From: Yewon Choi woni9911@gmail.com
[ Upstream commit 1422f28826d2a0c11e5240b3e951c9e214d8656e ]
acquire/release_in_xmit() work as bit lock in rds_send_xmit(), so they are expected to ensure acquire/release memory ordering semantics. However, test_and_set_bit/clear_bit() don't imply such semantics, on top of this, following smp_mb__after_atomic() does not guarantee release ordering (memory barrier actually should be placed before clear_bit()).
Instead, we use clear_bit_unlock/test_and_set_bit_lock() here.
Fixes: 0f4b1c7e89e6 ("rds: fix rds_send_xmit() serialization") Fixes: 1f9ecd7eacfd ("RDS: Pass rds_conn_path to rds_send_xmit()") Signed-off-by: Yewon Choi woni9911@gmail.com Reviewed-by: Michal Kubiak michal.kubiak@intel.com Link: https://lore.kernel.org/r/ZfQUxnNTO9AJmzwc@libra05 Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/rds/send.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/net/rds/send.c b/net/rds/send.c index 2899def23865f..09a2801106549 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -103,13 +103,12 @@ EXPORT_SYMBOL_GPL(rds_send_path_reset);
static int acquire_in_xmit(struct rds_conn_path *cp) { - return test_and_set_bit(RDS_IN_XMIT, &cp->cp_flags) == 0; + return test_and_set_bit_lock(RDS_IN_XMIT, &cp->cp_flags) == 0; }
static void release_in_xmit(struct rds_conn_path *cp) { - clear_bit(RDS_IN_XMIT, &cp->cp_flags); - smp_mb__after_atomic(); + clear_bit_unlock(RDS_IN_XMIT, &cp->cp_flags); /* * We don't use wait_on_bit()/wake_up_bit() because our waking is in a * hot path and finding waiters is very rare. We don't want to walk