IB: Replace ib_umem page_size by page_shift

Size of pages are held by struct ib_umem in page_size field.

It is better to store it as an exponent, because page size by nature
is always power-of-two and used as a factor, divisor or ilog2's argument.

The conversion of page_size to be page_shift allows to have portable
code and avoid following error while compiling on ARM:

  ERROR: "__aeabi_uldivmod" [drivers/infiniband/core/ib_core.ko] undefined!

CC: Selvin Xavier <selvin.xavier@broadcom.com>
CC: Steve Wise <swise@chelsio.com>
CC: Lijun Ou <oulijun@huawei.com>
CC: Shiraz Saleem <shiraz.saleem@intel.com>
CC: Adit Ranadive <aditr@vmware.com>
CC: Dennis Dalessandro <dennis.dalessandro@intel.com>
CC: Ram Amrani <Ram.Amrani@Cavium.com>
Signed-off-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Acked-by: Ram Amrani <Ram.Amrani@cavium.com>
Acked-by: Shiraz Saleem <shiraz.saleem@intel.com>
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Acked-by: Adit Ranadive <aditr@vmware.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/sw/rdmavt/mr.c b/drivers/infiniband/sw/rdmavt/mr.c
index 7c86955..aa5f9ea3 100644
--- a/drivers/infiniband/sw/rdmavt/mr.c
+++ b/drivers/infiniband/sw/rdmavt/mr.c
@@ -408,8 +408,7 @@
 	mr->mr.access_flags = mr_access_flags;
 	mr->umem = umem;
 
-	if (is_power_of_2(umem->page_size))
-		mr->mr.page_shift = ilog2(umem->page_size);
+	mr->mr.page_shift = umem->page_shift;
 	m = 0;
 	n = 0;
 	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
@@ -421,8 +420,9 @@
 			goto bail_inval;
 		}
 		mr->mr.map[m]->segs[n].vaddr = vaddr;
-		mr->mr.map[m]->segs[n].length = umem->page_size;
-		trace_rvt_mr_user_seg(&mr->mr, m, n, vaddr, umem->page_size);
+		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) {
 			m++;