good way to keep it common except for duplicating it in struct kiocb and strut aio_iocb. But maybe we could pass a struct file argument to aio_complete(). > Wait a sec... What ordering do we want for > * call(s) of ->ki_complete > * call (if any) of ->ki_cancel > * dropping reference to struct file > and what are the expected call chains for all of those? fput must be done exactly once from inside ->ki_complete OR ->ki_cancel in case it did manage to do the actual completion. Reference to struct file isn't needed in aio_complete, but if aio_complete decided who won the race we'll have to put after it (or inside it if we want to make it common)
