/* * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved. * * This software is available to you under a choice of one of two * licenses. You may choose to be licensed under the terms of the GNU * General Public License (GPL) Version 2, available from the file * COPYING in the main directory of this source tree, or the BSD-type * license below: * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * * Neither the name of the Network Appliance, Inc. nor the names of * its contributors may be used to endorse or promote products * derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * verbs.c * * Encapsulates the major functions managing: * o adapters * o endpoints * o connections * o buffer memory */ #include #include #include #include #include #include #include #include #include "xprt_rdma.h" /* * Globals/Macros */ #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) # define RPCDBG_FACILITY RPCDBG_TRANS #endif /* * internal functions */ static void rpcrdma_create_mrs(struct rpcrdma_xprt *r_xprt); static void rpcrdma_destroy_mrs(struct rpcrdma_buffer *buf); static void rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb); struct workqueue_struct *rpcrdma_receive_wq __read_mostly; int rpcrdma_alloc_wq(void) { struct workqueue_struct *recv_wq; recv_wq = alloc_workqueue("xprtrdma_receive", WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_HIGHPRI, 0); if (!recv_wq) return -ENOMEM; rpcrdma_receive_wq = recv_wq; return 0; } void rpcrdma_destroy_wq(void) { struct workqueue_struct *wq; if (rpcrdma_receive_wq) { wq = rpcrdma_receive_wq; rpcrdma_receive_wq = NULL; destroy_workqueue(wq); } } static void rpcrdma_qp_async_error_upcall(struct ib_event *event, void *context) { struct rpcrdma_ep *ep = context; pr_err("rpcrdma: %s on device %s ep %p\n", ib_event_msg(event->event), event->device->name, context); if (ep->rep_connected == 1) { ep->rep_connected = -EIO; rpcrdma_conn_func(ep); wake_up_all(&ep->rep_connect_wait); } } /** * rpcrdma_wc_send - Invoked by RDMA provider for each polled Send WC * @cq: completion queue (ignored) * @wc: completed WR * */ static void rpcrdma_wc_send(struct ib_cq *cq, struct ib_wc *wc) { struct ib_cqe *cqe = wc->wr_cqe; struct rpcrdma_sendctx *sc = container_of(cqe, struct rpcrdma_sendctx, sc_cqe); /* WARNING: Only wr_cqe and status are reliable at this point */ if (wc->status != IB_WC_SUCCESS && wc->status != IB_WC_WR_FLUSH_ERR) pr_err("rpcrdma: Send: %s (%u/0x%x)\n", ib_wc_status_msg(wc->status), wc->status, wc->vendor_err); rpcrdma_sendctx_put_locked(sc); } /** * rpcrdma_wc_receive - Invoked by RDMA provider for each polled Receive WC * @cq: completion queue (ignored) * @wc: completed WR * */ static void rpcrdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc) { 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) goto out_fail; /* status == SUCCESS means all fields in wc are trustworthy */ dprintk("RPC: %s: rep %p opcode 'recv', length %u: success\n", __func__, rep, wc->byte_len); rpcrdma_set_xdrlen(&rep->rr_hdrbuf, wc->byte_len); rep->rr_wc_flags = wc->wc_flags; rep->rr_inv_rkey = wc->ex.invalidate_rkey; ib_dma_sync_single_for_cpu(rdmab_device(rep->rr_rdmabuf), rdmab_addr(rep->rr_rdmabuf), wc->byte_len, DMA_FROM_DEVICE); out_schedule: rpcrdma_reply_handler(rep); return; out_fail: if (wc->status != IB_WC_WR_FLUSH_ERR) pr_err("rpcrdma: Recv: %s (%u/0x%x)\n", ib_wc_status_msg(wc->status), wc->status, wc->vendor_err); rpcrdma_set_xdrlen(&rep->rr_hdrbuf, 0); goto out_schedule; } static void rpcrdma_update_connect_private(struct rpcrdma_xprt *r_xprt, struct rdma_conn_param *param) { struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data; const struct rpcrdma_connect_private *pmsg = param->private_data; unsigned int rsize, wsize; /* Default settings for RPC-over-RDMA Version One */ r_xprt->rx_ia.ri_reminv_expected = false; r_xprt->rx_ia.ri_implicit_roundup = xprt_rdma_pad_optimize; rsize = RPCRDMA_V1_DEF_INLINE_SIZE; wsize = RPCRDMA_V1_DEF_INLINE_SIZE; if (pmsg && pmsg->cp_magic == rpcrdma_cmp_magic && pmsg->cp_version == RPCRDMA_CMP_VERSION) { r_xprt->rx_ia.ri_reminv_expected = true; r_xprt->rx_ia.ri_implicit_roundup = true; rsize = rpcrdma_decode_buffer_size(pmsg->cp_send_size); wsize = rpcrdma_decode_buffer_size(pmsg->cp_recv_size); } if (rsize < cdata->inline_rsize) cdata->inline_rsize = rsize; if (wsize < cdata->inline_wsize) cdata->inline_wsize = wsize; dprintk("RPC: %s: max send %u, max recv %u\n", __func__, cdata->inline_wsize, cdata->inline_rsize); rpcrdma_set_max_header_sizes(r_xprt); } static int rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event) { struct rpcrdma_xprt *xprt = id->context; struct rpcrdma_ia *ia = &xprt->rx_ia; struct rpcrdma_ep *ep = &xprt->rx_ep; #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) struct sockaddr *sap = (struct sockaddr *)&ep->rep_remote_addr; #endif int connstate = 0; switch (event->event) { case RDMA_CM_EVENT_ADDR_RESOLVED: case RDMA_CM_EVENT_ROUTE_RESOLVED: ia->ri_async_rc = 0; complete(&ia->ri_done); break; case RDMA_CM_EVENT_ADDR_ERROR: ia->ri_async_rc = -EHOSTUNREACH; dprintk("RPC: %s: CM address resolution error, ep 0x%p\n", __func__, ep); complete(&ia->ri_done); break; case RDMA_CM_EVENT_ROUTE_ERROR: ia->ri_async_rc = -ENETUNREACH; dprintk("RPC: %s: CM route resolution error, ep 0x%p\n", __func__, ep); complete(&ia->ri_done); break; case RDMA_CM_EVENT_DEVICE_REMOVAL: #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) pr_info("rpcrdma: removing device %s for %pIS:%u\n", ia->ri_device->name, sap, rpc_get_port(sap)); #endif set_bit(RPCRDMA_IAF_REMOVING, &ia->ri_flags); ep->rep_connected = -ENODEV; xprt_force_disconnect(&xprt->rx_xprt); wait_for_completion(&ia->ri_remove_done); ia->ri_id = NULL; ia->ri_pd = NULL; ia->ri_device = NULL; /* Return 1 to ensure the core destroys the id. */ return 1; case RDMA_CM_EVENT_ESTABLISHED: connstate = 1; rpcrdma_update_connect_private(xprt, &event->param.conn); goto connected; case RDMA_CM_EVENT_CONNECT_ERROR: connstate = -ENOTCONN; goto connected; case RDMA_CM_EVENT_UNREACHABLE: connstate = -ENETDOWN; goto connected; case RDMA_CM_EVENT_REJECTED: dprintk("rpcrdma: connection to %pIS:%u rejected: %s\n", sap, rpc_get_port(sap), rdma_reject_msg(id, event->status)); connstate = -ECONNREFUSED; if (event->status == IB_CM_REJ_STALE_CONN) connstate = -EAGAIN; goto connected; case RDMA_CM_EVENT_DISCONNECTED: connstate = -ECONNABORTED; connected: xprt->rx_buf.rb_credits = 1; ep->rep_connected = connstate; rpcrdma_conn_func(ep); wake_up_all(&ep->rep_connect_wait); /*FALLTHROUGH*/ default: dprintk("RPC: %s: %pIS:%u on %s/%s (ep 0x%p): %s\n", __func__, sap, rpc_get_port(sap), ia->ri_device->name, ia->ri_ops->ro_displayname, ep, rdma_event_msg(event->event)); break; } return 0; } static struct rdma_cm_id * rpcrdma_create_id(struct rpcrdma_xprt *xprt, struct rpcrdma_ia *ia, struct sockaddr *addr) { unsigned long wtimeout = msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1; struct rdma_cm_id *id; int rc; init_completion(&ia->ri_done); init_completion(&ia->ri_remove_done); id = rdma_create_id(&init_net, rpcrdma_conn_upcall, xprt, RDMA_PS_TCP, IB_QPT_RC); if (IS_ERR(id)) { rc = PTR_ERR(id); dprintk("RPC: %s: rdma_create_id() failed %i\n", __func__, rc); return id; } ia->ri_async_rc = -ETIMEDOUT; rc = rdma_resolve_addr(id, NULL, addr, RDMA_RESOLVE_TIMEOUT); if (rc) { dprintk("RPC: %s: rdma_resolve_addr() failed %i\n", __func__, rc); goto out; } rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout); if (rc < 0) { dprintk("RPC: %s: wait() exited: %i\n", __func__, rc); goto out; } rc = ia->ri_async_rc; if (rc) goto out; ia->ri_async_rc = -ETIMEDOUT; rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT); if (rc) { dprintk("RPC: %s: rdma_resolve_route() failed %i\n", __func__, rc); goto out; } rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout); if (rc < 0) { dprintk("RPC: %s: wait() exited: %i\n", __func__, rc); goto out; } rc = ia->ri_async_rc; if (rc) goto out; return id; out: rdma_destroy_id(id); return ERR_PTR(rc); } /* * Exported functions. */ /** * rpcrdma_ia_open - Open and initialize an Interface Adapter. * @xprt: controlling transport * @addr: IP address of remote peer * * Returns 0 on success, negative errno if an appropriate * Interface Adapter could not be found and opened. */ int rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr) { struct rpcrdma_ia *ia = &xprt->rx_ia; int rc; ia->ri_id = rpcrdma_create_id(xprt, ia, addr); if (IS_ERR(ia->ri_id)) { rc = PTR_ERR(ia->ri_id); goto out_err; } ia->ri_device = ia->ri_id->device; ia->ri_pd = ib_alloc_pd(ia->ri_device, 0); if (IS_ERR(ia->ri_pd)) { rc = PTR_ERR(ia->ri_pd); pr_err("rpcrdma: ib_alloc_pd() returned %d\n", rc); goto out_err; } switch (xprt_rdma_memreg_strategy) { case RPCRDMA_FRMR: if (frwr_is_supported(ia)) { ia->ri_ops = &rpcrdma_frwr_memreg_ops; break; } /*FALLTHROUGH*/ case RPCRDMA_MTHCAFMR: if (fmr_is_supported(ia)) { ia->ri_ops = &rpcrdma_fmr_memreg_ops; break; } /*FALLTHROUGH*/ default: pr_err("rpcrdma: Device %s does not support memreg mode %d\n", ia->ri_device->name, xprt_rdma_memreg_strategy); rc = -EINVAL; goto out_err; } return 0; out_err: rpcrdma_ia_close(ia); return rc; } /** * rpcrdma_ia_remove - Handle device driver unload * @ia: interface adapter being removed * * Divest transport H/W resources associated with this adapter, * but allow it to be restored later. */ void