X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=net%2Fsunrpc%2Fxprtrdma%2Fverbs.c;h=eadd1655145a3bc5b81bdefb7015792fb3be566a;hb=e6604ecb70d4b1dbc0372c6518b51c25c4b135a1;hp=f63369bd01c54b9d7df2a15511c1fa066289a91f;hpb=9d74288ca79249af4b906215788b37d52263b58b;p=firefly-linux-kernel-4.4.55.git diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index f63369bd01c5..eadd1655145a 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -68,47 +68,33 @@ * internal functions */ -/* - * handle replies in tasklet context, using a single, global list - * rdma tasklet function -- just turn around and call the func - * for all replies on the list - */ - -static DEFINE_SPINLOCK(rpcrdma_tk_lock_g); -static LIST_HEAD(rpcrdma_tasklets_g); +static struct workqueue_struct *rpcrdma_receive_wq; -static void -rpcrdma_run_tasklet(unsigned long data) +int +rpcrdma_alloc_wq(void) { - struct rpcrdma_rep *rep; - unsigned long flags; - - data = data; - spin_lock_irqsave(&rpcrdma_tk_lock_g, flags); - while (!list_empty(&rpcrdma_tasklets_g)) { - rep = list_entry(rpcrdma_tasklets_g.next, - struct rpcrdma_rep, rr_list); - list_del(&rep->rr_list); - spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags); + struct workqueue_struct *recv_wq; - rpcrdma_reply_handler(rep); + recv_wq = alloc_workqueue("xprtrdma_receive", + WQ_MEM_RECLAIM | WQ_UNBOUND | WQ_HIGHPRI, + 0); + if (!recv_wq) + return -ENOMEM; - spin_lock_irqsave(&rpcrdma_tk_lock_g, flags); - } - spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags); + rpcrdma_receive_wq = recv_wq; + return 0; } -static DECLARE_TASKLET(rpcrdma_tasklet_g, rpcrdma_run_tasklet, 0UL); - -static void -rpcrdma_schedule_tasklet(struct list_head *sched_list) +void +rpcrdma_destroy_wq(void) { - unsigned long flags; + struct workqueue_struct *wq; - spin_lock_irqsave(&rpcrdma_tk_lock_g, flags); - list_splice_tail(sched_list, &rpcrdma_tasklets_g); - spin_unlock_irqrestore(&rpcrdma_tk_lock_g, flags); - tasklet_schedule(&rpcrdma_tasklet_g); + if (rpcrdma_receive_wq) { + wq = rpcrdma_receive_wq; + rpcrdma_receive_wq = NULL; + destroy_workqueue(wq); + } } static void @@ -158,63 +144,54 @@ rpcrdma_sendcq_process_wc(struct ib_wc *wc) } } -static int -rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) +/* The common case is a single send completion is waiting. By + * passing two WC entries to ib_poll_cq, a return code of 1 + * means there is exactly one WC waiting and no more. We don't + * have to invoke ib_poll_cq again to know that the CQ has been + * properly drained. + */ +static void +rpcrdma_sendcq_poll(struct ib_cq *cq) { - struct ib_wc *wcs; - int budget, count, rc; + struct ib_wc *pos, wcs[2]; + int count, rc; - budget = RPCRDMA_WC_BUDGET / RPCRDMA_POLLSIZE; do { - wcs = ep->rep_send_wcs; + pos = wcs; - rc = ib_poll_cq(cq, RPCRDMA_POLLSIZE, wcs); - if (rc <= 0) - return rc; + rc = ib_poll_cq(cq, ARRAY_SIZE(wcs), pos); + if (rc < 0) + break; count = rc; while (count-- > 0) - rpcrdma_sendcq_process_wc(wcs++); - } while (rc == RPCRDMA_POLLSIZE && --budget); - return 0; + rpcrdma_sendcq_process_wc(pos++); + } while (rc == ARRAY_SIZE(wcs)); + return; } -/* - * Handle send, fast_reg_mr, and local_inv completions. - * - * Send events are typically suppressed and thus do not result - * in an upcall. Occasionally one is signaled, however. This - * prevents the provider's completion queue from wrapping and - * losing a completion. +/* Handle provider send completion upcalls. */ static void rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context) { - struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context; - int