RDMA/efa: Use API to get contiguous memory blocks aligned to device supported page size

Use the ib_umem_find_best_pgsz() and rdma_for_each_block() API when
registering an MR instead of coding it in the driver.

ib_umem_find_best_pgsz() is used to find the best suitable page size
which replaces the existing efa_cont_pages() implementation.
rdma_for_each_block() is used to iterate the umem in aligned contiguous
memory blocks.

Reviewed-by: Firas JahJah <firasj@amazon.com>
Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
Reviewed-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/efa/efa_verbs.c

@@ -1011,21 +1011,15 @@ static int umem_to_page_list(struct efa_dev *dev,
 			     u8 hp_shift)
 {
 	u32 pages_in_hp = BIT(hp_shift - PAGE_SHIFT);
-	struct sg_dma_page_iter sg_iter;
-	unsigned int page_idx = 0;
+	struct ib_block_iter biter;
 	unsigned int hp_idx = 0;
 
 	ibdev_dbg(&dev->ibdev, "hp_cnt[%u], pages_in_hp[%u]\n",
 		  hp_cnt, pages_in_hp);
 
-	for_each_sg_dma_page(umem->sg_head.sgl, &sg_iter, umem->nmap, 0) {
-		if (page_idx % pages_in_hp == 0) {
-			page_list[hp_idx] = sg_page_iter_dma_address(&sg_iter);
-			hp_idx++;
-		}
-
-		page_idx++;
-	}
+	rdma_for_each_block(umem->sg_head.sgl, &biter, umem->nmap,
+			    BIT(hp_shift))
+		page_list[hp_idx++] = rdma_block_iter_dma_address(&biter);
 
 	return 0;
 }
@@ -1356,56 +1350,6 @@ static int efa_create_pbl(struct efa_dev *dev,
 	return 0;
 }
 
-static void efa_cont_pages(struct ib_umem *umem, u64 addr,
-			   unsigned long max_page_shift,
-			   int *count, u8 *shift, u32 *ncont)
-{
-	struct scatterlist *sg;
-	u64 base = ~0, p = 0;
-	unsigned long tmp;
-	unsigned long m;
-	u64 len, pfn;
-	int i = 0;
-	int entry;
-
-	addr = addr >> PAGE_SHIFT;
-	tmp = (unsigned long)addr;
-	m = find_first_bit(&tmp, BITS_PER_LONG);
-	if (max_page_shift)
-		m = min_t(unsigned long, max_page_shift - PAGE_SHIFT, m);
-
-	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
-		len = DIV_ROUND_UP(sg_dma_len(sg), PAGE_SIZE);
-		pfn = sg_dma_address(sg) >> PAGE_SHIFT;
-		if (base + p != pfn) {
-			/*
-			 * If either the offset or the new
-			 * base are unaligned update m
-			 */
-			tmp = (unsigned long)(pfn | p);
-			if (!IS_ALIGNED(tmp, 1 << m))
-				m = find_first_bit(&tmp, BITS_PER_LONG);
-
-			base = pfn;
-			p = 0;
-		}
-
-		p += len;
-		i += len;
-	}
-
-	if (i) {
-		m = min_t(unsigned long, ilog2(roundup_pow_of_two(i)), m);
-		*ncont = DIV_ROUND_UP(i, (1 << m));
-	} else {
-		m = 0;
-		*ncont = 0;
-	}
-
-	*shift = PAGE_SHIFT + m;
-	*count = i;
-}
-
 struct ib_mr *efa_reg_mr(struct ib_pd *ibpd, u64 start, u64 length,
 			 u64 virt_addr, int access_flags,
 			 struct ib_udata *udata)
@@ -1413,11 +1357,10 @@ struct ib_mr *efa_reg_mr(struct ib_pd *ibpd, u64 start, u64 length,
 	struct efa_dev *dev = to_edev(ibpd->device);
 	struct efa_com_reg_mr_params params = {};
 	struct efa_com_reg_mr_result result = {};
-	unsigned long max_page_shift;
 	struct pbl_context pbl;
+	unsigned int pg_sz;
 	struct efa_mr *mr;
 	int inline_size;
-	int npages;
 	int err;
 
 	if (udata->inlen &&
@@ -1454,13 +1397,24 @@ struct ib_mr *efa_reg_mr(struct ib_pd *ibpd, u64 start, u64 length,
 	params.iova = virt_addr;
 	params.mr_length_in_bytes = length;
 	params.permissions = access_flags & 0x1;
-	max_page_shift = fls64(dev->dev_attr.page_size_cap);
 
-	efa_cont_pages(mr->umem, start, max_page_shift, &npages,
-		       &params.page_shift, &params.page_num);
+	pg_sz = ib_umem_find_best_pgsz(mr->umem,
+				       dev->dev_attr.page_size_cap,
+				       virt_addr);
+	if (!pg_sz) {
+		err = -EOPNOTSUPP;
+		ibdev_dbg(&dev->ibdev, "Failed to find a suitable page size in page_size_cap %#llx\n",
+			  dev->dev_attr.page_size_cap);
+		goto err_unmap;
+	}
+
+	params.page_shift = __ffs(pg_sz);
+	params.page_num = DIV_ROUND_UP(length + (start & (pg_sz - 1)),
+				       pg_sz);
+
 	ibdev_dbg(&dev->ibdev,
-		  "start %#llx length %#llx npages %d params.page_shift %u params.page_num %u\n",
-		  start, length, npages, params.page_shift, params.page_num);
+		  "start %#llx length %#llx params.page_shift %u params.page_num %u\n",
+		  start, length, params.page_shift, params.page_num);
 
 	inline_size = ARRAY_SIZE(params.pbl.inline_pbl_array);
 	if (params.page_num <= inline_size) {