rpcrdma_ia_remove(struct rpcrdma_ia *ia) { struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt, rx_ia); struct rpcrdma_ep *ep = &r_xprt->rx_ep; struct rpcrdma_buffer *buf = &r_xprt->rx_buf; struct rpcrdma_req *req; struct rpcrdma_rep *rep; cancel_delayed_work_sync(&buf->rb_refresh_worker); /* This is similar to rpcrdma_ep_destroy, but: * - Don't cancel the connect worker. * - Don't call rpcrdma_ep_disconnect, which waits * for another conn upcall, which will deadlock. * - rdma_disconnect is unneeded, the underlying * connection is already gone. */ if (ia->ri_id->qp) { ib_drain_qp(ia->ri_id->qp); rdma_destroy_qp(ia->ri_id); ia->ri_id->qp = NULL; } ib_free_cq(ep->rep_attr.recv_cq); ib_free_cq(ep->rep_attr.send_cq); /* The ULP is responsible for ensuring all DMA * mappings and MRs are gone. */ list_for_each_entry(rep, &buf->rb_recv_bufs, rr_list) rpcrdma_dma_unmap_regbuf(rep->rr_rdmabuf); list_for_each_entry(req, &buf->rb_allreqs, rl_all) { rpcrdma_dma_unmap_regbuf(req->rl_rdmabuf); rpcrdma_dma_unmap_regbuf(req->rl_sendbuf); rpcrdma_dma_unmap_regbuf(req->rl_recvbuf); } rpcrdma_destroy_mrs(buf); /* Allow waiters to continue */ complete(&ia->ri_remove_done); } /** * rpcrdma_ia_close - Clean up/close an IA. * @ia: interface adapter to close * */ void rpcrdma_ia_close(struct rpcrdma_ia *ia) { dprintk("RPC: %s: entering\n", __func__); if (ia->ri_id != NULL && !IS_ERR(ia->ri_id)) { if (ia->ri_id->qp) rdma_destroy_qp(ia->ri_id); rdma_destroy_id(ia->ri_id); } ia->ri_id = NULL; ia->ri_device = NULL; /* If the pd is still busy, xprtrdma missed freeing a resource */ if (ia->ri_pd && !IS_ERR(ia->ri_pd)) ib_dealloc_pd(ia->ri_pd); ia->ri_pd = NULL; } /* * Create unconnected endpoint. */ int rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, struct rpcrdma_create_data_internal *cdata) { struct rpcrdma_connect_private *pmsg = &ep->rep_cm_private; unsigned int max_qp_wr, max_sge; struct ib_cq *sendcq, *recvcq; int rc; max_sge = min_t(unsigned int, ia->ri_device->attrs.max_sge, RPCRDMA_MAX_SEND_SGES); if (max_sge < RPCRDMA_MIN_SEND_SGES) { pr_warn("rpcrdma: HCA provides only %d send SGEs\n", max_sge); return -ENOMEM; } ia->ri_max_send_sges = max_sge - RPCRDMA_MIN_SEND_SGES; if (ia->ri_device->attrs.max_qp_wr <= RPCRDMA_BACKWARD_WRS) { dprintk("RPC: %s: insufficient wqe's available\n", __func__); return -ENOMEM; } max_qp_wr = ia->ri_device->attrs.max_qp_wr - RPCRDMA_BACKWARD_WRS - 1; /* check provider's send/recv wr limits */ if (cdata->max_requests > max_qp_wr) cdata->max_requests = max_qp_wr; ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall; ep->rep_attr.qp_context = ep; ep->rep_attr.srq = NULL; ep->rep_attr.cap.max_send_wr = cdata->max_requests; ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS; ep->rep_attr.cap.max_send_wr += 1; /* drain cqe */ rc = ia->ri_ops->ro_open(ia, ep, cdata); if (rc) return rc; ep->rep_attr.cap.max_recv_wr = cdata->max_requests; ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS; ep->rep_attr.cap.max_recv_wr += 1; /* drain cqe */ ep->rep_attr.cap.max_send_sge = max_sge; ep->rep_attr.cap.max_recv_sge = 1; ep->rep_attr.cap.max_inline_data = 0; ep->rep_attr.sq_sig_type = IB_SIGNAL_REQ_WR; ep->rep_attr.qp_type = IB_QPT_RC; ep->rep_attr.port_num = ~0; dprintk("RPC: %s: requested max: dtos: send %d recv %d; " "iovs: send %d recv %d\n", __func__, ep->rep_attr.cap.max_send_wr, ep->rep_attr.cap.max_recv_wr, ep->rep_attr.cap.max_send_sge, ep->rep_attr.cap.max_recv_sge); /* set trigger for requesting send completion */ ep->rep_send_batch = min_t(unsigned int, RPCRDMA_MAX_SEND_BATCH, cdata->max_requests >> 2); ep->rep_send_count = ep->rep_send_batch; ep->rep_cqinit = ep->rep_attr.cap.max_send_wr/2 - 1; if (ep->rep_cqinit <= 2) ep->rep_cqinit = 0; /* always signal? */ rpcrdma_init_cqcount(ep, 0); init_waitqueue_head(&ep->rep_connect_wait); INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker); sendcq = ib_alloc_cq(ia->ri_device, NULL, ep->rep_attr.cap.max_send_wr + 1, 0, IB_POLL_SOFTIRQ); if (IS_ERR(sendcq)) { rc = PTR_ERR(sendcq); dprintk("RPC: %s: failed to create send CQ: %i\n", __func__, rc); goto out1; } recvcq = ib_alloc_cq(ia->ri_device, NULL, ep->rep_attr.cap.max_recv_wr + 1, 0, IB_POLL_WORKQUEUE); if (IS_ERR(recvcq)) { rc = PTR_ERR(recvcq); dprintk("RPC: %s: failed to create recv CQ: %i\n", __func__, rc); goto out2; } ep->rep_attr.send_cq = sendcq; ep->rep_attr.recv_cq = recvcq; /* Initialize cma parameters */ memset(&ep->rep_remote_cma, 0, sizeof(ep->rep_remote_cma)); /* Prepare RDMA-CM private message */ pmsg->cp_magic = rpcrdma_cmp_magic; pmsg->cp_version = RPCRDMA_CMP_VERSION; pmsg->cp_flags |= ia->ri_ops->ro_send_w_inv_ok; pmsg->cp_send_size = rpcrdma_encode_buffer_size(cdata->inline_wsize); pmsg->cp_recv_size = rpcrdma_encode_buffer_size(cdata->inline_rsize); ep->rep_remote_cma.private_data = pmsg; ep->rep_remote_cma.private_data_len = sizeof(*pmsg); /* Client offers RDMA Read but does not initiate */ ep->rep_remote_cma.initiator_depth = 0; if (ia->ri_device->attrs.max_qp_rd_atom > 32) /* arbitrary but <= 255 */ ep->rep_remote_cma.responder_resources = 32; else ep->rep_remote_cma.responder_resources = ia->ri_device->attrs.max_qp_rd_atom; /* Limit transport retries so client can detect server * GID changes quickly. RPC layer handles re-establishing * transport connection and retransmission. */ ep->rep_remote_cma.retry_count = 6; /* RPC-over-RDMA handles its own flow control. In addition, * make all RNR NAKs visible so we know that RPC-over-RDMA * flow control is working correctly (no NAKs should be seen). */ ep->rep_remote_cma.flow_control = 0; ep->rep_remote_cma.rnr_retry_count = 0; return 0; out2: ib_free_cq(sendcq); out1: return rc; } /* * rpcrdma_ep_destroy * * Disconnect and destroy endpoint. After this, the only * valid operations on the ep are to free it (if dynamically * allocated) or re-create it. */ void rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) { dprintk("RPC: %s: entering, connected is %d\n", __func__, ep->rep_connected); cancel_delayed_work_sync(&ep->rep_connect_worker); if (ia->ri_id->qp) { rpcrdma_ep_disconnect(ep, ia); rdma_destroy_qp(ia->ri_id); ia->ri_id->qp = NULL; } ib_free_cq(ep->rep_attr.recv_cq); ib_free_cq(ep->rep_attr.send_cq); } /* Re-establish a connection after a device removal event. * Unlike a normal reconnection, a fresh PD and a new set * of MRs and buffers is needed. */ static int rpcrdma_ep_recreate_xprt(struct rpcrdma_xprt *r_xprt, struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) { struct sockaddr *sap = (struct sockaddr *)&r_xprt->rx_data.addr; int rc, err; pr_info("%s: r_xprt = %p\n", __func__, r_xprt); rc = -EHOSTUNREACH; if (rpcrdma_ia_open(r_xprt, sap)) goto out1; rc = -ENOMEM; err = rpcrdma_ep_create(ep, ia, &r_xprt->rx_data); if (err) { pr_err("rpcrdma: rpcrdma_ep_create returned %d\n", err); goto out2; } rc = -ENETUNREACH; err = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr); if (err) { pr_err("rpcrdma: rdma_create_qp returned %d\n", err); goto out3; } rpcrdma_create_mrs(r_xprt); return 0; out3: rpcrdma_ep_destroy(ep, ia); out2: rpcrdma_ia_close(ia); out1: return rc; } static int rpcrdma_ep_reconnect(struct rpcrdma_xprt *r_xprt, struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) { struct sockaddr *sap = (struct sockaddr *)&r_xprt->rx_data.addr; struct rdma_cm_id *id, *old; int err, rc; dprintk("RPC: %s: reconnecting...\n", __func__); rpcrdma_ep_disconnect(ep, ia); rc = -EHOSTUNREACH; id = rpcrdma_create_id(r_xprt, ia, sap); if (IS_ERR(id)) goto out; /* As long as the new ID points to the same device as the * old ID, we can reuse the transport's existing PD and all * previously allocated MRs. Also, the same device means * the transport's previous DMA mappings are still valid. * * This is a sanity check only. There should be no way these * point to two different devices here. */ old = id; rc = -ENETUNREACH; if (ia->ri_device != id->device) { pr_err("rpcrdma: can't reconnect on different device!\n"); goto out_destroy; } err = rdma_create_qp(id, ia->ri_pd, &ep->rep_attr); if (err) { dprintk("RPC: %s: rdma_create_qp returned %d\n", __func__, err); goto out_destroy; } /* Atomically replace the transport's ID and QP. */ rc = 0; old = ia->ri_id; ia->ri_id = id; rdma_destroy_qp(old); out_destroy: rdma_destroy_id(old); out: return rc; } /* * Connect unconnected endpoint. */ int rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) { struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt, rx_ia); unsigned int extras; int rc; retry: switch (ep->rep_connected) { case 0: dprintk("RPC: %s: connecting...\n", __func__); rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr); if (rc) { dprintk("RPC: %s: rdma_create_qp failed %i\n", __func__, rc); rc = -ENETUNREACH; goto out_noupdate; } break; case -ENODEV: rc = rpcrdma_ep_recreate_xprt(r_xprt, ep, ia); if (rc) goto out_noupdate; break; default: rc = rpcrdma_ep_reconnect(r_xprt, ep, ia); if (rc) goto out; } ep->rep_connected = 0; rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma); if (rc) { dprintk("RPC: %s: rdma_connect() failed with %i\n", __func__, rc); goto out; } wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 0); if (ep->rep_connected <= 0) { if (ep->rep_connected == -EAGAIN) goto retry; rc = ep->rep_connected; goto out; } dprintk("RPC: %s: connected\n", __func__); extras = r_xprt->rx_buf.rb_bc_srv_max_requests; if (extras) rpcrdma_ep_post_extra_recv(r_xprt, extras); out: if (rc) ep->rep_connected = rc; out_noupdate: return rc; } /* * rpcrdma_ep_disconnect * * This is separate from destroy to facilitate the ability * to reconnect without recreating the endpoint. * * This call is not reentrant, and must not be made in parallel * on the same endpoint. */ void rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) { int rc; rc = rdma_disconnect(ia->ri_id); if (!rc) { /* returns without wait if not connected */ wait_event_interruptible(ep->rep_connect_wait, ep->rep_connected != 1); dprintk("RPC: %s: after wait, %sconnected\n", __func__, (ep->rep_connected == 1) ? "still " : "dis"); } else { dprintk("RPC: %s: rdma_disconnect %i\n", __func__, rc); ep->rep_connected = rc; } ib_drain_qp(ia->ri_id->qp); } /* Fixed-size circular FIFO queue. This implementation is wait-free and * lock-free. * * Consumer is the code path that posts Sends. This path dequeues a * sendctx for use by a Send operation. Multiple consumer threads * are serialized by the RPC transport lock, which allows only one * ->send_request call at a time. * * Producer is the code path that handles Send completions. This path * enqueues a sendctx that has been completed. Multiple producer * threads are serialized by the ib_poll_cq() function. */ /* rpcrdma_sendctxs_destroy() assumes caller has already quiesced * queue activity, and ib_drain_qp has flushed all remaining Send * requests. */ static void rpcrdma_sendctxs_destroy(struct rpcrdma_buffer *buf) { unsigned long i; for (i = 0; i <= buf->rb_sc_last; i++) kfree(buf->rb_sc_ctxs[i]); kfree(buf->rb_sc_ctxs); } static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia) { struct rpcrdma_sendctx *sc; sc = kzalloc(sizeof(*sc) + ia->ri_max_send_sges * sizeof(struct ib_sge), GFP_KERNEL); if (!sc) return NULL; sc->sc_wr.wr_cqe = &sc->sc_cqe; sc->sc_wr.sg_list = sc->sc_sges; sc->sc_wr.opcode = IB_WR_SEND; sc->sc_cqe.done = rpcrdma_wc_send; return sc; } static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_buffer *buf = &r_xprt->rx_buf; struct rpcrdma_sendctx *sc; unsigned long i; /* Maximum number of concurrent outstanding Send WRs. Capping * the circular queue size stops Send Queue overflow by causing * the ->send_request call to fail temporarily before too many * Sends are posted. */ i = buf->rb_max_requests + RPCRDMA_MAX_BC_REQUESTS; dprintk("RPC: %s: allocating %lu send_ctxs\n", __func__, i); buf->rb_sc_ctxs = kcalloc(i, sizeof(sc), GFP_KERNEL); if (!buf->rb_sc_ctxs) return -ENOMEM; buf->rb_sc_last = i - 1; for (i = 0; i <= buf->rb_sc_last; i++) { sc = rpcrdma_sendctx_create(&r_xprt->rx_ia); if (!sc) goto out_destroy; sc->sc_xprt = r_xprt; buf->rb_sc_ctxs[i] = sc; } return 0; out_destroy: rpcrdma_sendctxs_destroy(buf); return -ENOMEM; } /* The sendctx queue is not guaranteed to have a size that is a * power of two, thus the helpers in circ_buf.h cannot be used. * The other option is to use modulus (%), which can be expensive. */ static unsigned long rpcrdma_sendctx_next(struct rpcrdma_buffer *buf, unsigned long item) { return likely(item < buf->rb_sc_last) ? item + 1 : 0; } /** * rpcrdma_sendctx_get_locked - Acquire a send context * @buf: transport buffers from which to acquire an unused context * * Returns pointer to a free send completion context; or NULL if * the queue is empty. * * Usage: Called to acquire an SGE array before preparing a Send WR. * * The caller serializes calls to this function (per rpcrdma_buffer), * and provides an effective memory barrier that flushes the new value * of rb_sc_head. */ struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_buffer *buf) { struct rpcrdma_xprt *r_xprt; struct rpcrdma_sendctx *sc; unsigned long next_head; next_head = rpcrdma_sendctx_next(buf, buf->rb_sc_head); if (next_head == READ_ONCE(buf->rb_sc_tail)) goto out_emptyq; /* ORDER: item must be accessed _before_ head is updated */ sc = buf->rb_sc_ctxs[next_head]; /* Releasing the lock in the caller acts as a memory * barrier that flushes rb_sc_head. */ buf->rb_sc_head = next_head; return sc; out_emptyq: /* The queue is "empty" if there have not been enough Send * completions recently. This is a sign the Send Queue is * backing up. Cause the caller to pause and try again. */ dprintk("RPC: %s: empty sendctx queue\n", __func__); r_xprt = container_of(buf, struct rpcrdma_xprt, rx_buf); r_xprt->rx_stats.empty_sendctx_q++; return NULL; } /** * rpcrdma_sendctx_put_locked - Release a send context * @sc: send context to release * * Usage: Called from Send completion to return a sendctxt * to the queue. * * The caller serializes calls to this function (per rpcrdma_buffer). */ void rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc) { struct