Commit 2239535f authored by Chuck Lever's avatar Chuck Lever
Browse files

svcrdma: Factor out WR chain linking into helper 



svc_rdma_prepare_write_chunk() and svc_rdma_prepare_reply_chunk()
contain identical code for linking RDMA R/W work requests onto a
Send context's WR chain. This duplication increases maintenance
burden and risks divergent bug fixes.

Introduce svc_rdma_cc_link_wrs() to consolidate the WR chain
linking logic. The helper walks the chunk context's rwctxts list,
chains each WR via rdma_rw_ctx_wrs(), and updates the Send
context's chain head and SQE count. Completion signaling is
requested only for the tail WR (posted first).

No functional change.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent d16f060f

net/sunrpc/xprtrdma/svc_rdma_rw.c

+28 −39
Original line number Diff line number Diff line
@@ -619,15 +619,32 @@ static int svc_rdma_xb_write(const struct xdr_buf *xdr, void *data) 
	return xdr->len;

}



/*

 * svc_rdma_prepare_write_chunk - Link Write WRs for @chunk onto @sctxt's chain

 *

 * Write WRs are prepended to the Send WR chain so that a single

 * ib_post_send() posts both RDMA Writes and the final Send. Only

 * the first WR in each chunk gets a CQE for error detection;

 * subsequent WRs complete without individual completion events.

 * The Send WR's signaled completion indicates all chained

 * operations have finished.

/* Link chunk WRs onto @sctxt's WR chain. Completion is requested

 * for the tail WR, which is posted first.

 */

static void svc_rdma_cc_link_wrs(struct svcxprt_rdma *rdma,

				 struct svc_rdma_send_ctxt *sctxt,

				 struct svc_rdma_chunk_ctxt *cc)

{

	struct ib_send_wr *first_wr;

	struct list_head *pos;

	struct ib_cqe *cqe;



	first_wr = sctxt->sc_wr_chain;

	cqe = &cc->cc_cqe;

	list_for_each(pos, &cc->cc_rwctxts) {

		struct svc_rdma_rw_ctxt *rwc;



		rwc = list_entry(pos, struct svc_rdma_rw_ctxt, rw_list);

		first_wr = rdma_rw_ctx_wrs(&rwc->rw_ctx, rdma->sc_qp,

					   rdma->sc_port_num, cqe, first_wr);

		cqe = NULL;

	}

	sctxt->sc_wr_chain = first_wr;

	sctxt->sc_sqecount += cc->cc_sqecount;

}



/* Link Write WRs for @chunk onto @sctxt's WR chain.

 */

static int svc_rdma_prepare_write_chunk(struct svcxprt_rdma *rdma,

					struct svc_rdma_send_ctxt *sctxt,
@@ -636,10 +653,7 @@ static int svc_rdma_prepare_write_chunk(struct svcxprt_rdma *rdma, 
{

	struct svc_rdma_write_info *info;

	struct svc_rdma_chunk_ctxt *cc;

	struct ib_send_wr *first_wr;

	struct xdr_buf payload;

	struct list_head *pos;

	struct ib_cqe *cqe;

	int ret;



	if (xdr_buf_subsegment(xdr, &payload, chunk->ch_position,
@@ -659,18 +673,7 @@ static int svc_rdma_prepare_write_chunk(struct svcxprt_rdma *rdma, 
	if (unlikely(sctxt->sc_sqecount + cc->cc_sqecount > rdma->sc_sq_depth))

		goto out_err;



	first_wr = sctxt->sc_wr_chain;

	cqe = &cc->cc_cqe;

	list_for_each(pos, &cc->cc_rwctxts) {

		struct svc_rdma_rw_ctxt *rwc;



		rwc = list_entry(pos, struct svc_rdma_rw_ctxt, rw_list);

		first_wr = rdma_rw_ctx_wrs(&rwc->rw_ctx, rdma->sc_qp,

					   rdma->sc_port_num, cqe, first_wr);

		cqe = NULL;

	}

	sctxt->sc_wr_chain = first_wr;

	sctxt->sc_sqecount += cc->cc_sqecount;

	svc_rdma_cc_link_wrs(rdma, sctxt, cc);

	list_add(&info->wi_list, &sctxt->sc_write_info_list);



	trace_svcrdma_post_write_chunk(&cc->cc_cid, cc->cc_sqecount);
@@ -732,9 +735,6 @@ int svc_rdma_prepare_reply_chunk(struct svcxprt_rdma *rdma, 
{

	struct svc_rdma_write_info *info = &sctxt->sc_reply_info;

	struct svc_rdma_chunk_ctxt *cc = &info->wi_cc;

	struct ib_send_wr *first_wr;

	struct list_head *pos;

	struct ib_cqe *cqe;

	int ret;



	info->wi_rdma = rdma;
@@ -748,18 +748,7 @@ int svc_rdma_prepare_reply_chunk(struct svcxprt_rdma *rdma, 
	if (ret < 0)

		return ret;



	first_wr = sctxt->sc_wr_chain;

	cqe = &cc->cc_cqe;

	list_for_each(pos, &cc->cc_rwctxts) {

		struct svc_rdma_rw_ctxt *rwc;



		rwc = list_entry(pos, struct svc_rdma_rw_ctxt, rw_list);

		first_wr = rdma_rw_ctx_wrs(&rwc->rw_ctx, rdma->sc_qp,

					   rdma->sc_port_num, cqe, first_wr);

		cqe = NULL;

	}

	sctxt->sc_wr_chain = first_wr;

	sctxt->sc_sqecount += cc->cc_sqecount;

	svc_rdma_cc_link_wrs(rdma, sctxt, cc);



	trace_svcrdma_post_reply_chunk(&cc->cc_cid, cc->cc_sqecount);

	return xdr->len;