fs/aio.c           | 83 ++++++++++++++++++++++--------------------------------
 include/linux/fs.h |  8 +++++-
 2 files changed, 41 insertions(+), 50 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index aaaaf4d12c73..9eccd2ea6ca9 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -167,14 +167,18 @@ struct kioctx {
 	unsigned		id;
 };
 
+/*
+ * First field must be 'ki_filp' in all the
+ * iocb unions!
+ */
 struct fsync_iocb {
+	struct file		*ki_filp;
 	struct work_struct	work;
-	struct file		*file;
 	bool			datasync;
 };
 
 struct poll_iocb {
-	struct file		*file;
+	struct file		*ki_filp;
 	struct wait_queue_head	*head;
 	__poll_t		events;
 	bool			woken;
@@ -183,8 +187,15 @@ struct poll_iocb {
 	struct work_struct	work;
 };
 
+/*
+ * NOTE! Each of the iocb union members has "ki_filp" as
+ * the first entry in their struct definition. So you can
+ * access the file pointer either directly through this
+ * anonymous union, or through any of the sub-structs.
+ */
 struct aio_kiocb {
 	union {
+		struct file		*ki_filp;
 		struct kiocb		rw;
 		struct fsync_iocb	fsync;
 		struct poll_iocb	poll;
@@ -1060,6 +1071,7 @@ static inline void iocb_put(struct aio_kiocb *iocb)
 {
 	if (refcount_read(&iocb->ki_refcnt) == 0 ||
 	    refcount_dec_and_test(&iocb->ki_refcnt)) {
+		fput(iocb->ki_filp);
 		percpu_ref_put(&iocb->ki_ctx->reqs);
 		kmem_cache_free(kiocb_cachep, iocb);
 	}
@@ -1413,7 +1425,7 @@ static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
 		aio_remove_iocb(iocb);
 
 	if (kiocb->ki_flags & IOCB_WRITE) {
-		struct inode *inode = file_inode(kiocb->ki_filp);
+		struct inode *inode = file_inode(iocb->ki_filp);
 
 		/*
 		 * Tell lockdep we inherited freeze protection from submission
@@ -1421,10 +1433,9 @@ static void aio_complete_rw(struct kiocb *kiocb, long res, long res2)
 		 */
 		if (S_ISREG(inode->i_mode))
 			__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
-		file_end_write(kiocb->ki_filp);
+		file_end_write(iocb->ki_filp);
 	}
 
-	fput(kiocb->ki_filp);
 	aio_complete(iocb, res, res2);
 }
 
@@ -1432,9 +1443,6 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
 {
 	int ret;
 
-	req->ki_filp = fget(iocb->aio_fildes);
-	if (unlikely(!req->ki_filp))
-		return -EBADF;
 	req->ki_complete = aio_complete_rw;
 	req->private = NULL;
 	req->ki_pos = iocb->aio_offset;
@@ -1451,7 +1459,7 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
 		ret = ioprio_check_cap(iocb->aio_reqprio);
 		if (ret) {
 			pr_debug("aio ioprio check cap error: %d\n", ret);
-			goto out_fput;
+			return ret;
 		}
 
 		req->ki_ioprio = iocb->aio_reqprio;
@@ -1460,14 +1468,10 @@ static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb)
 
 	ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags);
 	if (unlikely(ret))
-		goto out_fput;
+		return ret;
 
 	req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */
 	return 0;
-
-out_fput:
-	fput(req->ki_filp);
-	return ret;
 }
 
 static int aio_setup_rw(int rw, const struct iocb *iocb, struct iovec **iovec,
@@ -1521,24 +1525,19 @@ static ssize_t aio_read(struct kiocb *req, const struct iocb *iocb,
 	if (ret)
 		return ret;
 	file = req->ki_filp;
-
-	ret = -EBADF;
 	if (unlikely(!(file->f_mode & FMODE_READ)))
-		goto out_fput;
+		return -EBADF;
 	ret = -EINVAL;
 	if (unlikely(!file->f_op->read_iter))
-		goto out_fput;
+		return -EINVAL;
 
 	ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter);
 	if (ret)
-		goto out_fput;
+		return ret;
 	ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
 	if (!ret)
 		aio_rw_done(req, call_read_iter(file, req, &iter));
 	kfree(iovec);
-out_fput:
-	if (unlikely(ret))
-		fput(file);
 	return ret;
 }
 
@@ -1555,16 +1554,14 @@ static ssize_t aio_write(struct kiocb *req, const struct iocb *iocb,
 		return ret;
 	file = req->ki_filp;
 