rc; - - rc = rpcrdma_sendcq_poll(cq, ep); - if (rc) { - dprintk("RPC: %s: ib_poll_cq failed: %i\n", - __func__, rc); - return; - } + do { + rpcrdma_sendcq_poll(cq); + } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP | + IB_CQ_REPORT_MISSED_EVENTS) > 0); +} - rc = ib_req_notify_cq(cq, - IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); - if (rc == 0) - return; - if (rc < 0) { - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", - __func__, rc); - return; - } +static void +rpcrdma_receive_worker(struct work_struct *work) +{ + struct rpcrdma_rep *rep = + container_of(work, struct rpcrdma_rep, rr_work); - rpcrdma_sendcq_poll(cq, ep); + rpcrdma_reply_handler(rep); } static void -rpcrdma_recvcq_process_wc(struct ib_wc *wc, struct list_head *sched_list) +rpcrdma_recvcq_process_wc(struct ib_wc *wc) { struct rpcrdma_rep *rep = (struct rpcrdma_rep *)(unsigned long)wc->wr_id; @@ -237,91 +214,60 @@ rpcrdma_recvcq_process_wc(struct ib_wc *wc, struct list_head *sched_list) prefetch(rdmab_to_msg(rep->rr_rdmabuf)); out_schedule: - list_add_tail(&rep->rr_list, sched_list); + queue_work(rpcrdma_receive_wq, &rep->rr_work); return; + 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)); - rep->rr_len = ~0U; + rep->rr_len = RPCRDMA_BAD_LEN; goto out_schedule; } -static int -rpcrdma_recvcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) +/* 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 list_head sched_list; - struct ib_wc *wcs; - int budget, count, rc; + struct ib_wc *pos, wcs[4]; + int count, rc; - INIT_LIST_HEAD(&sched_list); - budget = RPCRDMA_WC_BUDGET / RPCRDMA_POLLSIZE; do { - wcs = ep->rep_recv_wcs; + pos = wcs; - rc = ib_poll_cq(cq, RPCRDMA_POLLSIZE, wcs); - if (rc <= 0) - goto out_schedule; + rc = ib_poll_cq(cq, ARRAY_SIZE(wcs), pos); + if (rc < 0) + break; count = rc; while (count-- > 0) - rpcrdma_recvcq_process_wc(wcs++, &sched_list); - } while (rc == RPCRDMA_POLLSIZE && --budget); - rc = 0; - -out_schedule: - rpcrdma_schedule_tasklet(&sched_list); - return rc; + rpcrdma_recvcq_process_wc(pos++); + } while (rc == ARRAY_SIZE(wcs)); } -/* - * Handle receive completions. - * - * It is reentrant but processes single events in order to maintain - * ordering of receives to keep server credits. - * - * It is the responsibility of the scheduled tasklet to return - * recv buffers to the pool. NOTE: this affects synchronization of - * connection shutdown. That is, the structures required for - * the completion of the reply handler must remain intact until - * all memory has been reclaimed. +/* Handle provider receive completion upcalls. */ static void rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context) { - struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context; - int rc; - - rc = rpcrdma_recvcq_poll(cq, ep); - if (rc) { - dprintk("RPC: %s: ib_poll_cq failed: %i\n", - __func__, rc); - return; - } - - rc = ib_req_notify_cq(cq, - IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); - if (rc == 0) - return; - if (rc < 0) { - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", - __func__, rc); - return; - } - - rpcrdma_recvcq_poll(cq, ep); + 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; - LIST_HEAD(sched_list); while (ib_poll_cq(ep->rep_attr.recv_cq, 1, &wc) > 0) - rpcrdma_recvcq_process_wc(&wc, &sched_list); - if (!list_empty(&sched_list)) - rpcrdma_schedule_tasklet(&sched_list); + rpcrdma_recvcq_process_wc(&wc); while (ib_poll_cq(ep->rep_attr.send_cq, 1, &wc) > 