direct-io: eliminate the offset argument to ->direct_IO

Including blkdev_direct_IO and dax_do_io.  It has to be ki_pos to actually
work, so eliminate the superflous argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 981a1fc..79b298d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3334,12 +3334,12 @@
  * if the machine crashes during the write.
  *
  */
-static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-				  loff_t offset)
+static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	ssize_t ret;
+	loff_t offset = iocb->ki_pos;
 	size_t count = iov_iter_count(iter);
 	int overwrite = 0;
 	get_block_t *get_block_func = NULL;
@@ -3348,7 +3348,7 @@
 
 	/* Use the old path for reads and writes beyond i_size. */
 	if (iov_iter_rw(iter) != WRITE || final_size > inode->i_size)
-		return ext4_ind_direct_IO(iocb, iter, offset);
+		return ext4_ind_direct_IO(iocb, iter);
 
 	BUG_ON(iocb->private == NULL);
 
@@ -3400,11 +3400,11 @@
 	BUG_ON(ext4_encrypted_inode(inode) && S_ISREG(inode->i_mode));
 #endif
 	if (IS_DAX(inode))
-		ret = dax_do_io(iocb, inode, iter, offset, get_block_func,
+		ret = dax_do_io(iocb, inode, iter, get_block_func,
 				ext4_end_io_dio, dio_flags);
 	else
 		ret = __blockdev_direct_IO(iocb, inode,
-					   inode->i_sb->s_bdev, iter, offset,
+					   inode->i_sb->s_bdev, iter,
 					   get_block_func,
 					   ext4_end_io_dio, NULL, dio_flags);
 
@@ -3431,12 +3431,12 @@
 	return ret;
 }
 
-static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
-			      loff_t offset)
+static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct inode *inode = file->f_mapping->host;
 	size_t count = iov_iter_count(iter);
+	loff_t offset = iocb->ki_pos;
 	ssize_t ret;
 
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
@@ -3456,9 +3456,9 @@
 
 	trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
-		ret = ext4_ext_direct_IO(iocb, iter, offset);
+		ret = ext4_ext_direct_IO(iocb, iter);
 	else
-		ret = ext4_ind_direct_IO(iocb, iter, offset);
+		ret = ext4_ind_direct_IO(iocb, iter);
 	trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
 	return ret;
 }