Don't reference the kiocb structure from the common aio code, and move
any use of it into helper specific to the read/write path.  This is in
preparation for aio_poll support that wants to use the space for different
fields.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Moyer <redacted>
Reviewed-by: Darrick J. Wong <redacted>
---
 fs/aio.c | 171 ++++++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 97 insertions(+), 74 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 41fc8ce6bc7f..6295fc00f104 100644
--- a/fs/aio.c
+++ b/fs/aio.c

@@ -170,7 +170,9 @@ struct kioctx {
 #define KIOCB_CANCELLED		((void *) (~0ULL))
 
 struct aio_kiocb {
-	struct kiocb		common;
+	union {
+		struct kiocb		rw;
+	};
 
 	struct kioctx		*ki_ctx;
 	kiocb_cancel_fn		*ki_cancel;

@@ -549,7 +551,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
 
 void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
 {
-	struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, common);
+	struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw);
 	struct kioctx *ctx = req->ki_ctx;
 	unsigned long flags;
 

@@ -582,7 +584,7 @@ static int kiocb_cancel(struct aio_kiocb *kiocb)
 		cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED);
 	} while (cancel != old);
 
-	return cancel(&kiocb->common);
+	return cancel(&kiocb->rw);
 }
 
 static void free_ioctx(struct work_struct *work)

@@ -1040,15 +1042,6 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
 	return NULL;
 }
 
-static void kiocb_free(struct aio_kiocb *req)
-{
-	if (req->common.ki_filp)
-		fput(req->common.ki_filp);
-	if (req->ki_eventfd != NULL)
-		eventfd_ctx_put(req->ki_eventfd);
-	kmem_cache_free(kiocb_cachep, req);
-}
-
 static struct kioctx *lookup_ioctx(unsigned long ctx_id)
 {
 	struct aio_ring __user *ring  = (void __user *)ctx_id;

@@ -1079,29 +1072,14 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id)
 /* aio_complete
  *	Called when the io request on the given iocb is complete.
  */
-static void aio_complete(struct kiocb *kiocb, long res, long res2)
+static void aio_complete(struct aio_kiocb *iocb, long res, long res2)
 {
-	struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, common);
 	struct kioctx	*ctx = iocb->ki_ctx;
 	struct aio_ring	*ring;
 	struct io_event	*ev_page, *event;
 	unsigned tail, pos, head;
 	unsigned long	flags;
 
-	BUG_ON(is_sync_kiocb(kiocb));