s390/pci: use virtual memory for iommu bitmap

The bitmap used to mark dma mappings can be quite large on systems
with huge amounts of memory. Use virtual memory for this bitmap.
Suggested-by: Alexander Schmidt <alexschm@de.ibm.com>
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

@@ -10,6 +10,7 @@
 #include <linux/export.h>
 #include <linux/iommu-helper.h>
 #include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
 #include <linux/pci.h>
 #include <asm/pci_dma.h>
 
@@ -407,7 +408,6 @@ static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 
 int zpci_dma_init_device(struct zpci_dev *zdev)
 {
-	unsigned int bitmap_order;
 	int rc;
 
 	spin_lock_init(&zdev->iommu_bitmap_lock);
@@ -421,12 +421,7 @@ int zpci_dma_init_device(struct zpci_dev *zdev)
 
 	zdev->iommu_size = (unsigned long) high_memory - PAGE_OFFSET;
 	zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
-	bitmap_order = get_order(zdev->iommu_pages / 8);
-	pr_info("iommu_size: 0x%lx  iommu_pages: 0x%lx  bitmap_order: %i\n",
-		 zdev->iommu_size, zdev->iommu_pages, bitmap_order);
-
-	zdev->iommu_bitmap = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
-						       bitmap_order);
+	zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
 	if (!zdev->iommu_bitmap) {
 		rc = -ENOMEM;
 		goto out_reg;
@@ -451,8 +446,7 @@ void zpci_dma_exit_device(struct zpci_dev *zdev)
 {
 	zpci_unregister_ioat(zdev, 0);
 	dma_cleanup_tables(zdev);
-	free_pages((unsigned long) zdev->iommu_bitmap,
-		   get_order(zdev->iommu_pages / 8));
+	vfree(zdev->iommu_bitmap);
 	zdev->iommu_bitmap = NULL;
 	zdev->next_bit = 0;
 }