[PATCH 5.10 100/147] svcrdma: Add a batch Receive posting mechanism

Sasha Levin
2026-02-28T18:18:56Z

From: Chuck Lever <chuck.lever@oracle.com>

[ Upstream commit 77f0a2aa5cdde0524eab745f7a117706d3e3014f ]

Introduce a server-side mechanism similar to commit e340c2d6ef2a
("xprtrdma: Reduce the doorbell rate (Receive)") to post Receive
WRs in batch. Its first consumer is svc_rdma_post_recvs(), which
posts the initial set of Receive WRs.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Stable-dep-of: afcae7d7b8a2 ("RDMA/core: add rdma_rw_max_sge() helper for SQ sizing")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 56 ++++++++++++++++++-------
1 file changed, 42 insertions(+), 14 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index c6ea2903c21a4..4129a2d5cc715 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -252,6 +252,47 @@ void svc_rdma_release_rqst(struct svc_rqst *rqstp)
svc_rdma_recv_ctxt_put(rdma, ctxt);
}

+static bool svc_rdma_refresh_recvs(struct svcxprt_rdma *rdma,
+ unsigned int wanted, bool temp)
+{
+ const struct ib_recv_wr *bad_wr = NULL;
+ struct svc_rdma_recv_ctxt *ctxt;
+ struct ib_recv_wr *recv_chain;
+ int ret;
+
+ if (test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags))
+ return false;
+
+ recv_chain = NULL;
+ while (wanted--) {
+ ctxt = svc_rdma_recv_ctxt_get(rdma);
+ if (!ctxt)
+ break;
+
+ trace_svcrdma_post_recv(ctxt);
+ ctxt->rc_temp = temp;
+ ctxt->rc_recv_wr.next = recv_chain;
+ recv_chain = &ctxt->rc_recv_wr;
+ }
+ if (!recv_chain)
+ return false;
+
+ ret = ib_post_recv(rdma->sc_qp, recv_chain, &bad_wr);
+ if (ret)
+ goto err_free;
+ return true;
+
+err_free:
+ trace_svcrdma_rq_post_err(rdma, ret);
+ while (bad_wr) {
+ ctxt = container_of(bad_wr, struct svc_rdma_recv_ctxt,
+ rc_recv_wr);
+ bad_wr = bad_wr->next;
+ svc_rdma_recv_ctxt_put(rdma, ctxt);
+ }
+ return false;
+}
+
static int __svc_rdma_post_recv(struct svcxprt_rdma *rdma,
struct svc_rdma_recv_ctxt *ctxt)
{
@@ -289,20 +330,7 @@ static int svc_rdma_post_recv(struct svcxprt_rdma *rdma)
*/
bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma)
{
- struct svc_rdma_recv_ctxt *ctxt;
- unsigned int i;
- int ret;
-
- for (i = 0; i < rdma->sc_max_requests; i++) {
- ctxt = svc_rdma_recv_ctxt_get(rdma);
- if (!ctxt)
- return false;
- ctxt->rc_temp = true;
- ret = __svc_rdma_post_recv(rdma, ctxt);
- if (ret)
- return false;
- }
- return true;
+ return svc_rdma_refresh_recvs(rdma, rdma->sc_max_requests, true);
}

/**
--
2.51.0