static void alpha_pci_unmap_page()

in kernel/pci_iommu.c [349:406]

• 41 lines of code
• 9 McCabe index (conditional complexity)

static void alpha_pci_unmap_page(struct device *dev, dma_addr_t dma_addr,
				 size_t size, enum dma_data_direction dir,
				 unsigned long attrs)
{
	unsigned long flags;
	struct pci_dev *pdev = alpha_gendev_to_pci(dev);
	struct pci_controller *hose = pdev ? pdev->sysdata : pci_isa_hose;
	struct pci_iommu_arena *arena;
	long dma_ofs, npages;

	BUG_ON(dir == PCI_DMA_NONE);

	if (dma_addr >= __direct_map_base
	    && dma_addr < __direct_map_base + __direct_map_size) {
		/* Nothing to do.  */

		DBGA2("pci_unmap_single: direct [%llx,%zx] from %ps\n",
		      dma_addr, size, __builtin_return_address(0));

		return;
	}

	if (dma_addr > 0xffffffff) {
		DBGA2("pci64_unmap_single: DAC [%llx,%zx] from %ps\n",
		      dma_addr, size, __builtin_return_address(0));
		return;
	}

	arena = hose->sg_pci;
	if (!arena || dma_addr < arena->dma_base)
		arena = hose->sg_isa;

	dma_ofs = (dma_addr - arena->dma_base) >> PAGE_SHIFT;
	if (dma_ofs * PAGE_SIZE >= arena->size) {
		printk(KERN_ERR "Bogus pci_unmap_single: dma_addr %llx "
		       " base %llx size %x\n",
		       dma_addr, arena->dma_base, arena->size);
		return;
		BUG();
	}

	npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);

	spin_lock_irqsave(&arena->lock, flags);

	iommu_arena_free(arena, dma_ofs, npages);

        /* If we're freeing ptes above the `next_entry' pointer (they
           may have snuck back into the TLB since the last wrap flush),
           we need to flush the TLB before reallocating the latter.  */
	if (dma_ofs >= arena->next_entry)
		alpha_mv.mv_pci_tbi(hose, dma_addr, dma_addr + size - 1);

	spin_unlock_irqrestore(&arena->lock, flags);

	DBGA2("pci_unmap_single: sg [%llx,%zx] np %ld from %ps\n",
	      dma_addr, size, npages, __builtin_return_address(0));
}