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author | Sowmini Varadhan <sowmini.varadhan@oracle.com> | 2018-01-04 17:53:00 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2018-01-05 21:39:18 +0300 |
commit | 3db6e0d172c94bd9953a1347c55ffb64b1d2e74f (patch) | |
tree | 67f61aa4784da3fba56aa43e3626d3f3b6562c78 /net/rds/connection.c | |
parent | c90ecbfaf50d2d7db25c531d9169be7e47435f3f (diff) | |
download | linux-3db6e0d172c94bd9953a1347c55ffb64b1d2e74f.tar.xz |
rds: use RCU to synchronize work-enqueue with connection teardown
rds_sendmsg() can enqueue work on cp_send_w from process context, but
it should not enqueue this work if connection teardown has commenced
(else we risk enquing work after rds_conn_path_destroy() has assumed that
all work has been cancelled/flushed).
Similarly some other functions like rds_cong_queue_updates
and rds_tcp_data_ready are called in softirq context, and may end
up enqueuing work on rds_wq after rds_conn_path_destroy() has assumed
that all workqs are quiesced.
Check the RDS_DESTROY_PENDING bit and use rcu synchronization to avoid
all these races.
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rds/connection.c')
-rw-r--r-- | net/rds/connection.c | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/net/rds/connection.c b/net/rds/connection.c index 1eed197e694f..b10c0ef36d8d 100644 --- a/net/rds/connection.c +++ b/net/rds/connection.c @@ -366,8 +366,6 @@ void rds_conn_shutdown(struct rds_conn_path *cp) * to the conn hash, so we never trigger a reconnect on this * conn - the reconnect is always triggered by the active peer. */ cancel_delayed_work_sync(&cp->cp_conn_w); - if (test_bit(RDS_DESTROY_PENDING, &cp->cp_flags)) - return; rcu_read_lock(); if (!hlist_unhashed(&conn->c_hash_node)) { rcu_read_unlock(); @@ -390,6 +388,7 @@ static void rds_conn_path_destroy(struct rds_conn_path *cp) return; /* make sure lingering queued work won't try to ref the conn */ + synchronize_rcu(); cancel_delayed_work_sync(&cp->cp_send_w); cancel_delayed_work_sync(&cp->cp_recv_w); @@ -407,6 +406,11 @@ static void rds_conn_path_destroy(struct rds_conn_path *cp) if (cp->cp_xmit_rm) rds_message_put(cp->cp_xmit_rm); + WARN_ON(delayed_work_pending(&cp->cp_send_w)); + WARN_ON(delayed_work_pending(&cp->cp_recv_w)); + WARN_ON(delayed_work_pending(&cp->cp_conn_w)); + WARN_ON(work_pending(&cp->cp_down_w)); + cp->cp_conn->c_trans->conn_free(cp->cp_transport_data); } @@ -686,10 +690,13 @@ void rds_conn_path_drop(struct rds_conn_path *cp, bool destroy) { atomic_set(&cp->cp_state, RDS_CONN_ERROR); - if (!destroy && test_bit(RDS_DESTROY_PENDING, &cp->cp_flags)) + rcu_read_lock(); + if (!destroy && test_bit(RDS_DESTROY_PENDING, &cp->cp_flags)) { + rcu_read_unlock(); return; - + } queue_work(rds_wq, &cp->cp_down_w); + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(rds_conn_path_drop); @@ -706,9 +713,15 @@ EXPORT_SYMBOL_GPL(rds_conn_drop); */ void rds_conn_path_connect_if_down(struct rds_conn_path *cp) { + rcu_read_lock(); + if (test_bit(RDS_DESTROY_PENDING, &cp->cp_flags)) { + rcu_read_unlock(); + return; + } if (rds_conn_path_state(cp) == RDS_CONN_DOWN && !test_and_set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags)) queue_delayed_work(rds_wq, &cp->cp_conn_w, 0); + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(rds_conn_path_connect_if_down); |