From a93639090a2743c8e205c1ac25439702702b4ce4 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 14 Dec 2017 15:43:43 +1100 Subject: [PATCH] staging: lustre: lnet: Fix recent breakage from list_for_each conversion Commit 8e55b6fd0660 ("staging: lustre: lnet: replace list_for_each with list_for_each_entry") was intended to be an idempotent change, but actually broke the behavior of ksocknal_add_peer() causing mounts to fail. The fact that it caused an existing "route2 = NULL;" to become redundant could have been a clue. The fact that the loop body set the new loop variable to NULL might also have been a clue The original code relied on "route2" being NULL if nothing was found. The new code would always set route2 to a non-NULL value if the list was empty, and would likely crash if the list was not empty. Restore correct functionality by using code-flow rather the value of "route2" to determine whether to use on old route, or to add a new one. Fixes: 8e55b6fd0660 ("staging: lustre: lnet: replace list_for_each with list_for_each_entry") Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- .../lustre/lnet/klnds/socklnd/socklnd.c | 23 ++++++++----------- 1 file changed, 10 insertions(+), 13 deletions(-) diff --git a/drivers/staging/lustre/lnet/klnds/socklnd/socklnd.c b/drivers/staging/lustre/lnet/klnds/socklnd/socklnd.c index 986c2a40d978..8267119ccc8e 100644 --- a/drivers/staging/lustre/lnet/klnds/socklnd/socklnd.c +++ b/drivers/staging/lustre/lnet/klnds/socklnd/socklnd.c @@ -487,21 +487,18 @@ ksocknal_add_peer(struct lnet_ni *ni, struct lnet_process_id id, __u32 ipaddr, ksocknal_nid2peerlist(id.nid)); } - route2 = NULL; list_for_each_entry(route2, &peer->ksnp_routes, ksnr_list) { - if (route2->ksnr_ipaddr == ipaddr) - break; - - route2 = NULL; + if (route2->ksnr_ipaddr == ipaddr) { + /* Route already exists, use the old one */ + ksocknal_route_decref(route); + route2->ksnr_share_count++; + goto out; + } } - if (!route2) { - ksocknal_add_route_locked(peer, route); - route->ksnr_share_count++; - } else { - ksocknal_route_decref(route); - route2->ksnr_share_count++; - } - + /* Route doesn't already exist, add the new one */ + ksocknal_add_route_locked(peer, route); + route->ksnr_share_count++; +out: write_unlock_bh(&ksocknal_data.ksnd_global_lock); return 0;