rpcrdma_buffer *buf = &sc->sc_xprt->rx_buf; unsigned long next_tail; /* Unmap SGEs of previously completed by unsignaled * Sends by walking up the queue until @sc is found. */ next_tail = buf->rb_sc_tail; do { next_tail = rpcrdma_sendctx_next(buf, next_tail); /* ORDER: item must be accessed _before_ tail is updated */ rpcrdma_unmap_sendctx(buf->rb_sc_ctxs[next_tail]); } while (buf->rb_sc_ctxs[next_tail] != sc); /* Paired with READ_ONCE */ smp_store_release(&buf->rb_sc_tail, next_tail); } static void rpcrdma_mr_recovery_worker(struct work_struct *work) { struct rpcrdma_buffer *buf = container_of(work, struct rpcrdma_buffer, rb_recovery_worker.work); struct rpcrdma_mw *mw; spin_lock(&buf->rb_recovery_lock); while (!list_empty(&buf->rb_stale_mrs)) { mw = rpcrdma_pop_mw(&buf->rb_stale_mrs); spin_unlock(&buf->rb_recovery_lock); dprintk("RPC: %s: recovering MR %p\n", __func__, mw); mw->mw_xprt->rx_ia.ri_ops->ro_recover_mr(mw); spin_lock(&buf->rb_recovery_lock); } spin_unlock(&buf->rb_recovery_lock); } void rpcrdma_defer_mr_recovery(struct rpcrdma_mw *mw) { struct rpcrdma_xprt *r_xprt = mw->mw_xprt; struct rpcrdma_buffer *buf = &r_xprt->rx_buf; spin_lock(&buf->rb_recovery_lock); rpcrdma_push_mw(mw, &buf->rb_stale_mrs); spin_unlock(&buf->rb_recovery_lock); schedule_delayed_work(&buf->rb_recovery_worker, 0); } static void rpcrdma_create_mrs(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_buffer *buf = &r_xprt->rx_buf; struct rpcrdma_ia *ia = &r_xprt->rx_ia; unsigned int count; LIST_HEAD(free); LIST_HEAD(all); for (count = 0; count < 32; count++) { struct rpcrdma_mw *mw; int rc; mw = kzalloc(sizeof(*mw), GFP_KERNEL); if (!mw) break; rc = ia->ri_ops->ro_init_mr(ia, mw); if (rc) { kfree(mw); break; } mw->mw_xprt = r_xprt; list_add(&mw->mw_list, &free); list_add(&mw->mw_all, &all); } spin_lock(&buf->rb_mwlock); list_splice(&free, &buf->rb_mws); list_splice(&all, &buf->rb_all); r_xprt->rx_stats.mrs_allocated += count; spin_unlock(&buf->rb_mwlock); dprintk("RPC: %s: created %u MRs\n", __func__, count); } static void rpcrdma_mr_refresh_worker(struct work_struct *work) { struct rpcrdma_buffer *buf = container_of(work, struct rpcrdma_buffer, rb_refresh_worker.work); struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt, rx_buf); rpcrdma_create_mrs(r_xprt); } struct rpcrdma_req * rpcrdma_create_req(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_buffer *buffer = &r_xprt->rx_buf; struct rpcrdma_req *req; req = kzalloc(sizeof(*req), GFP_KERNEL); if (req == NULL) return ERR_PTR(-ENOMEM); spin_lock(&buffer->rb_reqslock); list_add(&req->rl_all, &buffer->rb_allreqs); spin_unlock(&buffer->rb_reqslock); req->rl_buffer = &r_xprt->rx_buf; INIT_LIST_HEAD(&req->rl_registered); return req; } struct rpcrdma_rep * rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data; struct rpcrdma_rep *rep; int rc; rc = -ENOMEM; rep = kzalloc(sizeof(*rep), GFP_KERNEL); if (rep == NULL) goto out; rep->rr_rdmabuf = rpcrdma_alloc_regbuf(cdata->inline_rsize, DMA_FROM_DEVICE, GFP_KERNEL); if (IS_ERR(rep->rr_rdmabuf)) { rc = PTR_ERR(rep->rr_rdmabuf); goto out_free; } xdr_buf_init(&rep->rr_hdrbuf, rep->rr_rdmabuf->rg_base, rdmab_length(rep->rr_rdmabuf)); rep->rr_cqe.done = rpcrdma_wc_receive; rep->rr_rxprt = r_xprt; INIT_WORK(&rep->rr_work, rpcrdma_deferred_completion); rep->rr_recv_wr.next = NULL; rep->rr_recv_wr.wr_cqe = &rep->rr_cqe; rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov; rep->rr_recv_wr.num_sge = 1; return rep; out_free: kfree(rep); out: return ERR_PTR(rc); } int rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_buffer *buf = &r_xprt->rx_buf; int i, rc; buf->rb_max_requests = r_xprt->rx_data.max_requests; buf->rb_bc_srv_max_requests = 0; spin_lock_init(&buf->rb_mwlock); spin_lock_init(&buf->rb_lock); spin_lock_init(&buf->rb_recovery_lock); INIT_LIST_HEAD(&buf->rb_mws); INIT_LIST_HEAD(&buf->rb_all); INIT_LIST_HEAD(&buf->rb_stale_mrs); INIT_DELAYED_WORK(&buf->rb_refresh_worker, rpcrdma_mr_refresh_worker); INIT_DELAYED_WORK(&buf->rb_recovery_worker, rpcrdma_mr_recovery_worker); rpcrdma_create_mrs(r_xprt); INIT_LIST_HEAD(&buf->rb_send_bufs); INIT_LIST_HEAD(&buf->rb_allreqs); spin_lock_init(&buf->rb_reqslock); for (i = 0; i < buf->rb_max_requests; i++) { struct rpcrdma_req *req; req = rpcrdma_create_req(r_xprt); if (IS_ERR(req)) { dprintk("RPC: %s: request buffer %d alloc" " failed\n", __func__, i); rc = PTR_ERR(req); goto out; } req->rl_backchannel = false; list_add(&req->rl_list, &buf->rb_send_bufs); } INIT_LIST_HEAD(&buf->rb_recv_bufs); for (i = 0; i < buf->rb_max_requests + RPCRDMA_MAX_BC_REQUESTS; i++) { struct rpcrdma_rep *rep; rep = rpcrdma_create_rep(r_xprt); if (IS_ERR(rep)) { dprintk("RPC: %s: reply