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>
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 2125310..7e5573a 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/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 @@
 
 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 @@
 
 	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 @@
 {
 	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;
 }