IB/core: Replace ib_umem's offset field with a full address

In order to allow umems that do not pin memory, we need the umem to
keep track of its region's address.

This makes the offset field redundant, and so this patch removes it.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c
index fef067c..c0d0296 100644
--- a/drivers/infiniband/hw/nes/nes_verbs.c
+++ b/drivers/infiniband/hw/nes/nes_verbs.c
@@ -2341,9 +2341,9 @@
 	nes_debug(NES_DBG_MR, "User base = 0x%lX, Virt base = 0x%lX, length = %u,"
 			" offset = %u, page size = %u.\n",
 			(unsigned long int)start, (unsigned long int)virt, (u32)length,
-			region->offset, region->page_size);
+			ib_umem_offset(region), region->page_size);
 
-	skip_pages = ((u32)region->offset) >> 12;
+	skip_pages = ((u32)ib_umem_offset(region)) >> 12;
 
 	if (ib_copy_from_udata(&req, udata, sizeof(req))) {
 		ib_umem_release(region);
@@ -2408,7 +2408,7 @@
 				region_length -= skip_pages << 12;
 				for (page_index = skip_pages; page_index < chunk_pages; page_index++) {
 					skip_pages = 0;
-					if ((page_count != 0) && (page_count<<12)-(region->offset&(4096-1)) >= region->length)
+					if ((page_count != 0) && (page_count << 12) - (ib_umem_offset(region) & (4096 - 1)) >= region->length)
 						goto enough_pages;
 					if ((page_count&0x01FF) == 0) {
 						if (page_count >= 1024 * 512) {