qeth: avoid duplicate deletion of multicast addresses

if qeth_set_multicast_list() is performed on 2 CPUs in parallel,
card->ip_list may end corrupted.
Solution: In function __qeth_delete_all_mc()
          remove card->ip_list entry before invoking
          qeth_deregister_addr_entry(). Thus a 2nd invocation of
          qeth_set_multicast_list() cannot try to remove the
          same entry twice.

Signed-off-by Ursula Braun <braunu@de.ibm.com>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/s390/net/qeth_main.c b/drivers/s390/net/qeth_main.c
index fe6164795eda..6d7b79e2ba92 100644
--- a/drivers/s390/net/qeth_main.c
+++ b/drivers/s390/net/qeth_main.c
@@ -823,14 +823,15 @@ __qeth_delete_all_mc(struct qeth_card *card, unsigned long *flags)
 again:
         list_for_each_entry_safe(addr, tmp, &card->ip_list, entry) {
                 if (addr->is_multicast) {
+                        list_del(&addr->entry);
                         spin_unlock_irqrestore(&card->ip_lock, *flags);
                         rc = qeth_deregister_addr_entry(card, addr);
                         spin_lock_irqsave(&card->ip_lock, *flags);
                         if (!rc) {
-                                list_del(&addr->entry);
                                 kfree(addr);
                                 goto again;
-                        }
+                        } else
+                                list_add(&addr->entry, &card->ip_list);
                 }
         }
 }