From: Bart Van Assche Date: Thu, 11 Feb 2016 19:08:53 +0000 (-0800) Subject: IB/srpt: Detect session shutdown reliably X-Git-Tag: v4.6-rc1~102^2~2^3~4 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=aaf45bd83eba804adfa5c4ff5b17ca0c88884c6f;p=platform%2Fkernel%2Flinux-exynos.git IB/srpt: Detect session shutdown reliably The Last WQE Reached event is only generated after one or more work requests have been queued on the QP associated with a session. Since session shutdown can start before any work requests have been queued, use a zero-length RDMA write to wait until a QP has been drained. Additionally, rework the code for closing and disconnecting a session. Signed-off-by: Bart Van Assche Reviewed-by: Christoph Hellwig Cc: Sagi Grimberg Cc: Alex Estrin Signed-off-by: Doug Ledford --- diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c index 33bd408..0881ae9 100644 --- a/drivers/infiniband/ulp/srpt/ib_srpt.c +++ b/drivers/infiniband/ulp/srpt/ib_srpt.c @@ -92,10 +92,11 @@ MODULE_PARM_DESC(srpt_service_guid, static struct ib_client srpt_client; static void srpt_release_cmd(struct se_cmd *se_cmd); -static void srpt_release_channel(struct srpt_rdma_ch *ch); +static void srpt_free_ch(struct kref *kref); static int srpt_queue_status(struct se_cmd *cmd); static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc); static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc); +static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc); /* * The only allowed channel state changes are those that change the channel @@ -175,6 +176,23 @@ static void srpt_srq_event(struct ib_event *event, void *ctx) pr_info("SRQ event %d\n", event->event); } +static const char *get_ch_state_name(enum rdma_ch_state s) +{ + switch (s) { + case CH_CONNECTING: + return "connecting"; + case CH_LIVE: + return "live"; + case CH_DISCONNECTING: + return "disconnecting"; + case CH_DRAINING: + return "draining"; + case CH_DISCONNECTED: + return "disconnected"; + } + return "???"; +} + /** * srpt_qp_event() - QP event callback function. */ @@ -188,11 +206,9 @@ static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch) ib_cm_notify(ch->cm_id, event->event); break; case IB_EVENT_QP_LAST_WQE_REACHED: - if (srpt_set_ch_state(ch, CH_RELEASING)) - srpt_release_channel(ch); - else - pr_debug("%s: state %d - ignored LAST_WQE.\n", - ch->sess_name, ch->state); + pr_debug("%s-%d, state %s: received Last WQE event.\n", + ch->sess_name, ch->qp->qp_num, + get_ch_state_name(ch->state)); break; default: pr_err("received unrecognized IB QP event %d\n", event->event); @@ -795,6 +811,37 @@ out: } /** + * srpt_zerolength_write() - Perform a zero-length RDMA write. + * + * A quote from the InfiniBand specification: C9-88: For an HCA responder + * using Reliable Connection service, for each zero-length RDMA READ or WRITE + * request, the R_Key shall not be validated, even if the request includes + * Immediate data. + */ +static int srpt_zerolength_write(struct srpt_rdma_ch *ch) +{ + struct ib_send_wr wr, *bad_wr; + + memset(&wr, 0, sizeof(wr)); + wr.opcode = IB_WR_RDMA_WRITE; + wr.wr_cqe = &ch->zw_cqe; + wr.send_flags = IB_SEND_SIGNALED; + return ib_post_send(ch->qp, &wr, &bad_wr); +} + +static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc) +{ + struct srpt_rdma_ch *ch = cq->cq_context; + + WARN(wc->status == IB_WC_SUCCESS, "%s-%d: QP not in error state\n", + ch->sess_name, ch->qp->qp_num); + if (srpt_set_ch_state(ch, CH_DISCONNECTED)) + schedule_work(&ch->release_work); + else + WARN_ONCE("%s-%d\n", ch->sess_name, ch->qp->qp_num); +} + +/** * srpt_get_desc_tbl() - Parse the data descriptors of an SRP_CMD request. * @ioctx: Pointer to the I/O context associated with the