Re: [PATCH v1 05/12] xprtrdma: Account for RPC/RDMA header size when deciding to inline

Devesh Sharma
2015-07-10T10:55:17Z

Looks good

Reveiwed-By: Devesh Sharma <devesh.sharma-1wcpHE2jlwO1Z/+hSey0Gg@public.gmane.org>

On Fri, Jul 10, 2015 at 2:12 AM, Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
> When marshaling RPC/RDMA requests, ensure the combined size of
> RPC/RDMA header and RPC header do not exceed the inline threshold.
> Endpoints typically reject RPC/RDMA messages that exceed the size
> of their receive buffers.
>
> Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> ---
> net/sunrpc/xprtrdma/rpc_rdma.c | 29 +++++++++++++++++++++++++++--
> 1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
> index 84ea37d..8cf9402 100644
> --- a/net/sunrpc/xprtrdma/rpc_rdma.c
> +++ b/net/sunrpc/xprtrdma/rpc_rdma.c
> @@ -71,6 +71,31 @@ static const char transfertypes[][12] = {
> };
> #endif
>
> +/* The client can send a request inline as long as the RPCRDMA header
> + * plus the RPC call fit under the transport's inline limit. If the
> + * combined call message size exceeds that limit, the client must use
> + * the read chunk list for this operation.
> + */
> +static bool rpcrdma_args_inline(struct rpc_rqst *rqst)
> +{
> + unsigned int callsize = RPCRDMA_HDRLEN_MIN + rqst->rq_snd_buf.len;
> +
> + return callsize <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst);
> +}
> +
> +/* The client can’t know how large the actual reply will be. Thus it
> + * plans for the largest possible reply for that particular ULP
> + * operation. If the maximum combined reply message size exceeds that
> + * limit, the client must provide a write list or a reply chunk for
> + * this request.
> + */
> +static bool rpcrdma_results_inline(struct rpc_rqst *rqst)
> +{
> + unsigned int repsize = RPCRDMA_HDRLEN_MIN + rqst->rq_rcv_buf.buflen;
> +
> + return repsize <= RPCRDMA_INLINE_READ_THRESHOLD(rqst);
> +}
> +
> /*
> * Chunk assembly from upper layer xdr_buf.
> *
> @@ -418,7 +443,7 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
> * a READ, then use write chunks to separate the file data
> * into pages; otherwise use reply chunks.
> */
> - if (rqst->rq_rcv_buf.buflen <= RPCRDMA_INLINE_READ_THRESHOLD(rqst))
> + if (rpcrdma_results_inline(rqst))
> wtype = rpcrdma_noch;
> else if (rqst->rq_rcv_buf.page_len == 0)
> wtype = rpcrdma_replych;
> @@ -441,7 +466,7 @@ rpcrdma_marshal_req(struct rpc_rqst *rqst)
> * implies the op is a write.
> * TBD check NFSv4 setacl
> */
> - if (rqst->rq_snd_buf.len <= RPCRDMA_INLINE_WRITE_THRESHOLD(rqst))
> + if (rpcrdma_args_inline(rqst))
> rtype = rpcrdma_noch;
> else if (rqst->rq_snd_buf.page_len == 0)
> rtype = rpcrdma_areadch;
>
> --
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