buffer %d alloc failed\n", __func__, i); rc = PTR_ERR(rep); goto out; } list_add(&rep->rr_list, &buf->rb_recv_bufs); } rc = rpcrdma_sendctxs_create(r_xprt); if (rc) goto out; return 0; out: rpcrdma_buffer_destroy(buf); return rc; } static struct rpcrdma_req * rpcrdma_buffer_get_req_locked(struct rpcrdma_buffer *buf) { struct rpcrdma_req *req; req = list_first_entry(&buf->rb_send_bufs, struct rpcrdma_req, rl_list); list_del_init(&req->rl_list); return req; } static struct rpcrdma_rep * rpcrdma_buffer_get_rep_locked(struct rpcrdma_buffer *buf) { struct rpcrdma_rep *rep; rep = list_first_entry(&buf->rb_recv_bufs, struct rpcrdma_rep, rr_list); list_del(&rep->rr_list); return rep; } static void rpcrdma_destroy_rep(struct rpcrdma_rep *rep) { rpcrdma_free_regbuf(rep->rr_rdmabuf); kfree(rep); } void rpcrdma_destroy_req(struct rpcrdma_req *req) { rpcrdma_free_regbuf(req->rl_recvbuf); rpcrdma_free_regbuf(req->rl_sendbuf); rpcrdma_free_regbuf(req->rl_rdmabuf); kfree(req); } static void rpcrdma_destroy_mrs(struct rpcrdma_buffer *buf) { struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt, rx_buf); struct rpcrdma_ia *ia = rdmab_to_ia(buf); struct rpcrdma_mw *mw; unsigned int count; count = 0; spin_lock(&buf->rb_mwlock); while (!list_empty(&buf->rb_all)) { mw = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all); list_del(&mw->mw_all); spin_unlock(&buf->rb_mwlock); ia->ri_ops->ro_release_mr(mw); count++; spin_lock(&buf->rb_mwlock); } spin_unlock(&buf->rb_mwlock); r_xprt->rx_stats.mrs_allocated = 0; dprintk("RPC: %s: released %u MRs\n", __func__, count); } void rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf) { cancel_delayed_work_sync(&buf->rb_recovery_worker); cancel_delayed_work_sync(&buf->rb_refresh_worker); rpcrdma_sendctxs_destroy(buf); while (!list_empty(&buf->rb_recv_bufs)) { struct rpcrdma_rep *rep; rep = rpcrdma_buffer_get_rep_locked(buf); rpcrdma_destroy_rep(rep); } buf->rb_send_count = 0; spin_lock(&buf->rb_reqslock); while (!list_empty(&buf->rb_allreqs)) { struct rpcrdma_req *req; req = list_first_entry(&buf->rb_allreqs, struct rpcrdma_req, rl_all); list_del(&req->rl_all); spin_unlock(&buf->rb_reqslock); rpcrdma_destroy_req(req); spin_lock(&buf->rb_reqslock); } spin_unlock(&buf->rb_reqslock); buf->rb_recv_count = 0; rpcrdma_destroy_mrs(buf); } struct rpcrdma_mw * rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_buffer *buf = &r_xprt->rx_buf; struct rpcrdma_mw *mw = NULL; spin_lock(&buf->rb_mwlock); if (!list_empty(&buf->rb_mws)) mw = rpcrdma_pop_mw(&buf->rb_mws); spin_unlock(&buf->rb_mwlock); if (!mw) goto out_nomws; mw->mw_flags = 0; return mw; out_nomws: dprintk("RPC: %s: no MWs available\n", __func__); if (r_xprt->rx_ep.rep_connected != -ENODEV) schedule_delayed_work(&buf->rb_refresh_worker, 0); /* Allow the reply handler and refresh worker to run */ cond_resched(); return NULL; } void rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw) { struct rpcrdma_buffer *buf = &r_xprt->rx_buf; spin_lock(&buf->rb_mwlock); rpcrdma_push_mw(mw, &buf->rb_mws); spin_unlock(&buf->rb_mwlock); } static struct rpcrdma_rep * rpcrdma_buffer_get_rep(struct rpcrdma_buffer *buffers) { /* If an RPC previously completed without a reply (say, a * credential problem or a soft timeout occurs) then hold off * on supplying more Receive buffers until the number of new * pending RPCs catches up to the number of posted Receives. */ if (unlikely(buffers->rb_send_count < buffers->rb_recv_count)) return NULL; if (unlikely(list_empty(&buffers->rb_recv_bufs))) return NULL; buffers->rb_recv_count++; return rpcrdma_buffer_get_rep_locked(buffers); } /* * Get a set of request/reply buffers. * * Reply buffer (if available) is attached to send buffer upon return. */ struct rpcrdma_req * rpcrdma_buffer_get(struct rpcrdma_buffer *buffers) { struct rpcrdma_req *req; spin_lock(&buffers->rb_lock); if (list_empty(&buffers->rb_send_bufs)) goto out_reqbuf; buffers->rb_send_count++; req = rpcrdma_buffer_get_req_locked(buffers); req->rl_reply = rpcrdma_buffer_get_rep(buffers); spin_unlock(&buffers->rb_lock); return req; out_reqbuf: spin_unlock(&buffers->rb_lock); pr_warn("RPC: %s: out of request buffers\n", __func__); return NULL; } /* * Put request/reply buffers back into pool. * Pre-decrement counter/array index. */ void rpcrdma_buffer_put(struct rpcrdma_req *req) { struct rpcrdma_buffer *buffers = req->rl_buffer; struct rpcrdma_rep *rep = req->rl_reply; req->rl_reply = NULL; spin_lock(&buffers->rb_lock); buffers->rb_send_count--; list_add_tail(&req->rl_list, &buffers->rb_send_bufs); if (rep) { buffers->rb_recv_count--; list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs); } spin_unlock(&buffers->rb_lock); } /* * Recover reply