request. * @srp_cmd: Pointer to the SRP_CMD request data. @@ -1816,110 +1863,102 @@ static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch) } /** - * __srpt_close_ch() - Close an RDMA channel by setting the QP error state. + * srpt_close_ch() - Close an RDMA channel. * - * Reset the QP and make sure all resources associated with the channel will - * be deallocated at an appropriate time. + * Make sure all resources associated with the channel will be deallocated at + * an appropriate time. * - * Note: The caller must hold ch->sport->sdev->spinlock. + * Returns true if and only if the channel state has been modified into + * CH_DRAINING. */ -static void __srpt_close_ch(struct srpt_rdma_ch *ch) +static bool srpt_close_ch(struct srpt_rdma_ch *ch) { - enum rdma_ch_state prev_state; - unsigned long flags; + int ret; - spin_lock_irqsave(&ch->spinlock, flags); - prev_state = ch->state; - switch (prev_state) { - case CH_CONNECTING: - case CH_LIVE: - ch->state = CH_DISCONNECTING; - break; - default: - break; + if (!srpt_set_ch_state(ch, CH_DRAINING)) { + pr_debug("%s-%d: already closed\n", ch->sess_name, + ch->qp->qp_num); + return false; } - spin_unlock_irqrestore(&ch->spinlock, flags); - switch (prev_state) { - case CH_CONNECTING: - ib_send_cm_rej(ch->cm_id, IB_CM_REJ_NO_RESOURCES, NULL, 0, - NULL, 0); - /* fall through */ - case CH_LIVE: - if (ib_send_cm_dreq(ch->cm_id, NULL, 0) < 0) - pr_err("sending CM DREQ failed.\n"); - break; - case CH_DISCONNECTING: - break; - case CH_DRAINING: - case CH_RELEASING: - break; - } -} + kref_get(&ch->kref); -/** - * srpt_close_ch() - Close an RDMA channel. - */ -static void srpt_close_ch(struct srpt_rdma_ch *ch) -{ - struct srpt_device *sdev = ch->sport->sdev; + ret = srpt_ch_qp_err(ch); + if (ret < 0) + pr_err("%s-%d: changing queue pair into error state failed: %d\n", + ch->sess_name, ch->qp->qp_num, ret); - mutex_lock(&sdev->mutex); - __srpt_close_ch(ch); - mutex_unlock(&sdev->mutex); -} + pr_debug("%s-%d: queued zerolength write\n", ch->sess_name, + ch->qp->qp_num); + ret = srpt_zerolength_write(ch); + if (ret < 0) { + pr_err("%s-%d: queuing zero-length write failed: %d\n", + ch->sess_name, ch->qp->qp_num, ret); + if (srpt_set_ch_state(ch, CH_DISCONNECTED)) + schedule_work(&ch->release_work); + else + WARN_ON_ONCE(true); + } -/** - * srpt_shutdown_session() - Whether or not a session may be shut down. - */ -static int srpt_shutdown_session(struct se_session *se_sess) -{ - return 1; + kref_put(&ch->kref, srpt_free_ch); + + return true; } -/** - * srpt_drain_channel() - Drain a channel by resetting the IB queue pair. - * @cm_id: Pointer to the CM ID of the channel to be drained. - * - * Note: Must be called from inside srpt_cm_handler to avoid a race between - * accessing sdev->spinlock and the call to kfree(sdev) in srpt_remove_one() - * (the caller of srpt_cm_handler holds the cm_id spinlock; srpt_remove_one() - * waits until all target sessions for the associated IB device have been - * unregistered and target session registration involves a call to - * ib_destroy_cm_id(), which locks the cm_id spinlock and hence waits until - * this function has finished). +/* + * Change the channel state into CH_DISCONNECTING. If a channel has not yet + * reached the connected state, close it. If a channel is in the connected + * state, send a DREQ. If a DREQ has been received, send a DREP. Note: it is + * the responsibility of the caller to ensure that this function is not + * invoked concurrently with the code that accepts a connection. This means + * that this function must either be invoked from inside a CM callback + * function or that it must be invoked with the srpt_port.mutex held. */ -static void