RDMA core mutex locking was restructured by d114c6feedfe ("RDMA/cma:
Add missing locking to rdma_accept()") [Aug 2020]. When lock
debugging is enabled, the RPC/RDMA server trips over the new lockdep
assertion in rdma_accept() because it doesn't call rdma_accept()
from its CM event handler.
As a temporary fix, have svc_rdma_accept() take the mutex
explicitly. In the meantime, let's consider how to restructure the
RPC/RDMA transport to invoke rdma_accept() from the proper context.
Calls to svc_rdma_accept() are serialized with calls to
svc_rdma_free() by the generic RPC server layer.
Suggested-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/svc_rdma_transport.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index afba4e9d5425..8d14dbd45418 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -498,7 +498,9 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
}
conn_param.private_data = &pmsg;
conn_param.private_data_len = sizeof(pmsg);
+ rdma_lock_handler(newxprt->sc_cm_id);
ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
+ rdma_unlock_handler(newxprt->sc_cm_id);
if (ret) {
trace_svcrdma_accept_err(newxprt, ret);
goto errout;
