Commit ecba85e9 authored by Chuck Lever's avatar Chuck Lever
Browse files

svcrdma: Copy construction of svc_rqst::rq_arg to rdma_read_complete() 



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: default avatarChuck Lever <chuck.lever@oracle.com>
parent a937693a

include/trace/events/rpcrdma.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

+92 −1
Original line number Diff line number Diff line
@@ -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);

}



/**