[PATCH] RDMA/siw: Fix a condition race issue in MPA request processing

[Cheng Xu <chengyou@linux.alibaba.com>]

The calling of siw_cm_upcall and detaching new_cep with its
listen_cep should be atomistic semantics. Otherwise siw_reject
may be called in a temporary state, e,g, siw_cm_upcall is called
but the new_cep->listen_cep has not being cleared.

This will generate a WARN in dmesg, which reported in:
https://lore.kernel.org/all/Yliu2ROIh0nLk5l0@bombadil.infradead.org/

Reported-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Cheng Xu <chengyou@linux.alibaba.com>
---
 drivers/infiniband/sw/siw/siw_cm.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/sw/siw/siw_cm.c b/drivers/infiniband/sw/siw/siw_cm.c
index 7acdd3c3a599..17f34d584cd9 100644
--- a/drivers/infiniband/sw/siw/siw_cm.c
+++ b/drivers/infiniband/sw/siw/siw_cm.c
@@ -968,14 +968,15 @@ static void siw_accept_newconn(struct siw_cep *cep)
 
 		siw_cep_set_inuse(new_cep);
 		rv = siw_proc_mpareq(new_cep);
-		siw_cep_set_free(new_cep);
-
 		if (rv != -EAGAIN) {
 			siw_cep_put(cep);
 			new_cep->listen_cep = NULL;
-			if (rv)
+			if (rv) {
+				siw_cep_set_free(new_cep);
 				goto error;
+			}
 		}
+		siw_cep_set_free(new_cep);
 	}
 	return;
 
-- 
2.32.0 (Apple Git-132)