s390/pci/dma: fix accounting of allocated_pages

allocated_pages sometimes are increased even if s390_dma_alloc fails
also this value is never decreased even if s390_dma_free is called.
This patch fixes these bugs.
Also remove the atomic64_t casts (the members are already of this type).
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/pci/pci_dma.c

@@ -285,7 +285,7 @@ static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
 		flags |= ZPCI_TABLE_PROTECTED;
 
 	if (!dma_update_trans(zdev, pa, dma_addr, size, flags)) {
-		atomic64_add(nr_pages, (atomic64_t *) &zdev->fmb->mapped_pages);
+		atomic64_add(nr_pages, &zdev->fmb->mapped_pages);
 		return dma_addr + (offset & ~PAGE_MASK);
 	}
 
@@ -313,7 +313,7 @@ static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
 		zpci_err_hex(&dma_addr, sizeof(dma_addr));
 	}
 
-	atomic64_add(npages, (atomic64_t *) &zdev->fmb->unmapped_pages);
+	atomic64_add(npages, &zdev->fmb->unmapped_pages);
 	iommu_page_index = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
 	dma_free_iommu(zdev, iommu_page_index, npages);
 }
@@ -332,7 +332,6 @@ static void *s390_dma_alloc(struct device *dev, size_t size,
 	if (!page)
 		return NULL;
 
-	atomic64_add(size / PAGE_SIZE, (atomic64_t *) &zdev->fmb->allocated_pages);
 	pa = page_to_phys(page);
 	memset((void *) pa, 0, size);
 
@@ -343,6 +342,7 @@ static void *s390_dma_alloc(struct device *dev, size_t size,
 		return NULL;
 	}
 
+	atomic64_add(size / PAGE_SIZE, &zdev->fmb->allocated_pages);
 	if (dma_handle)
 		*dma_handle = map;
 	return (void *) pa;
@@ -352,8 +352,11 @@ static void s390_dma_free(struct device *dev, size_t size,
 			  void *pa, dma_addr_t dma_handle,
 			  struct dma_attrs *attrs)
 {
-	s390_dma_unmap_pages(dev, dma_handle, PAGE_ALIGN(size),
-			     DMA_BIDIRECTIONAL, NULL);
+	struct zpci_dev *zdev = get_zdev(to_pci_dev(dev));
+
+	size = PAGE_ALIGN(size);
+	atomic64_sub(size / PAGE_SIZE, &zdev->fmb->allocated_pages);
+	s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, NULL);
 	free_pages((unsigned long) pa, get_order(size));
 }