@@ -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;
@@ -2262,7 +2296,6 @@ static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,
pr_info("Received CM REJ for ch %s-%d; reason %d; private data %s.\n",
ch->sess_name, ch->qp->qp_num, reason, priv ? : "(?)");
kfree(priv);
- srpt_drain_channel(ch);
}
/**
@@ -2291,40 +2324,6 @@ 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.
@@ -2355,22 +2354,21 @@ 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");
@@ -2510,7 +2508,7 @@ 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);
@@ -2656,16 +2654,16 @@ 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,
@@ -2962,7 +2960,7 @@ 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)
@@ -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;