srpt_drain_channel(struct srpt_rdma_ch *ch) +static int srpt_disconnect_ch(struct srpt_rdma_ch *ch) { int ret; - bool do_reset = false; - WARN_ON_ONCE(irqs_disabled()); + if (!srpt_set_ch_state(ch, CH_DISCONNECTING)) + return -ENOTCONN; + + ret = ib_send_cm_dreq(ch->cm_id, NULL, 0); + if (ret < 0) + ret = ib_send_cm_drep(ch->cm_id, NULL, 0); + + if (ret < 0 && srpt_close_ch(ch)) + ret = 0; + + return ret; +} - do_reset = srpt_set_ch_state(ch, CH_DRAINING); +static void __srpt_close_all_ch(struct srpt_device *sdev) +{ + struct srpt_rdma_ch *ch; - if (do_reset) { - if (ch->sess) - srpt_shutdown_session(ch->sess); + lockdep_assert_held(&sdev->mutex); - ret = srpt_ch_qp_err(ch); - if (ret < 0) - pr_err("Setting queue pair in error state" - " failed: %d\n", ret); + list_for_each_entry(ch, &sdev->rch_list, list) { + if (srpt_disconnect_ch(ch) >= 0) + pr_info("Closing channel %s-%d because target %s has been disabled\n", + ch->sess_name, ch->qp->qp_num, + sdev->device->name); + srpt_close_ch(ch); } } /** - * srpt_release_channel() - Release channel resources. - * - * Schedules the actual release because: - * - Calling the ib_destroy_cm_id() call from inside an IB CM callback would - * trigger a deadlock. - * - It is not safe to call TCM transport_* functions from interrupt context. + * srpt_shutdown_session() - Whether or not a session may be shut down. */ -static void srpt_release_channel(struct srpt_rdma_ch *ch) +static int srpt_shutdown_session(struct se_session *se_sess) +{ + return 1; +} + +static void srpt_free_ch(struct kref *kref) { - schedule_work(&ch->release_work); + struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref); + + kfree(ch); } static void srpt_release_channel_work(struct work_struct *w) @@ -1961,7 +2000,7 @@ static void srpt_release_channel_work(struct work_struct *w) wake_up(&sdev->ch_releaseQ); - kfree(ch); + kref_put(&ch->kref, srpt_free_ch); } /** @@ -2046,17 +2085,10 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id, && param->port == ch->sport->port && param->listen_id == ch->sport->sdev->cm_id && ch->cm_id) { - if (ch->state != CH_CONNECTING - && ch->state != CH_LIVE) + if (srpt_disconnect_ch(ch) < 0) continue; - - /* found an existing channel */ - pr_debug("Found existing channel %s" - " cm_id= %p state= %d\n", - ch->sess_name, ch->cm_id, ch->state); - - __srpt_close_ch(ch); - + pr_info("Relogin - closed existing channel %s\n", + ch->sess_name); rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_TERMINATED; } @@ -2087,6 +2119,8 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id, goto reject; } + kref_init(&ch->kref); + ch->zw_cqe.done = srpt_zerolength_write_done; INIT_WORK(&ch->release_work, srpt_release_channel_work); memcpy(ch->i_port_id, req->initiator_port_id, 16); memcpy(ch->t_port_id, req->target_port_id, 16); @@ -2214,7 +2248,7 @@ try_again: goto out; release_channel: - srpt_set_ch_state(ch, CH_RELEASING); + srpt_disconnect_ch(ch); transport_deregister_session_configfs(ch->sess); transport_deregister_session(ch->sess); ch->sess = NULL; @@ -2263,7 +2297,6 @@ static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch, ch->sess_name, ch->qp->qp_num, reason, private_data_len ? "; private data" : "", priv ? priv : " (?)"); kfree(priv); - srpt_drain_channel(ch); } /** @@ -2292,40 +2325,6 @@ static void srpt_cm_rtu_recv(struct srpt_rdma_ch *ch) } /** - * srpt_cm_dreq_recv() - Process reception of a DREQ message. - */ -static void srpt_cm_dreq_recv(struct srpt_rdma_ch *ch) -{ - unsigned long flags; - bool send_drep = false; - - pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num, - ch->state); - - spin_lock_irqsave(&ch->spinlock, flags); - switch (ch->state) { - case CH_CONNECTING: - case CH_LIVE: - send_drep = true; - ch->state = CH_DISCONNECTING; - break; - case CH_DISCONNECTING: - case CH_DRAINING: - case CH_RELEASING: - WARN(true, "unexpected channel state %d\n", ch->state); - break; - } - spin_unlock_irqrestore(&ch->spinlock, flags); - - if (send_drep) { - if (ib_send_cm_drep(ch->cm_id, NULL, 0) < 0) - pr_err("Sending IB DREP failed.