RDMA/rdmavt: Adapt to handle non-uniform sizes on umem SGEs

rdmavt expects a uniform size on all umem SGEs which is currently at
PAGE_SIZE.

Adapt to a umem API change which could return non-uniform sized SGEs due
to combining contiguous PAGE_SIZE regions into an SGE. Use
for_each_sg_page variant to unfold the larger SGEs into a list of
PAGE_SIZE elements.

Additionally, purge umem->page_shift usage in the driver as its only
relevant for ODP MRs. Use system page size and shift instead.
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Shiraz, Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/rdmavt/mr.c

@@ -381,8 +381,8 @@ struct ib_mr *rvt_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 {
 	struct rvt_mr *mr;
 	struct ib_umem *umem;
-	struct scatterlist *sg;
-	int n, m, entry;
+	struct sg_page_iter sg_iter;
+	int n, m;
 	struct ib_mr *ret;
 
 	if (length == 0)
@@ -407,23 +407,21 @@ struct ib_mr *rvt_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	mr->mr.access_flags = mr_access_flags;
 	mr->umem = umem;
 
-	mr->mr.page_shift = umem->page_shift;
+	mr->mr.page_shift = PAGE_SHIFT;
 	m = 0;
 	n = 0;
-	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
+	for_each_sg_page (umem->sg_head.sgl, &sg_iter, umem->nmap, 0) {
 		void *vaddr;
 
-		vaddr = page_address(sg_page(sg));
+		vaddr = page_address(sg_page_iter_page(&sg_iter));
 		if (!vaddr) {
 			ret = ERR_PTR(-EINVAL);
 			goto bail_inval;
 		}
 		mr->mr.map[m]->segs[n].vaddr = vaddr;
-		mr->mr.map[m]->segs[n].length = BIT(umem->page_shift);
-		trace_rvt_mr_user_seg(&mr->mr, m, n, vaddr,
-				      BIT(umem->page_shift));
-		n++;
-		if (n == RVT_SEGSZ) {
+		mr->mr.map[m]->segs[n].length = PAGE_SIZE;
+		trace_rvt_mr_user_seg(&mr->mr, m, n, vaddr, PAGE_SIZE);
+		if (++n == RVT_SEGSZ) {
 			m++;
 			n = 0;
 		}