On Tue, May 26, 2015 at 01:48:37PM -0400, Chuck Lever wrote:
> In send_write_chunks(), we have:
>
> for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
> xfer_len && chunk_no < arg_ary->wc_nchunks;
> chunk_no++) {
> . . .
> }
>
> Note that arg_ary->wc_nchunk is in network byte-order. For the
> comparison to work correctly, both have to be in native byte-order.
>
> In send_reply_chunks, we have:
>
> write_len = min(xfer_len, htonl(ch->rs_length));
>
> xfer_len is in native byte-order, and ch->rs_length is in
> network byte-order. be32_to_cpu() is the correct byte swap
> for ch->rs_length.
>
> As an additional clean up, replace ntohl() with be32_to_cpu() in
> a few other places.
Why? (Not arguing, really, just wondering.)
--b.
>
> This appears to address a problem with large rsize hangs while
> using PHYSICAL memory registration. I suspect that is the only
> registration mode that uses more than one chunk element.
>
> BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=248
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
>
> net/sunrpc/xprtrdma/svc_rdma_sendto.c | 14 ++++++++------
> 1 files changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> index 7de33d1..109e967 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> @@ -240,6 +240,7 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
> u32 xdr_off;
> int chunk_off;
> int chunk_no;
> + int nchunks;
> struct rpcrdma_write_array *arg_ary;
> struct rpcrdma_write_array *res_ary;
> int ret;
> @@ -251,14 +252,15 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
> &rdma_resp->rm_body.rm_chunks[1];
>
> /* Write chunks start at the pagelist */
> + nchunks = be32_to_cpu(arg_ary->wc_nchunks);
> for (xdr_off = rqstp->rq_res.head[0].iov_len, chunk_no = 0;
> - xfer_len && chunk_no < arg_ary->wc_nchunks;
> + xfer_len && chunk_no < nchunks;
> chunk_no++) {
> struct rpcrdma_segment *arg_ch;
> u64 rs_offset;
>
> arg_ch = &arg_ary->wc_array[chunk_no].wc_target;
> - write_len = min(xfer_len, ntohl(arg_ch->rs_length));
> + write_len = min(xfer_len, be32_to_cpu(arg_ch->rs_length));
>
> /* Prepare the response chunk given the length actually
> * written */
> @@ -270,7 +272,7 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
> chunk_off = 0;
> while (write_len) {
> ret = send_write(xprt, rqstp,
> - ntohl(arg_ch->rs_handle),
> + be32_to_cpu(arg_ch->rs_handle),
> rs_offset + chunk_off,
> xdr_off,
> write_len,
> @@ -318,13 +320,13 @@ static int send_reply_chunks(struct svcxprt_rdma *xprt,
> &rdma_resp->rm_body.rm_chunks[2];
>
> /* xdr offset starts at RPC message */
> - nchunks = ntohl(arg_ary->wc_nchunks);
> + nchunks = be32_to_cpu(arg_ary->wc_nchunks);
> for (xdr_off = 0, chunk_no = 0;
> xfer_len && chunk_no < nchunks;
> chunk_no++) {
> u64 rs_offset;
> ch = &arg_ary->wc_array[chunk_no].wc_target;
> - write_len = min(xfer_len, htonl(ch->rs_length));
> + write_len = min(xfer_len, be32_to_cpu(ch->rs_length));
>
> /* Prepare the reply chunk given the length actually
> * written */
> @@ -335,7 +337,7 @@ static int send_reply_chunks(struct svcxprt_rdma *xprt,
> chunk_off = 0;
> while (write_len) {
> ret = send_write(xprt, rqstp,
> - ntohl(ch->rs_handle),
> + be32_to_cpu(ch->rs_handle),
> rs_offset + chunk_off,
> xdr_off,
> write_len,
--
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