From: Chuck Lever <chuck.lever@xxxxxxxxxx>
Once a set of RDMA Reads are complete, the Read completion handler
will poke the transport to trigger a second call to
svc_rdma_recvfrom(). recvfrom() will then merge the RDMA Read
payloads with the previously received RPC header to form a completed
RPC Call message.
The new code is copied from the svc_rdma_process_read_list() path.
A subsequent patch will make use of this code and remove the code
that this was copied from (svc_rdma_rw.c).
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/trace/events/rpcrdma.h | 1
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 93 +++++++++++++++++++++++++++++++
2 files changed, 93 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/rpcrdma.h b/include/trace/events/rpcrdma.h
index 9a3fc6eb09a8..110c1475c527 100644
--- a/include/trace/events/rpcrdma.h
+++ b/include/trace/events/rpcrdma.h
@@ -2112,6 +2112,7 @@ TRACE_EVENT(svcrdma_wc_read,
DEFINE_SEND_FLUSH_EVENT(svcrdma_wc_read_flush);
DEFINE_SEND_FLUSH_EVENT(svcrdma_wc_read_err);
+DEFINE_SIMPLE_CID_EVENT(svcrdma_read_finished);
DEFINE_SIMPLE_CID_EVENT(svcrdma_wc_write);
DEFINE_SEND_FLUSH_EVENT(svcrdma_wc_write_flush);
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 2de947183a7a..034bdd02f925 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -767,10 +767,86 @@ static bool svc_rdma_is_reverse_direction_reply(struct svc_xprt *xprt,
return true;
}
+/* Finish constructing the RPC Call message in rqstp::rq_arg.
+ *
+ * The incoming RPC/RDMA message is an RDMA_MSG type message
+ * with a single Read chunk (only the upper layer data payload
+ * was conveyed via RDMA Read).
+ */
+static void svc_rdma_read_complete_one(struct svc_rqst *rqstp,
+ struct svc_rdma_recv_ctxt *ctxt)
+{
+ struct svc_rdma_chunk *chunk = pcl_first_chunk(&ctxt->rc_read_pcl);
+ struct xdr_buf *buf = &rqstp->rq_arg;
+ unsigned int length;
+
+ /* Split the Receive buffer between the head and tail
+ * buffers at Read chunk's position. XDR roundup of the
+ * chunk is not included in either the pagelist or in
+ * the tail.
+ */
+ buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position;
+ buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position;
+ buf->head[0].iov_len = chunk->ch_position;
+
+ /* Read chunk may need XDR roundup (see RFC 8166, s. 3.4.5.2).
+ *
+ * If the client already rounded up the chunk length, the
+ * length does not change. Otherwise, the length of the page
+ * list is increased to include XDR round-up.
+ *
+ * Currently these chunks always start at page offset 0,
+ * thus the rounded-up length never crosses a page boundary.
+ */
+ buf->pages = &rqstp->rq_pages[0];
+ length = xdr_align_size(chunk->ch_length);
+ buf->page_len = length;
+ buf->len += length;
+ buf->buflen += length;
+}
+
+/* Finish constructing the RPC Call message in rqstp::rq_arg.
+ *
+ * The incoming RPC/RDMA message is an RDMA_MSG type message
+ * with payload in multiple Read chunks and no PZRC.
+ */
+static void svc_rdma_read_complete_multiple(struct svc_rqst *rqstp,
+ struct svc_rdma_recv_ctxt *ctxt)
+{
+ struct xdr_buf *buf = &rqstp->rq_arg;
+
+ buf->len += ctxt->rc_readbytes;
+ buf->buflen += ctxt->rc_readbytes;
+
+ buf->head[0].iov_base = page_address(rqstp->rq_pages[0]);
+ buf->head[0].iov_len = min_t(size_t, PAGE_SIZE, ctxt->rc_readbytes);
+ buf->pages = &rqstp->rq_pages[1];
+ buf->page_len = ctxt->rc_readbytes - buf->head[0].iov_len;
+}
+
+/* Finish constructing the RPC Call message in rqstp::rq_arg.
+ *
+ * The incoming RPC/RDMA message is an RDMA_NOMSG type message
+ * (the RPC message body was conveyed via RDMA Read).
+ */
+static void svc_rdma_read_complete_pzrc(struct svc_rqst *rqstp,
+ struct svc_rdma_recv_ctxt *ctxt)
+{
+ struct xdr_buf *buf = &rqstp->rq_arg;
+
+ buf->len += ctxt->rc_readbytes;
+ buf->buflen += ctxt->rc_readbytes;
+
+ buf->head[0].iov_base = page_address(rqstp->rq_pages[0]);
+ buf->head[0].iov_len = min_t(size_t, PAGE_SIZE, ctxt->rc_readbytes);
+ buf->pages = &rqstp->rq_pages[1];
+ buf->page_len = ctxt->rc_readbytes - buf->head[0].iov_len;
+}
+
static noinline void svc_rdma_read_complete(struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *ctxt)
{
- int i;
+ unsigned int i;
/* Transfer the Read chunk pages into @rqstp.rq_pages, replacing
* the rq_pages that were already allocated for this rqstp.
@@ -789,6 +865,21 @@ static noinline void svc_rdma_read_complete(struct svc_rqst *rqstp,
* pages in ctxt::rc_pages a second time.
*/
ctxt->rc_page_count = 0;
+
+ /* Finish constructing the RPC Call message. The exact
+ * procedure for that depends on what kind of RPC/RDMA
+ * chunks were provided by the client.
+ */
+ if (pcl_is_empty(&ctxt->rc_call_pcl)) {
+ if (ctxt->rc_read_pcl.cl_count == 1)
+ svc_rdma_read_complete_one(rqstp, ctxt);
+ else
+ svc_rdma_read_complete_multiple(rqstp, ctxt);
+ } else {
+ svc_rdma_read_complete_pzrc(rqstp, ctxt);
+ }
+
+ trace_svcrdma_read_finished(&ctxt->rc_cid);
}
/**
