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authorChuck Lever <chuck.lever@oracle.com>2021-02-09 10:48:57 -0500
committerChuck Lever <chuck.lever@oracle.com>2021-02-15 10:45:00 -0500
commit0ac24c320c4d89a9de6ec802591398b8675c7b3c (patch)
tree028e11f7256f1d549a261cd7292ed2126225021a /net
parentbd5ae9288d6451bd346a1b4a59d4fe7e62ba29b7 (diff)
svcrdma: Hold private mutex while invoking rdma_accept()
RDMA core mutex locking was restructured by commit 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 handler_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@nvidia.com> Link: https://lore.kernel.org/linux-rdma/20210209154014.GO4247@nvidia.com/ Fixes: d114c6feedfe ("RDMA/cma: Add missing locking to rdma_accept()") Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'net')
-rw-r--r--net/sunrpc/xprtrdma/svc_rdma_transport.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index afba4e9d5425..c895f80df659 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -475,9 +475,6 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
if (!svc_rdma_post_recvs(newxprt))
goto errout;
- /* Swap out the handler */
- newxprt->sc_cm_id->event_handler = svc_rdma_cma_handler;
-
/* Construct RDMA-CM private message */
pmsg.cp_magic = rpcrdma_cmp_magic;
pmsg.cp_version = RPCRDMA_CMP_VERSION;
@@ -498,7 +495,10 @@ 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);
+ newxprt->sc_cm_id->event_handler = svc_rdma_cma_handler;
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;