static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
				 u32 total_sg_needed, unsigned char init_payload)
{
	u32 i = 0, j, page_offset = 0, sg_per_table;
	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
				sizeof(struct scatterlist));
	struct page *pg;
	struct scatterlist *sg;
	unsigned char *p;

	while (total_sg_needed) {
		sg_per_table = (total_sg_needed > max_sg_per_table) ?
			max_sg_per_table : total_sg_needed;

		sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
				GFP_KERNEL);
		if (!sg) {
			pr_err("Unable to allocate scatterlist array"
				" for struct rd_dev\n");
			return -ENOMEM;
		}

		sg_init_table(sg, sg_per_table);

		sg_table[i].sg_table = sg;
		sg_table[i].rd_sg_count = sg_per_table;
		sg_table[i].page_start_offset = page_offset;
		sg_table[i++].page_end_offset = (page_offset + sg_per_table)
						- 1;

		for (j = 0; j < sg_per_table; j++) {
			pg = alloc_pages(GFP_KERNEL, 0);
			if (!pg) {
				pr_err("Unable to allocate scatterlist"
					" pages for struct rd_dev_sg_table\n");
				return -ENOMEM;
			}
			sg_assign_page(&sg[j], pg);
			sg[j].length = PAGE_SIZE;

			p = kmap(pg);
			memset(p, init_payload, PAGE_SIZE);
			kunmap(pg);
		}

		page_offset += sg_per_table;
		total_sg_needed -= sg_per_table;
	}

	return 0;
}
static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
				 u32 total_sg_needed, unsigned char init_payload)
{
	u32 i = 0, j, page_offset = 0, sg_per_table;
	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
				sizeof(struct scatterlist));
	struct page *pg;
	struct scatterlist *sg;
	unsigned char *p;

	while (total_sg_needed) {
		sg_per_table = (total_sg_needed > max_sg_per_table) ?
			max_sg_per_table : total_sg_needed;

		sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
				GFP_KERNEL);
		if (!sg) {
			pr_err("Unable to allocate scatterlist array"
				" for struct rd_dev\n");
			return -ENOMEM;
		}

		sg_init_table(sg, sg_per_table);

		sg_table[i].sg_table = sg;
		sg_table[i].rd_sg_count = sg_per_table;
		sg_table[i].page_start_offset = page_offset;
		sg_table[i++].page_end_offset = (page_offset + sg_per_table)
						- 1;

		for (j = 0; j < sg_per_table; j++) {
			pg = alloc_pages(GFP_KERNEL, 0);
			if (!pg) {
				pr_err("Unable to allocate scatterlist"
					" pages for struct rd_dev_sg_table\n");
				return -ENOMEM;
			}
			sg_assign_page(&sg[j], pg);
			sg[j].length = PAGE_SIZE;

			p = kmap(pg);
			memset(p, init_payload, PAGE_SIZE);
			kunmap(pg);
		}

		page_offset += sg_per_table;
		total_sg_needed -= sg_per_table;
	}

	return 0;
}