[PATCH net-next 2/4] net/smc: lock smc_lgr_list in port_terminate()

Ursula Braun
2018-05-23T14:38:10Z

From: Hans Wippel <hwippel@linux.ibm.com>

Currently, smc_port_terminate() is not holding the lock of the lgr list
while it is traversing the list. This patch adds locking to this
function and changes smc_lgr_terminate() accordingly.

Signed-off-by: Hans Wippel <hwippel@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
---
net/smc/smc_core.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 1e5c0e90a706..21c244f53b0a 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -346,7 +346,7 @@ void smc_lgr_forget(struct smc_link_group *lgr)
}

/* terminate linkgroup abnormally */
-void smc_lgr_terminate(struct smc_link_group *lgr)
+static void __smc_lgr_terminate(struct smc_link_group *lgr)
{
struct smc_connection *conn;
struct smc_sock *smc;
@@ -355,7 +355,8 @@ void smc_lgr_terminate(struct smc_link_group *lgr)
if (lgr->terminating)
return; /* lgr already terminating */
lgr->terminating = 1;
- smc_lgr_forget(lgr);
+ if (!list_empty(&lgr->list)) /* forget lgr */
+ list_del_init(&lgr->list);
smc_llc_link_inactive(&lgr->lnk[SMC_SINGLE_LINK]);

write_lock_bh(&lgr->conns_lock);
@@ -377,16 +378,25 @@ void smc_lgr_terminate(struct smc_link_group *lgr)
smc_lgr_schedule_free_work(lgr);
}

+void smc_lgr_terminate(struct smc_link_group *lgr)
+{
+ spin_lock_bh(&smc_lgr_list.lock);
+ __smc_lgr_terminate(lgr);
+ spin_unlock_bh(&smc_lgr_list.lock);
+}
+
/* Called when IB port is terminated */
void smc_port_terminate(struct smc_ib_device *smcibdev, u8 ibport)
{
struct smc_link_group *lgr, *l;

+ spin_lock_bh(&smc_lgr_list.lock);
list_for_each_entry_safe(lgr, l, &smc_lgr_list.list, list) {
if (lgr->lnk[SMC_SINGLE_LINK].smcibdev == smcibdev &&
lgr->lnk[SMC_SINGLE_LINK].ibport == ibport)
- smc_lgr_terminate(lgr);
+ __smc_lgr_terminate(lgr);
}
+ spin_unlock_bh(&smc_lgr_list.lock);
}

/* Determine vlan of internal TCP socket.
--
2.16.3