From 552bf225281f96e7a02e1a1b874966fdb6b997e0 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 4 Mar 2016 11:28:36 -0500 Subject: [PATCH] xprtrdma: Use new CQ API for RPC-over-RDMA client receive CQs Calling ib_poll_cq() to sort through WCs during a completion is a common pattern amongst RDMA consumers. Since commit 14d3a3b2498e ("IB: add a proper completion queue abstraction"), WC sorting can be handled by the IB core. By converting to this new API, xprtrdma is made a better neighbor to other RDMA consumers, as it allows the core to schedule the delivery of completions more fairly amongst all active consumers. Because each ib_cqe carries a pointer to a completion method, the core can now post its own operations on a consumer's QP, and handle the completions itself, without changes to the consumer. xprtrdma's reply processing is already handled in a work queue, but there is some initial order-dependent processing that is done in the soft IRQ context before a work item is scheduled. IB_POLL_SOFTIRQ is a direct replacement for the current xprtrdma receive code path. Signed-off-by: Chuck Lever Reviewed-by: Devesh Sharma Reviewed-by: Sagi Grimberg Signed-off-by: Anna Schumaker --- net/sunrpc/xprtrdma/verbs.c | 78 +++++++++------------------------ net/sunrpc/xprtrdma/xprt_rdma.h | 1 + 2 files changed, 21 insertions(+), 58 deletions(-) diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index fc1ef5f144b8..05779f48745b 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -212,11 +212,18 @@ rpcrdma_update_granted_credits(struct rpcrdma_rep *rep) atomic_set(&buffer->rb_credits, credits); } +/** + * rpcrdma_receive_wc - Invoked by RDMA provider for each polled Receive WC + * @cq: completion queue (ignored) + * @wc: completed WR + * + */ static void -rpcrdma_recvcq_process_wc(struct ib_wc *wc) +rpcrdma_receive_wc(struct ib_cq *cq, struct ib_wc *wc) { - struct rpcrdma_rep *rep = - (struct rpcrdma_rep *)(unsigned long)wc->wr_id; + struct ib_cqe *cqe = wc->wr_cqe; + struct rpcrdma_rep *rep = container_of(cqe, struct rpcrdma_rep, + rr_cqe); /* WARNING: Only wr_id and status are reliable at this point */ if (wc->status != IB_WC_SUCCESS) @@ -242,55 +249,20 @@ out_schedule: out_fail: if (wc->status != IB_WC_WR_FLUSH_ERR) - pr_err("RPC: %s: rep %p: %s\n", - __func__, rep, ib_wc_status_msg(wc->status)); + pr_err("rpcrdma: Recv: %s (%u/0x%x)\n", + ib_wc_status_msg(wc->status), + wc->status, wc->vendor_err); rep->rr_len = RPCRDMA_BAD_LEN; goto out_schedule; } -/* The wc array is on stack: automatic memory is always CPU-local. - * - * struct ib_wc is 64 bytes, making the poll array potentially - * large. But this is at the bottom of the call chain. Further - * substantial work is done in another thread. - */ -static void -rpcrdma_recvcq_poll(struct ib_cq *cq) -{ - struct ib_wc *pos, wcs[4]; - int count, rc; - - do { - pos = wcs; - - rc = ib_poll_cq(cq, ARRAY_SIZE(wcs), pos); - if (rc < 0) - break; - - count = rc; - while (count-- > 0) - rpcrdma_recvcq_process_wc(pos++); - } while (rc == ARRAY_SIZE(wcs)); -} - -/* Handle provider receive completion upcalls. - */ -static void -rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context) -{ - do { - rpcrdma_recvcq_poll(cq); - } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP | - IB_CQ_REPORT_MISSED_EVENTS) > 0); -} - static void rpcrdma_flush_cqs(struct rpcrdma_ep *ep) { struct ib_wc wc; while (ib_poll_cq(ep->rep_attr.recv_cq, 1, &wc) > 0) - rpcrdma_recvcq_process_wc(&wc); + rpcrdma_receive_wc(NULL, &wc); while (ib_poll_cq(ep->rep_attr.send_cq, 1, &wc) > 0) rpcrdma_sendcq_process_wc(&wc); } @@ -655,9 +627,9 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, goto out2; } - cq_attr.cqe = ep->rep_attr.cap.max_recv_wr + 1; - recvcq = ib_create_cq(ia->ri_device, rpcrdma_recvcq_upcall, - rpcrdma_cq_async_error_upcall, NULL, &cq_attr); + recvcq = ib_alloc_cq(ia->ri_device, NULL, + ep->rep_attr.cap.max_recv_wr + 1, + 0, IB_POLL_SOFTIRQ); if (IS_ERR(recvcq)) { rc = PTR_ERR(recvcq); dprintk("RPC: %s: failed to create recv CQ: %i\n", @@ -665,14 +637,6 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, goto out2; } - rc = ib_req_notify_cq(recvcq, IB_CQ_NEXT_COMP); - if (rc) { - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", - __func__, rc); - ib_destroy_cq(recvcq); - goto out2; - } - ep->rep_attr.send_cq = sendcq; ep->rep_attr.recv_cq = recvcq; @@ -735,10 +699,7 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) ia->ri_id->qp = NULL; } - rc = ib_destroy_cq(ep->rep_attr.recv_cq); - if (rc) - dprintk("RPC: %s: ib_destroy_cq returned %i\n", - __func__, rc); + ib_free_cq(ep->rep_attr.recv_cq); rc = ib_destroy_cq(ep->rep_attr.send_cq); if (rc) @@ -947,6 +908,7 @@ rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt) } rep->rr_device = ia->ri_device; + rep->rr_cqe.done = rpcrdma_receive_wc; rep->rr_rxprt = r_xprt; INIT_WORK(&rep->rr_work, rpcrdma_receive_worker); return rep; @@ -1322,7 +1284,7 @@ rpcrdma_ep_post_recv(struct rpcrdma_ia *ia, int rc; recv_wr.next = NULL; - recv_wr.wr_id = (u64) (unsigned long) rep; + recv_wr.wr_cqe = &rep->rr_cqe; recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov; recv_wr.num_sge = 1; diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 7bf6f43fa4b9..d60feb9aa631 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -171,6 +171,7 @@ rdmab_to_msg(struct rpcrdma_regbuf *rb) struct rpcrdma_buffer; struct rpcrdma_rep { + struct ib_cqe rr_cqe; unsigned int rr_len; struct ib_device *rr_device; struct rpcrdma_xprt *rr_rxprt; -- 2.20.1