-	ret = -EBADF;
 	if (unlikely(!(file->f_mode & FMODE_WRITE)))
-		goto out_fput;
-	ret = -EINVAL;
+		return -EBADF;
 	if (unlikely(!file->f_op->write_iter))
-		goto out_fput;
+		return -EINVAL;
 
 	ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter);
 	if (ret)
-		goto out_fput;
+		return ret;
 	ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
 	if (!ret) {
 		/*
@@ -1582,9 +1579,6 @@ static ssize_t aio_write(struct kiocb *req, const struct iocb *iocb,
 		aio_rw_done(req, call_write_iter(file, req, &iter));
 	}
 	kfree(iovec);
-out_fput:
-	if (unlikely(ret))
-		fput(file);
 	return ret;
 }
 
@@ -1593,8 +1587,7 @@ static void aio_fsync_work(struct work_struct *work)
 	struct fsync_iocb *req = container_of(work, struct fsync_iocb, work);
 	int ret;
 
-	ret = vfs_fsync(req->file, req->datasync);
-	fput(req->file);
+	ret = vfs_fsync(req->ki_filp, req->datasync);
 	aio_complete(container_of(req, struct aio_kiocb, fsync), ret, 0);
 }
 
@@ -1605,13 +1598,8 @@ static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
 			iocb->aio_rw_flags))
 		return -EINVAL;
 
-	req->file = fget(iocb->aio_fildes);
-	if (unlikely(!req->file))
-		return -EBADF;
-	if (unlikely(!req->file->f_op->fsync)) {
-		fput(req->file);
+	if (unlikely(!req->ki_filp->f_op->fsync))
 		return -EINVAL;
-	}
 
 	req->datasync = datasync;
 	INIT_WORK(&req->work, aio_fsync_work);
@@ -1621,10 +1609,7 @@ static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
 
 static inline void aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask)
 {
-	struct file *file = iocb->poll.file;
-
 	aio_complete(iocb, mangle_poll(mask), 0);
-	fput(file);
 }
 
 static void aio_poll_complete_work(struct work_struct *work)
@@ -1636,7 +1621,7 @@ static void aio_poll_complete_work(struct work_struct *work)
 	__poll_t mask = 0;
 
 	if (!READ_ONCE(req->cancelled))
-		mask = vfs_poll(req->file, &pt) & req->events;
+		mask = vfs_poll(iocb->ki_filp, &pt) & req->events;
 
 	/*
 	 * Note that ->ki_cancel callers also delete iocb from active_reqs after
@@ -1743,9 +1728,6 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
 
 	INIT_WORK(&req->work, aio_poll_complete_work);
 	req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
-	req->file = fget(iocb->aio_fildes);
-	if (unlikely(!req->file))
-		return -EBADF;
 
 	req->head = NULL;
 	req->woken = false;
@@ -1763,7 +1745,7 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
 	/* one for removal from waitqueue, one for this function */
 	refcount_set(&aiocb->ki_refcnt, 2);
 
-	mask = vfs_poll(req->file, &apt.pt) & req->events;
+	mask = vfs_poll(aiocb->ki_filp, &apt.pt) & req->events;
 	if (unlikely(!req->head)) {
 		/* we did not manage to set up a waitqueue, done */
 		goto out;
@@ -1788,10 +1770,8 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
 	spin_unlock_irq(&ctx->ctx_lock);
 
 out:
-	if (unlikely(apt.error)) {
-		fput(req->file);
+	if (unlikely(apt.error))
 		return apt.error;
-	}
 
 	if (mask)
 		aio_poll_complete(aiocb, mask);
@@ -1829,6 +1809,11 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
 	if (unlikely(!req))
 		goto out_put_reqs_available;
 
+	req->ki_filp = fget(iocb->aio_fildes);
+	ret = -EBADF;
+	if (unlikely(!req->ki_filp))
+		goto out_put_req;
+
 	if (iocb->aio_flags & IOCB_FLAG_RESFD) {
 		/*
 		 * If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 29d8e2cfed0e..fd423fec8d83 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -304,13 +304,19 @@ enum rw_hint {
 
 struct kiocb {
 	struct file		*ki_filp;
+
+	/* The 'ki_filp' pointer is shared in a union for aio */
+	randomized_struct_fields_start
+
 	loff_t			ki_pos;
 	void (*ki_complete)(struct kiocb *iocb, long ret, long ret2);
 	void			*private;
 	int			ki_flags;
 	u16			ki_hint;
 	u16			ki_ioprio; /* See linux/ioprio.h */
-} __randomize_layout;
+
+	randomized_struct_fields_end
+};
 
 static inline bool is_sync_kiocb(struct kiocb *kiocb)
 {