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| author |   Chuck Lever <chuck.lever@oracle.com> | 2021-02-09 10:48:57 -0500 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2021-02-15 10:45:00 -0500 |
| commit | 0ac24c320c4d89a9de6ec802591398b8675c7b3c (patch) | |
| tree | 028e11f7256f1d549a261cd7292ed2126225021a /net | |
| parent | nfsd: register pernet ops last, unregister first (diff) | |
| download | linux-dev-0ac24c320c4d89a9de6ec802591398b8675c7b3c.tar.xz linux-dev-0ac24c320c4d89a9de6ec802591398b8675c7b3c.zip | |
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.c | 6 |
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; |