xprtrdma: Prevent inline overflow
When deciding whether to send a Call inline, rpcrdma_marshal_req doesn't take into account header bytes consumed by chunk lists. This results in Call messages on the wire that are sometimes larger than the inline threshold. Likewise, when a Write list or Reply chunk is in play, the server's reply has to emit an RDMA Send that includes a larger-than-minimal RPC-over-RDMA header. The actual size of a Call message cannot be estimated until after the chunk lists have been registered. Thus the size of each RPC-over-RDMA header can be estimated only after chunks are registered; but the decision to register chunks is based on the size of that header. Chicken, meet egg. The best a client can do is estimate header size based on the largest header that might occur, and then ensure that inline content is always smaller than that. Signed-off-by:Chuck Lever <chuck.lever@oracle.com> Tested-by:
Steve Wise <swise@opengridcomputing.com> Signed-off-by:
Anna Schumaker <Anna.Schumaker@Netapp.com>
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