From d792459a6e2ae21c7f5107babd63e52e4c5ab93a Mon Sep 17 00:00:00 2001 From: Yewon Choi Date: Fri, 15 Mar 2024 18:28:38 +0900 Subject: rds: introduce acquire/release ordering in acquire/release_in_xmit() [ 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 Reviewed-by: Michal Kubiak Link: https://lore.kernel.org/r/ZfQUxnNTO9AJmzwc@libra05 Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/rds/send.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/net/rds/send.c b/net/rds/send.c index 2899def23865..09a280110654 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 -- cgit v1.2.3