crush: eliminate CRUSH_MAX_SET result size limitation

This is only present to size the temporary scratch arrays that we put on
the stack.  Let the caller allocate them as they wish and remove the
limitation.

Reflects ceph.git commit 1cfe140bf2dab99517589a82a916f4c75b9492d1.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 6477a68..8b1a6b4 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -1110,6 +1110,16 @@
 }
 EXPORT_SYMBOL(ceph_calc_ceph_pg);
 
+static int crush_do_rule_ary(const struct crush_map *map, int ruleno, int x,
+			     int *result, int result_max,
+			     const __u32 *weight, int weight_max)
+{
+	int scratch[result_max * 3];
+
+	return crush_do_rule(map, ruleno, x, result, result_max,
+			     weight, weight_max, scratch);
+}
+
 /*
  * Calculate raw osd vector for the given pgid.  Return pointer to osd
  * array, or NULL on failure.
@@ -1163,9 +1173,9 @@
 				      pool->pgp_num_mask) +
 			(unsigned)pgid.pool;
 	}
-	r = crush_do_rule(osdmap->crush, ruleno, pps, osds,
-			  min_t(int, pool->size, *num),
-			  osdmap->osd_weight, osdmap->max_osd);
+	r = crush_do_rule_ary(osdmap->crush, ruleno, pps,
+			      osds, min_t(int, pool->size, *num),
+			      osdmap->osd_weight, osdmap->max_osd);
 	if (r < 0) {
 		pr_err("error %d from crush rule: pool %lld ruleset %d type %d"
 		       " size %d\n", r, pgid.pool, pool->crush_ruleset,