| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.10 156/167] xprtrdma: Fix Read chunk padding | Date | Fri, 10 Mar 2017 10:09:59 +0100 |
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4.10-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever <chuck.lever@oracle.com>
commit 24abdf1be15c478e2821d6fc903a4a4440beff02 upstream.
When pad optimization is disabled, rpcrdma_convert_iovs still does not add explicit XDR round-up padding to a Read chunk.
Commit 677eb17e94ed ("xprtrdma: Fix XDR tail buffer marshalling") incorrectly short-circuited the test for whether round-up padding is needed that appears later in rpcrdma_convert_iovs.
However, if this is indeed a regular Read chunk (and not a Position-Zero Read chunk), the tail iovec _always_ contains the chunk's padding, and never anything else.
So, it's easy to just skip the tail when padding optimization is enabled, and add the tail in a subsequent Read chunk segment, if disabled.
Fixes: 677eb17e94ed ("xprtrdma: Fix XDR tail buffer marshalling") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- net/sunrpc/xprtrdma/rpc_rdma.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
--- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -226,8 +226,10 @@ rpcrdma_convert_iovs(struct xdr_buf *xdr if (len && n == RPCRDMA_MAX_SEGS) goto out_overflow; - /* When encoding the read list, the tail is always sent inline */ - if (type == rpcrdma_readch) + /* When encoding a Read chunk, the tail iovec contains an + * XDR pad and may be omitted. + */ + if (type == rpcrdma_readch && xprt_rdma_pad_optimize) return n; /* When encoding the Write list, some servers need to see an extra @@ -238,10 +240,6 @@ rpcrdma_convert_iovs(struct xdr_buf *xdr return n; if (xdrbuf->tail[0].iov_len) { - /* the rpcrdma protocol allows us to omit any trailing - * xdr pad bytes, saving the server an RDMA operation. */ - if (xdrbuf->tail[0].iov_len < 4 && xprt_rdma_pad_optimize) - return n; n = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, n); if (n == RPCRDMA_MAX_SEGS) goto out_overflow;
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