new file mode 100644
@@ -0,0 +1,2934 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * InfiniBand Transport Layer
+ *
+ * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
+ *
+ * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
+ *
+ * Copyright (c) 2019 1&1 IONOS SE. All rights reserved.
+ */
+
+#undef pr_fmt
+#define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
+
+#include <linux/module.h>
+#include <linux/rculist.h>
+#include <linux/blkdev.h> /* for BLK_MAX_SEGMENT_SIZE */
+
+#include "rtrs-clt.h"
+#include "rtrs-log.h"
+
+#define RTRS_CONNECT_TIMEOUT_MS 30000
+
+MODULE_DESCRIPTION("RTRS Client");
+MODULE_LICENSE("GPL");
+
+static ushort nr_cons_per_session;
+module_param(nr_cons_per_session, ushort, 0444);
+MODULE_PARM_DESC(nr_cons_per_session,
+ "Number of connections per session. (default: nr_cpu_ids)");
+
+static int retry_cnt = 7;
+module_param_named(retry_cnt, retry_cnt, int, 0644);
+MODULE_PARM_DESC(retry_cnt,
+ "Number of times to send the message if the remote side didn't respond with Ack or Nack (default: 7, min: "
+ __stringify(MIN_RTR_CNT) ", max: "
+ __stringify(MAX_RTR_CNT) ")");
+
+static int __read_mostly noreg_cnt;
+module_param_named(noreg_cnt, noreg_cnt, int, 0444);
+MODULE_PARM_DESC(noreg_cnt,
+ "Max number of SG entries when MR registration does not happen (default: 0)");
+
+static const struct rtrs_ib_dev_pool_ops dev_pool_ops;
+static struct rtrs_ib_dev_pool dev_pool = {
+ .ops = &dev_pool_ops
+};
+
+static struct workqueue_struct *rtrs_wq;
+static struct class *rtrs_dev_class;
+
+static inline bool rtrs_clt_is_connected(const struct rtrs_clt *clt)
+{
+ struct rtrs_clt_sess *sess;
+ bool connected = false;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(sess, &clt->paths_list, s.entry)
+ connected |= (READ_ONCE(sess->state) == RTRS_CLT_CONNECTED);
+ rcu_read_unlock();
+
+ return connected;
+}
+
+static inline struct rtrs_permit *
+__rtrs_get_permit(struct rtrs_clt *clt, enum rtrs_clt_con_type con_type)
+{
+ size_t max_depth = clt->queue_depth;
+ struct rtrs_permit *permit;
+ int cpu, bit;
+
+ cpu = get_cpu();
+ do {
+ bit = find_first_zero_bit(clt->permits_map, max_depth);
+ if (unlikely(bit >= max_depth)) {
+ put_cpu();
+ return NULL;
+ }
+
+ } while (unlikely(test_and_set_bit_lock(bit, clt->permits_map)));
+ put_cpu();
+
+ permit = GET_PERMIT(clt, bit);
+ WARN_ON(permit->mem_id != bit);
+ permit->cpu_id = cpu;
+ permit->con_type = con_type;
+
+ return permit;
+}
+
+static inline void __rtrs_put_permit(struct rtrs_clt *clt,
+ struct rtrs_permit *permit)
+{
+ clear_bit_unlock(permit->mem_id, clt->permits_map);
+}
+
+struct rtrs_permit *rtrs_clt_get_permit(struct rtrs_clt *clt,
+ enum rtrs_clt_con_type con_type,
+ int can_wait)
+{
+ struct rtrs_permit *permit;
+ DEFINE_WAIT(wait);
+
+ permit = __rtrs_get_permit(clt, con_type);
+ if (likely(permit) || !can_wait)
+ return permit;
+
+ do {
+ prepare_to_wait(&clt->permits_wait, &wait,
+ TASK_UNINTERRUPTIBLE);
+ permit = __rtrs_get_permit(clt, con_type);
+ if (likely(permit))
+ break;
+
+ io_schedule();
+ } while (1);
+
+ finish_wait(&clt->permits_wait, &wait);
+
+ return permit;
+}
+EXPORT_SYMBOL(rtrs_clt_get_permit);
+
+void rtrs_clt_put_permit(struct rtrs_clt *clt, struct rtrs_permit *permit)
+{
+ if (WARN_ON(!test_bit(permit->mem_id, clt->permits_map)))
+ return;
+
+ __rtrs_put_permit(clt, permit);
+
+ /*
+ * Putting a permit is a barrier, so we will observe
+ * new entry in the wait list, no worries.
