From 6946f82380a83acb7023fab9d7033e1f016cb818 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Wed, 19 Dec 2018 10:58:45 -0500 Subject: [PATCH] xprtrdma: Fix ri_max_segs and the result of ro_maxpages With certain combinations of krb5i/p, MR size, and r/wsize, I/O can fail with EMSGSIZE. This is because the calculated value of ri_max_segs (the max number of MRs per RPC) exceeded RPCRDMA_MAX_HDR_SEGS, which caused Read or Write list encoding to walk off the end of the transport header. Once that was addressed, the ro_maxpages result has to be corrected to account for the number of MRs needed for Reply chunks, which is 2 MRs smaller than a normal Read or Write chunk. Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker --- net/sunrpc/xprtrdma/fmr_ops.c | 7 +++++-- net/sunrpc/xprtrdma/frwr_ops.c | 7 +++++-- net/sunrpc/xprtrdma/transport.c | 6 ++++-- 3 files changed, 14 insertions(+), 6 deletions(-) diff --git a/net/sunrpc/xprtrdma/fmr_ops.c b/net/sunrpc/xprtrdma/fmr_ops.c index 7f5632cd5a48..dd1e91bd8ef8 100644 --- a/net/sunrpc/xprtrdma/fmr_ops.c +++ b/net/sunrpc/xprtrdma/fmr_ops.c @@ -176,7 +176,10 @@ fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS / RPCRDMA_MAX_FMR_SGES); - ia->ri_max_segs += 2; /* segments for head and tail buffers */ + /* Reply chunks require segments for head and tail buffers */ + ia->ri_max_segs += 2; + if (ia->ri_max_segs > RPCRDMA_MAX_HDR_SEGS) + ia->ri_max_segs = RPCRDMA_MAX_HDR_SEGS; return 0; } @@ -186,7 +189,7 @@ static size_t fmr_op_maxpages(struct rpcrdma_xprt *r_xprt) { return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS, - RPCRDMA_MAX_HDR_SEGS * RPCRDMA_MAX_FMR_SGES); + (r_xprt->rx_ia.ri_max_segs - 2) * RPCRDMA_MAX_FMR_SGES); } /* Use the ib_map_phys_fmr() verb to register a memory region diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c index 27222c034ad2..f587e445d811 100644 --- a/net/sunrpc/xprtrdma/frwr_ops.c +++ b/net/sunrpc/xprtrdma/frwr_ops.c @@ -244,7 +244,10 @@ frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS / ia->ri_max_frwr_depth); - ia->ri_max_segs += 2; /* segments for head and tail buffers */ + /* Reply chunks require segments for head and tail buffers */ + ia->ri_max_segs += 2; + if (ia->ri_max_segs > RPCRDMA_MAX_HDR_SEGS) + ia->ri_max_segs = RPCRDMA_MAX_HDR_SEGS; return 0; } @@ -257,7 +260,7 @@ frwr_op_maxpages(struct rpcrdma_xprt *r_xprt) struct rpcrdma_ia *ia = &r_xprt->rx_ia; return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS, - RPCRDMA_MAX_HDR_SEGS * ia->ri_max_frwr_depth); + (ia->ri_max_segs - 2) * ia->ri_max_frwr_depth); } static void diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index 134aae2ee779..d3f26c570067 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -703,8 +703,10 @@ xprt_rdma_free(struct rpc_task *task) * %-ENOTCONN if the caller should reconnect and call again * %-EAGAIN if the caller should call again * %-ENOBUFS if the caller should call again after a delay - * %-EIO if a permanent error occurred and the request was not - * sent. Do not try to send this message again. + * %-EMSGSIZE if encoding ran out of buffer space. The request + * was not sent. Do not try to send this message again. + * %-EIO if an I/O error occurred. The request was not sent. + * Do not try to send this message again. */ static int xprt_rdma_send_request(struct rpc_rqst *rqst) -- 2.39.5