diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2021-10-05 16:17:59 +0200 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2021-10-21 00:09:54 +0200 |
| commit | 21037b8c2258ec40de3b31be9ced43ceb3b784f7 (patch) | |
| tree | c574cc4e7901a1611311432edd6b8d4ea398c6b8 /net/sunrpc/xprtrdma/rpc_rdma.c | |
| parent | Fix user namespace leak (diff) | |
| download | linux-21037b8c2258ec40de3b31be9ced43ceb3b784f7.tar.xz linux-21037b8c2258ec40de3b31be9ced43ceb3b784f7.zip | |
xprtrdma: Provide a buffer to pad Write chunks of unaligned length
This is a buffer to be left persistently registered while a
connection is up. Connection tear-down will automatically DMA-unmap,
invalidate, and dereg the MR. A persistently registered buffer is
lower in cost to provide, and it can never be coalesced into the
RDMA segment that carries the data payload.
An RPC that provisions a Write chunk with a non-aligned length now
uses this MR rather than the tail buffer of the RPC's rq_rcv_buf.
Reviewed-By: Tom Talpey <tom@talpey.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'net/sunrpc/xprtrdma/rpc_rdma.c')
| -rw-r--r-- | net/sunrpc/xprtrdma/rpc_rdma.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index c335c1361564..8035a983c8ce 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -255,15 +255,7 @@ rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf, page_base = 0; } - if (type == rpcrdma_readch) - goto out; - - /* When encoding a Write chunk, some servers need to see an - * extra segment for non-XDR-aligned Write chunks. The upper - * layer provides space in the tail iovec that may be used - * for this purpose. - */ - if (type == rpcrdma_writech && r_xprt->rx_ep->re_implicit_roundup) + if (type == rpcrdma_readch || type == rpcrdma_writech) goto out; if (xdrbuf->tail[0].iov_len) @@ -405,6 +397,7 @@ static int rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, enum rpcrdma_chunktype wtype) { struct xdr_stream *xdr = &req->rl_stream; + struct rpcrdma_ep *ep = r_xprt->rx_ep; struct rpcrdma_mr_seg *seg; struct rpcrdma_mr *mr; int nsegs, nchunks; @@ -443,6 +436,18 @@ static int rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, nsegs -= mr->mr_nents; } while (nsegs); + if (xdr_pad_size(rqst->rq_rcv_buf.page_len)) { + if (encode_rdma_segment(xdr, ep->re_write_pad_mr) < 0) + return -EMSGSIZE; + + trace_xprtrdma_chunk_wp(rqst->rq_task, ep->re_write_pad_mr, + nsegs); + r_xprt->rx_stats.write_chunk_count++; + r_xprt->rx_stats.total_rdma_request += mr->mr_length; + nchunks++; + nsegs -= mr->mr_nents; + } + /* Update count of segments in this Write chunk */ *segcount = cpu_to_be32(nchunks); |