aio: Kill ki_dtor

sock_aio_dtor() is dead code - and stuff that does need to do cleanup
can simply do it before calling aio_complete().

Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Zach Brown <zab@redhat.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>

include/linux/aio.h

@@ -33,7 +33,6 @@ struct kiocb {
 	struct file		*ki_filp;
 	struct kioctx		*ki_ctx;	/* NULL for sync ops */
 	kiocb_cancel_fn		*ki_cancel;
-	void			(*ki_dtor)(struct kiocb *);
 	void			*private;
 
 	union {