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 <chuck.lever@xxxxxxxxxx> --- net/sunrpc/xprtrdma/frwr_ops.c | 7 +++++-- net/sunrpc/xprtrdma/transport.c | 6 ++++-- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c index fc6378cc..ae94de9 100644 --- a/net/sunrpc/xprtrdma/frwr_ops.c +++ b/net/sunrpc/xprtrdma/frwr_ops.c @@ -242,7 +242,10 @@ 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; } @@ -255,7 +258,7 @@ 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 ae2a838..2ba8be1 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -696,8 +696,10 @@ * %-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)
