powerpc/powernv/ioda: Remove obsolete iommu_table_ops::exchange callbacks

As now we have xchg_no_kill/tce_kill, these are not used anymore so
remove them.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190829085252.72370-6-aik@ozlabs.ru

arch/powerpc/kernel/iommu.c

@@ -981,30 +981,6 @@ int iommu_tce_check_gpa(unsigned long page_shift, unsigned long gpa)
 }
 EXPORT_SYMBOL_GPL(iommu_tce_check_gpa);
 
-long iommu_tce_xchg(struct mm_struct *mm, struct iommu_table *tbl,
-		unsigned long entry, unsigned long *hpa,
-		enum dma_data_direction *direction)
-{
-	long ret;
-	unsigned long size = 0;
-
-	ret = tbl->it_ops->exchange(tbl, entry, hpa, direction);
-
-	if (!ret && ((*direction == DMA_FROM_DEVICE) ||
-			(*direction == DMA_BIDIRECTIONAL)) &&
-			!mm_iommu_is_devmem(mm, *hpa, tbl->it_page_shift,
-					&size))
-		SetPageDirty(pfn_to_page(*hpa >> PAGE_SHIFT));
-
-	/* if (unlikely(ret))
-		pr_err("iommu_tce: %s failed on hwaddr=%lx ioba=%lx kva=%lx ret=%d\n",
-			__func__, hwaddr, entry << tbl->it_page_shift,
-				hwaddr, ret); */
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(iommu_tce_xchg);
-
 extern long iommu_tce_xchg_no_kill(struct mm_struct *mm,
 		struct iommu_table *tbl,
 		unsigned long entry, unsigned long *hpa,
@@ -1044,7 +1020,7 @@ int iommu_take_ownership(struct iommu_table *tbl)
 	 * requires exchange() callback defined so if it is not
 	 * implemented, we disallow taking ownership over the table.
 	 */
-	if (!tbl->it_ops->exchange)
+	if (!tbl->it_ops->xchg_no_kill)
 		return -EINVAL;
 
 	spin_lock_irqsave(&tbl->large_pool.lock, flags);