0) rpcrdma_sendcq_process_wc(&wc); } @@ -623,6 +569,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, struct ib_device_attr *devattr = &ia->ri_devattr; struct ib_cq *sendcq, *recvcq; struct ib_cq_init_attr cq_attr = {}; + unsigned int max_qp_wr; int rc, err; if (devattr->max_sge < RPCRDMA_MAX_IOVS) { @@ -631,18 +578,27 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, return -ENOMEM; } + if (devattr->max_qp_wr <= RPCRDMA_BACKWARD_WRS) { + dprintk("RPC: %s: insufficient wqe's available\n", + __func__); + return -ENOMEM; + } + max_qp_wr = devattr->max_qp_wr - RPCRDMA_BACKWARD_WRS; + /* check provider's send/recv wr limits */ - if (cdata->max_requests > devattr->max_qp_wr) - cdata->max_requests = devattr->max_qp_wr; + 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; 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_send_sge = RPCRDMA_MAX_IOVS; ep->rep_attr.cap.max_recv_sge = 1; ep->rep_attr.cap.max_inline_data = 0; @@ -670,7 +626,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, cq_attr.cqe = ep->rep_attr.cap.max_send_wr + 1; sendcq = ib_create_cq(ia->ri_device, rpcrdma_sendcq_upcall, - rpcrdma_cq_async_error_upcall, ep, &cq_attr); + rpcrdma_cq_async_error_upcall, NULL, &cq_attr); if (IS_ERR(sendcq)) { rc = PTR_ERR(sendcq); dprintk("RPC: %s: failed to create send CQ: %i\n", @@ -687,7 +643,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia, 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, ep, &cq_attr); + rpcrdma_cq_async_error_upcall, NULL, &cq_attr); if (IS_ERR(recvcq)) { rc = PTR_ERR(recvcq); dprintk("RPC: %s: failed to create recv CQ: %i\n", @@ -886,7 +842,21 @@ retry: } rc = ep->rep_connected; } else { + struct rpcrdma_xprt *r_xprt; + unsigned int extras; + dprintk("RPC: %s: connected\n", __func__); + + r_xprt = container_of(ia, struct rpcrdma_xprt, rx_ia); + extras = r_xprt->rx_buf.rb_bc_srv_max_requests; + + if (extras) { + rc = rpcrdma_ep_post_extra_recv(r_xprt, extras); + if (rc) + pr_warn("%s: rpcrdma_ep_post_extra_recv: %i\n", + __func__, rc); + rc = 0; + } } out: @@ -923,20 +893,25 @@ rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia) } } -static struct rpcrdma_req * +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); + INIT_LIST_HEAD(&req->rl_free); + 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; return req; } -static struct rpcrdma_rep * +struct rpcrdma_rep * rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data; @@ -958,6 +933,7 @@ rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt) rep->rr_device = ia->ri_device; rep->rr_rxprt = r_xprt; + INIT_WORK(&rep->rr_work, rpcrdma_receive_worker); return rep; out_free: @@ -971,44 +947,21 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt) { struct rpcrdma_buffer *buf = &r_xprt->rx_buf; struct rpcrdma_ia *ia = &r_xprt->rx_ia; - struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data; - char *p; - size_t len; int i, rc; - buf->rb_max_requests = cdata->max_requests; + buf->rb_max_requests = r_xprt->rx_data.max_requests; + buf->rb_bc_srv_max_requests = 0; spin_lock_init(&buf->rb_lock); - /* Need to allocate: - * 1. arrays for send and recv pointers - * 2. arrays of struct rpcrdma_req to fill in pointers - * 3. array of struct rpcrdma_rep for replies - * Send/recv buffers in req/rep need to be registered - */ - len = buf->rb_max_requests * - (sizeof(struct rpcrdma_req *) + sizeof(struct rpcrdma_rep *)); - - p = kzalloc(len, GFP_KERNEL); - if (p == NULL) { - dprintk("RPC: %s: req_t/rep_t/pad kzalloc(%zd) failed\n", - __func__, len); - rc = -ENOMEM; - goto out; - } - buf->rb_pool = p; /* for freeing it later */ - - buf->rb_send_bufs = (struct rpcrdma_req **) p; - p = (char *) &buf->rb_send_bufs[buf->rb_max_requests]; - buf->rb_recv_bufs = (struct rpcrdma_rep **) p; - p = (char *) &buf->rb_recv_bufs[buf->rb_max_requests]; - rc = ia->ri_ops->ro_init(r_xprt); if (rc) goto out; + 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; - struct rpcrdma_rep *rep; req = rpcrdma_create_req(r_xprt); if (IS_ERR(req)) { @@ -1017,7 +970,13 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt) rc = PTR_ERR(req); goto out; } - buf->rb_send_bufs[i] = req; + req->rl_backchannel = false; + list_add(&req->rl_free, &buf->rb_send_bufs); + } + + INIT_LIST_HEAD(&buf->rb_recv_bufs); + for (i = 0; i < buf->rb_max_requests + 2; i++) { + struct rpcrdma_rep *rep; rep = rpcrdma_create_rep(r_xprt); if (IS_ERR(rep)) { @@ -1026,7 +985,7 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt) rc = PTR_ERR(rep); goto out; } - buf->rb_recv_bufs[i] = rep; + list_add(&rep->rr_list, &buf->rb_recv_bufs); } return 0; @@ -1035,22 +994,38 @@ out: 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_free); + list_del(&req->rl_free); + 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_ia *ia, struct rpcrdma_rep *rep) { - if (!rep) - return; - rpcrdma_free_regbuf(ia, rep->rr_rdmabuf); kfree(rep); } -static void +void rpcrdma_destroy_req(struct rpcrdma_ia *ia, struct rpcrdma_req *req) { - if (!req) - return; - rpcrdma_free_regbuf(ia, req->rl_sendbuf); rpcrdma_free_regbuf(ia, req->rl_rdmabuf); kfree(req); @@ -1060,25 +1035,29 @@ void rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf) { struct rpcrdma_ia *ia = rdmab_to_ia(buf); - int i; - /* clean up in reverse order from create - * 1. recv mr memory (mr free, then kfree) - * 2. send mr memory (mr free, then kfree) - * 3. MWs - */ - dprintk("RPC: %s: entering\n", __func__); + while (!list_empty(&buf->rb_recv_bufs)) { + struct rpcrdma_rep *rep; - for (i = 0; i < buf->rb_max_requests; i++) { - if (buf->rb_recv_bufs) - rpcrdma_destroy_rep(ia, buf->rb_recv_bufs[i]); - if (buf->rb_send_bufs) - rpcrdma_destroy_req(ia, buf->rb_send_bufs[i]); + rep = rpcrdma_buffer_get_rep_locked(buf); + rpcrdma_destroy_rep(ia, rep); } - ia->ri_ops->ro_destroy(buf); + 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(ia, req); + spin_lock(&buf->rb_reqslock); + } + spin_unlock(&buf->rb_reqslock); - kfree(buf->rb_pool); + ia->ri_ops->ro_destroy(buf); } struct rpcrdma_mw * @@ -1110,53 +1089,34 @@ rpcrdma_put_mw(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mw *mw) spin_unlock(&buf->rb_mwlock); } -static void -rpcrdma_buffer_put_sendbuf(struct rpcrdma_req *req, struct rpcrdma_buffer *buf) -{ - buf->rb_send_bufs[--buf->rb_send_index] = req; - req->rl_niovs = 0; - if (req->rl_reply) { - buf->rb_recv_bufs[--buf->rb_recv_index] = req->rl_reply; - req->rl_reply = NULL; - } -} - /* * Get a set of request/reply buffers. * - * Reply buffer (if needed) is attached to send buffer upon return. - * Rule: - * rb_send_index and rb_recv_index MUST always be pointing to the - * *next* available buffer (non-NULL). They are incremented after - * removing buffers, and decremented *before* returning them. + * 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; - unsigned long flags; - - spin_lock_irqsave(&buffers->rb_lock, flags); - if (buffers->rb_send_index == buffers->rb_max_requests) { - spin_unlock_irqrestore(&buffers->rb_lock, flags); - dprintk("RPC: %s: out of request buffers\n", __func__); - return ((struct rpcrdma_req *)NULL); - } - - req = buffers->rb_send_bufs[buffers->rb_send_index]; - if (buffers->rb_send_index < buffers->rb_recv_index) { - dprintk("RPC: %s: %d extra receives outstanding (ok)\n", - __func__, - buffers->rb_recv_index - buffers->rb_send_index); - req->rl_reply = NULL; - } else { - req->rl_reply = buffers->rb_recv_bufs[buffers->rb_recv_index]; - buffers->rb_recv_bufs[buffers->rb_recv_index++] = NULL; - } - buffers->rb_send_bufs[buffers->rb_send_index++] = NULL; + spin_lock(&buffers->rb_lock); + if (list_empty(&buffers->rb_send_bufs)) + goto out_reqbuf; + req = rpcrdma_buffer_get_req_locked(buffers); + if (list_empty(&buffers->rb_recv_bufs)) + goto out_repbuf; + req->rl_reply = rpcrdma_buffer_get_rep_locked(buffers); + spin_unlock(&buffers->rb_lock); + return req; - spin_unlock_irqrestore(&buffers->rb_lock, flags); +out_reqbuf: + spin_unlock(&buffers->rb_lock); + pr_warn("RPC: %s: out of request buffers\n", __func__); + return NULL; +out_repbuf: + spin_unlock(&buffers->rb_lock); + pr_warn("RPC: %s: out of reply buffers\n", __func__); + req->rl_reply = NULL; return req; } @@ -1168,30 +1128,31 @@ void rpcrdma_buffer_put(struct rpcrdma_req *req) { struct rpcrdma_buffer *buffers = req->rl_buffer; - unsigned long flags; + struct rpcrdma_rep *rep = req->rl_reply; - spin_lock_irqsave(&buffers->rb_lock, flags); - rpcrdma_buffer_put_sendbuf(req, buffers); - spin_unlock_irqrestore(&buffers->rb_lock, flags); + req->rl_niovs = 0; + req->rl_reply = NULL; + + spin_lock(&buffers->rb_lock); + list_add_tail(&req->rl_free, &buffers->rb_send_bufs); + if (rep) + 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 error conditions. - * Post-increment counter/array index. + * This happens when recovering from disconnect. */ void rpcrdma_recv_buffer_get(struct rpcrdma_req *req) { struct rpcrdma_buffer *buffers = req->rl_buffer; - unsigned long flags; - spin_lock_irqsave(&buffers->rb_lock, flags); - if (buffers->rb_recv_index < buffers->rb_max_requests) { - req->rl_reply = buffers->rb_recv_bufs[buffers->rb_recv_index]; - buffers->rb_recv_bufs[buffers->rb_recv_index++] = NULL; - } - spin_unlock_irqrestore(&buffers->rb_lock, flags); + spin_lock(&buffers->rb_lock); + if (!list_empty(&buffers->rb_recv_bufs)) + req->rl_reply = rpcrdma_buffer_get_rep_locked(buffers); + spin_unlock(&buffers->rb_lock); } /* @@ -1202,11 +1163,10 @@ void rpcrdma_recv_buffer_put(struct rpcrdma_rep *rep) { struct rpcrdma_buffer *buffers = &rep->rr_rxprt->rx_buf; - unsigned long flags; - spin_lock_irqsave(&buffers->rb_lock, flags); - buffers->rb_recv_bufs[--buffers->rb_recv_index] = rep; - spin_unlock_irqrestore(&buffers->rb_lock, flags); + spin_lock(&buffers->rb_lock); + list_add_tail(&rep->rr_list, &buffers->rb_recv_bufs); + spin_unlock(&buffers->rb_lock); } /* @@ -1363,6 +1323,47 @@ rpcrdma_ep_post_recv(struct rpcrdma_ia *ia, return rc; } +/** + * 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_ep *ep = &r_xprt->rx_ep; + struct rpcrdma_rep *rep; + unsigned long flags; + int rc; + + while (count--) { + spin_lock_irqsave(&buffers->rb_lock, flags); + if (list_empty(&buffers->rb_recv_bufs)) + goto out_reqbuf; + rep = rpcrdma_buffer_get_rep_locked(buffers); + spin_unlock_irqrestore(&buffers->rb_lock, flags); + + rc = rpcrdma_ep_post_recv(ia, ep, rep); + if (rc) + goto out_rc; + } + + return 0; + +out_reqbuf: + spin_unlock_irqrestore(&buffers->rb_lock, flags); + pr_warn("%s: no extra receive buffers\n", __func__); + return -ENOMEM; + +out_rc: + rpcrdma_recv_buffer_put(rep); + return rc; +} + /* How many chunk list items fit within our inline buffers? */ unsigned int