int afu_dma_map_region()

in dfl-afu-dma-region.c [301:370]

• 51 lines of code
• 10 McCabe index (conditional complexity)

int afu_dma_map_region(struct dfl_feature_platform_data *pdata,
		       u64 user_addr, u64 length, u64 *iova)
{
	struct dfl_afu_dma_region *region;
	int ret;

	/*
	 * Check Inputs, only accept page-aligned user memory region with
	 * valid length.
	 */
	if (!PAGE_ALIGNED(user_addr) || !PAGE_ALIGNED(length) || !length)
		return -EINVAL;

	/* Check overflow */
	if (user_addr + length < user_addr)
		return -EINVAL;

	region = kzalloc(sizeof(*region), GFP_KERNEL);
	if (!region)
		return -ENOMEM;

	region->user_addr = user_addr;
	region->length = length;

	/* Pin the user memory region */
	ret = afu_dma_pin_pages(pdata, region);
	if (ret) {
		dev_err(&pdata->dev->dev, "failed to pin memory region\n");
		goto free_region;
	}

	/* Only accept continuous pages, return error else */
	if (!afu_dma_check_continuous_pages(region)) {
		dev_err(&pdata->dev->dev, "pages are not continuous\n");
		ret = -EINVAL;
		goto unpin_pages;
	}

	/* As pages are continuous then start to do DMA mapping */
	region->iova = dma_map_page(dfl_fpga_pdata_to_parent(pdata),
				    region->pages[0], 0,
				    region->length,
				    DMA_BIDIRECTIONAL);
	if (dma_mapping_error(dfl_fpga_pdata_to_parent(pdata), region->iova)) {
		dev_err(&pdata->dev->dev, "failed to map for dma\n");
		ret = -EFAULT;
		goto unpin_pages;
	}

	*iova = region->iova;

	mutex_lock(&pdata->lock);
	ret = afu_dma_region_add(pdata, region);
	mutex_unlock(&pdata->lock);
	if (ret) {
		dev_err(&pdata->dev->dev, "failed to add dma region\n");
		goto unmap_dma;
	}

	return 0;

unmap_dma:
	dma_unmap_page(dfl_fpga_pdata_to_parent(pdata),
		       region->iova, region->length, DMA_BIDIRECTIONAL);
unpin_pages:
	afu_dma_unpin_pages(pdata, region);
free_region:
	kfree(region);
	return ret;
}