buffers from pool. * This happens when recovering from disconnect. */ void rpcrdma_recv_buffer_get(struct rpcrdma_req *req) { struct rpcrdma_buffer *buffers = req->rl_buffer; spin_lock(&buffers->rb_lock); req->rl_reply = rpcrdma_buffer_get_rep(buffers); spin_unlock(&buffers->rb_lock); } /* * Put reply buffers back into pool when not attached to * request. This happens in error conditions. */ void rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep) { struct rpcrdma_buffer *buffers = &rep->rr_rxprt->rx_buf; spin_lock(&buffers->rb_lock); buffers->rb_recv_count--; list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs); spin_unlock(&buffers->rb_lock); } /** * rpcrdma_alloc_regbuf - allocate and DMA-map memory for SEND/RECV buffers * @size: size of buffer to be allocated, in bytes * @direction: direction of data movement * @flags: GFP flags * * Returns an ERR_PTR, or a pointer to a regbuf, a buffer that * can be persistently DMA-mapped for I/O. * * xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for * receiving the payload of RDMA RECV operations. During Long Calls * or Replies they may be registered externally via ro_map. */ struct rpcrdma_regbuf * rpcrdma_alloc_regbuf(size_t size, enum dma_data_direction direction, gfp_t flags) { struct rpcrdma_regbuf *rb; rb = kmalloc(sizeof(*rb) + size, flags); if (rb == NULL) return ERR_PTR(-ENOMEM); rb->rg_device = NULL; rb->rg_direction = direction; rb->rg_iov.length = size; return rb; } /** * __rpcrdma_map_regbuf - DMA-map a regbuf * @ia: controlling rpcrdma_ia * @rb: regbuf to be mapped */ bool __rpcrdma_dma_map_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb) { struct ib_device *device = ia->ri_device; if (rb->rg_direction == DMA_NONE) return false; rb->rg_iov.addr = ib_dma_map_single(device, (void *)rb->rg_base, rdmab_length(rb), rb->rg_direction); if (ib_dma_mapping_error(device, rdmab_addr(rb))) return false; rb->rg_device = device; rb->rg_iov.lkey = ia->ri_pd->local_dma_lkey; return true; } static void rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb) { if (!rpcrdma_regbuf_is_mapped(rb)) return; ib_dma_unmap_single(rb->rg_device, rdmab_addr(rb), rdmab_length(rb), rb->rg_direction); rb->rg_device = NULL; } /** * rpcrdma_free_regbuf - deregister and free registered buffer * @rb: regbuf to be deregistered and freed */ void rpcrdma_free_regbuf(struct rpcrdma_regbuf *rb) { if (!rb) return; rpcrdma_dma_unmap_regbuf(rb); kfree(rb); } /* * Prepost any receive buffer, then post send. * * Receive buffer is donated to hardware, reclaimed upon recv completion. */ int rpcrdma_ep_post(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep, struct rpcrdma_req *req) { struct ib_send_wr *send_wr = &req->rl_sendctx->sc_wr; struct ib_send_wr *send_wr_fail; int rc; if (req->rl_reply) { rc = rpcrdma_ep_post_recv(ia, req->rl_reply); if (rc) return rc; req->rl_reply = NULL; } dprintk("RPC: %s: posting %d s/g entries\n", __func__, send_wr->num_sge); if (!ep->rep_send_count) { send_wr->send_flags |= IB_SEND_SIGNALED; ep->rep_send_count = ep->rep_send_batch; } else { send_wr->send_flags &= ~IB_SEND_SIGNALED; --ep->rep_send_count; } rc = ib_post_send(ia->ri_id->qp, send_wr, &send_wr_fail); if (rc) goto out_postsend_err; return 0; out_postsend_err: pr_err("rpcrdma: RDMA Send ib_post_send returned %i\n", rc); return -ENOTCONN; } int rpcrdma_ep_post_recv(struct rpcrdma_ia *ia, struct rpcrdma_rep *rep) { struct ib_recv_wr *recv_wr_fail; int rc; if (!rpcrdma_dma_map_regbuf(ia, rep->rr_rdmabuf)) goto out_map; rc = ib_post_recv(ia->ri_id->qp, &rep->rr_recv_wr, &recv_wr_fail); if (rc) goto out_postrecv; return 0; out_map: pr_err("rpcrdma: failed to DMA map the Receive buffer\n"); return -EIO; out_postrecv: pr_err("rpcrdma: ib_post_recv returned %i\n", rc); return -ENOTCONN; } /** * rpcrdma_ep_post_extra_recv - Post buffers for incoming backchannel requests * @r_xprt: transport associated with these backchannel resources * @min_reqs: minimum number of incoming requests expected * * Returns zero if all requested buffers were posted, or a negative errno. */ int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *r_xprt, unsigned int count) { struct rpcrdma_buffer *buffers = &r_xprt->rx_buf; struct rpcrdma_ia *ia = &r_xprt->rx_ia; struct rpcrdma_rep *rep; int rc; while (count--) { spin_lock(&buffers->rb_lock); if (list_empty(&buffers->rb_recv_bufs)) goto out_reqbuf; rep = rpcrdma_buffer_get_rep_locked(buffers); spin_unlock(&buffers->rb_lock); rc = rpcrdma_ep_post_recv(ia, rep); if (rc) goto out_rc; } return 0; out_reqbuf: spin_unlock(&buffers->rb_lock); pr_warn("%s: no extra receive buffers\n", __func__); return -ENOMEM; out_rc: rpcrdma_recv_buffer_put(rep); return rc; }