swiotlb: pass a gfp_mask argument to swiotlb_init_late

Let the caller chose a zone to allocate from.  This will be used
later on by the xen-swiotlb initialization on arm.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

Author: Christoph Hellwig

arch/x86/pci/sta2x11-fixup.c

@@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev)
 		int size = STA2X11_SWIOTLB_SIZE;
 		/* First instance: register your own swiotlb area */
 		dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size);
-		if (swiotlb_init_late(size))
+		if (swiotlb_init_late(size, GFP_DMA))
 			dev_emerg(&pdev->dev, "init swiotlb failed\n");
 	}
 	list_add(&instance->list, &sta2x11_instance_list);

include/linux/swiotlb.h

@@ -37,7 +37,7 @@ struct scatterlist;
 int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, unsigned int flags);
 unsigned long swiotlb_size_or_default(void);
 extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
-int swiotlb_init_late(size_t size);
+int swiotlb_init_late(size_t size, gfp_t gfp_mask);
 extern void __init swiotlb_update_mem_attributes(void);
 
 phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys,

kernel/dma/swiotlb.c

@@ -292,7 +292,7 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags)
  * initialize the swiotlb later using the slab allocator if needed.
  * This should be just like above, but with some error catching.
  */
-int swiotlb_init_late(size_t size)
+int swiotlb_init_late(size_t size, gfp_t gfp_mask)
 {
 	unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
 	unsigned long bytes;
@@ -303,15 +303,12 @@ int swiotlb_init_late(size_t size)
 	if (swiotlb_force_disable)
 		return 0;
 
-	/*
-	 * Get IO TLB memory from the low pages
-	 */
 	order = get_order(nslabs << IO_TLB_SHIFT);
 	nslabs = SLABS_PER_PAGE << order;
 	bytes = nslabs << IO_TLB_SHIFT;
 
 	while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
-		vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
+		vstart = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN,
 						  order);
 		if (vstart)
 			break;