\n"); - pr_info("Received DREQ and sent DREP for session %s.\n", - ch->sess_name); - } -} - -/** * srpt_cm_handler() - IB connection manager callback function. * * A non-zero return value will cause the caller destroy the CM ID. @@ -2356,22 +2355,21 @@ static int srpt_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event) srpt_cm_rtu_recv(ch); break; case IB_CM_DREQ_RECEIVED: - srpt_cm_dreq_recv(ch); + srpt_disconnect_ch(ch); break; case IB_CM_DREP_RECEIVED: pr_info("Received CM DREP message for ch %s-%d.\n", ch->sess_name, ch->qp->qp_num); - srpt_drain_channel(ch); + srpt_close_ch(ch); break; case IB_CM_TIMEWAIT_EXIT: pr_info("Received CM TimeWait exit for ch %s-%d.\n", ch->sess_name, ch->qp->qp_num); - srpt_drain_channel(ch); + srpt_close_ch(ch); break; case IB_CM_REP_ERROR: pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name, ch->qp->qp_num); - srpt_drain_channel(ch); break; case IB_CM_DREQ_ERROR: pr_info("Received CM DREQ ERROR event.\n"); @@ -2511,7 +2509,7 @@ static int srpt_write_pending(struct se_cmd *se_cmd) break; case CH_DISCONNECTING: case CH_DRAINING: - case CH_RELEASING: + case CH_DISCONNECTED: pr_debug("cmd with tag %lld: channel disconnecting\n", ioctx->cmd.tag); srpt_set_cmd_state(ioctx, SRPT_STATE_DATA_IN); @@ -2657,16 +2655,16 @@ static void srpt_refresh_port_work(struct work_struct *work) */ static int srpt_release_sdev(struct srpt_device *sdev) { - struct srpt_rdma_ch *ch, *tmp_ch; - int res; + int i, res; WARN_ON_ONCE(irqs_disabled()); BUG_ON(!sdev); mutex_lock(&sdev->mutex); - list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list) - __srpt_close_ch(ch); + for (i = 0; i < ARRAY_SIZE(sdev->port); i++) + sdev->port[i].enabled = false; + __srpt_close_all_ch(sdev); mutex_unlock(&sdev->mutex); res = wait_event_interruptible(sdev->ch_releaseQ, @@ -2963,7 +2961,7 @@ static void srpt_close_session(struct se_session *se_sess) BUG_ON(ch->release_done); ch->release_done = &release_done; wait = !list_empty(&ch->list); - __srpt_close_ch(ch); + srpt_disconnect_ch(ch); mutex_unlock(&sdev->mutex); if (!wait) diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h index 5883295..af9b8b5 100644 --- a/drivers/infiniband/ulp/srpt/ib_srpt.h +++ b/drivers/infiniband/ulp/srpt/ib_srpt.h @@ -218,20 +218,20 @@ struct srpt_send_ioctx { /** * enum rdma_ch_state - SRP channel state. - * @CH_CONNECTING: QP is in RTR state; waiting for RTU. - * @CH_LIVE: QP is in RTS state. - * @CH_DISCONNECTING: DREQ has been received; waiting for DREP - * or DREQ has been send and waiting for DREP - * or . - * @CH_DRAINING: QP is in ERR state; waiting for last WQE event. - * @CH_RELEASING: Last WQE event has been received; releasing resources. + * @CH_CONNECTING: QP is in RTR state; waiting for RTU. + * @CH_LIVE: QP is in RTS state. + * @CH_DISCONNECTING: DREQ has been sent and waiting for DREP or DREQ has + * been received. + * @CH_DRAINING: DREP has been received or waiting for DREP timed out + * and last work request has been queued. + * @CH_DISCONNECTED: Last completion has been received. */ enum rdma_ch_state { CH_CONNECTING, CH_LIVE, CH_DISCONNECTING, CH_DRAINING, - CH_RELEASING + CH_DISCONNECTED, }; /** @@ -267,6 +267,8 @@ struct srpt_rdma_ch { struct ib_cm_id *cm_id; struct ib_qp *qp; struct ib_cq *cq; + struct ib_cqe zw_cqe; + struct kref kref; int rq_size; u32 rsp_size; atomic_t sq_wr_avail;