From 75cda62d9ca2cd3fab0412d438fcd1bfa0580b3d Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 9 Jan 2017 14:20:49 +0100 Subject: [PATCH] xfrm: state: simplify rcu_read_unlock handling in two spots Instead of: if (foo) { unlock(); return bar(); } unlock(); do: unlock(); if (foo) return bar(); This is ok because rcu protected structure is only dereferenced before the conditional. Signed-off-by: Florian Westphal Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_state.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index b5dad899fb0e..a62097e640b5 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -231,17 +231,18 @@ retry: return NULL; typemap = afinfo->type_map; - type = typemap[proto]; + type = READ_ONCE(typemap[proto]); if (unlikely(type && !try_module_get(type->owner))) type = NULL; + + rcu_read_unlock(); + if (!type && !modload_attempted) { - rcu_read_unlock(); request_module("xfrm-type-%d-%d", family, proto); modload_attempted = 1; goto retry; } - rcu_read_unlock(); return type; } @@ -327,17 +328,17 @@ retry: if (unlikely(afinfo == NULL)) return NULL; - mode = afinfo->mode_map[encap]; + mode = READ_ONCE(afinfo->mode_map[encap]); if (unlikely(mode && !try_module_get(mode->owner))) mode = NULL; + + rcu_read_unlock(); if (!mode && !modload_attempted) { - rcu_read_unlock(); request_module("xfrm-mode-%d-%d", family, encap); modload_attempted = 1; goto retry; } - rcu_read_unlock(); return mode; } -- 2.20.1