[openib-general] Re: [PATCH updated] mthca: fix page shift calculation

[Roland Dreier]

    Michael> Fix page shift calculation: for all pages except possibly
    Michael> the last one, the byte beyond the buffer end must be page
    Michael> aligned.

Good catch.  But it seems to me that we don't have to worry about the
first page either, because of the trick

	buffer_list[0].size += buffer_list[0].addr & ((1ULL << shift) - 1);
	buffer_list[0].addr &= ~0ull << shift;

later on.  Does the patch below make sense?

 - R.

--- infiniband/hw/mthca/mthca_provider.c	(revision 4754)
+++ infiniband/hw/mthca/mthca_provider.c	(working copy)
@@ -778,17 +778,17 @@ static struct ib_mr *mthca_reg_phys_mr(s
 	mask = 0;
 	total_size = 0;
 	for (i = 0; i < num_phys_buf; ++i) {
-		if (i != 0 && buffer_list[i].addr & ~PAGE_MASK)
-			return ERR_PTR(-EINVAL);
-		if (i != 0 && i != num_phys_buf - 1 &&
-		    (buffer_list[i].size & ~PAGE_MASK))
-			return ERR_PTR(-EINVAL);
+		if (i != 0)
+			mask |= buffer_list[i].addr;
+		if (i != 0 && i != num_phys_buf - 1)
+			mask |= buffer_list[i].size;
 
 		total_size += buffer_list[i].size;
-		if (i > 0)
-			mask |= buffer_list[i].addr;
 	}
 
+	if (mask & ~PAGE_MASK)
+		return ERR_PTR(-EINVAL);
+
 	/* Find largest page shift we can use to cover buffers */
 	for (shift = PAGE_SHIFT; shift < 31; ++shift)
 		if (num_phys_buf > 1) {