+ */
+ if (waitqueue_active(&clt->permits_wait))
+ wake_up(&clt->permits_wait);
+}
+EXPORT_SYMBOL(rtrs_clt_put_permit);
+
+struct rtrs_permit *rtrs_permit_from_pdu(void *pdu)
+{
+ return pdu - sizeof(struct rtrs_permit);
+}
+EXPORT_SYMBOL(rtrs_permit_from_pdu);
+
+void *rtrs_permit_to_pdu(struct rtrs_permit *permit)
+{
+ return permit + 1;
+}
+EXPORT_SYMBOL(rtrs_permit_to_pdu);
+
+/**
+ * rtrs_permit_to_clt_con() - returns RDMA connection id by the permit
+ *
+ * Note:
+ * IO connection starts from 1.
+ * 0 connection is for user messages.
+ */
+static
+struct rtrs_clt_con *rtrs_permit_to_clt_con(struct rtrs_clt_sess *sess,
+ struct rtrs_permit *permit)
+{
+ int id = 0;
+
+ if (likely(permit->con_type == RTRS_IO_CON))
+ id = (permit->cpu_id % (sess->s.con_num - 1)) + 1;
+
+ return to_clt_con(sess->s.con[id]);
+}
+
+static bool __rtrs_clt_change_state(struct rtrs_clt_sess *sess,
+ enum rtrs_clt_state new_state)
+{
+ enum rtrs_clt_state old_state;
+ bool changed = false;
+
+ lockdep_assert_held(&sess->state_wq.lock);
+
+ old_state = sess->state;
+ switch (new_state) {
+ case RTRS_CLT_CONNECTING:
+ switch (old_state) {
+ case RTRS_CLT_RECONNECTING:
+ changed = true;
+ /* FALLTHRU */
+ default:
+ break;
+ }
+ break;
+ case RTRS_CLT_RECONNECTING:
+ switch (old_state) {
+ case RTRS_CLT_CONNECTED:
+ case RTRS_CLT_CONNECTING_ERR:
+ case RTRS_CLT_CLOSED:
+ changed = true;
+ /* FALLTHRU */
+ default:
+ break;
+ }
+ break;
+ case RTRS_CLT_CONNECTED:
+ switch (old_state) {
+ case RTRS_CLT_CONNECTING:
+ changed = true;
+ /* FALLTHRU */
+ default:
+ break;
+ }
+ break;
+ case RTRS_CLT_CONNECTING_ERR:
+ switch (old_state) {
+ case RTRS_CLT_CONNECTING:
+ changed = true;
+ /* FALLTHRU */
+ default:
+ break;
+ }
+ break;
+ case RTRS_CLT_CLOSING:
+ switch (old_state) {
+ case RTRS_CLT_CONNECTING:
+ case RTRS_CLT_CONNECTING_ERR:
+ case RTRS_CLT_RECONNECTING:
+ case RTRS_CLT_CONNECTED:
+ changed = true;
+ /* FALLTHRU */
+ default:
+ break;
+ }
+ break;
+ case RTRS_CLT_CLOSED:
+ switch (old_state) {
+ case RTRS_CLT_CLOSING:
+ changed = true;
+ /* FALLTHRU */
+ default:
+ break;
+ }
+ break;
+ case RTRS_CLT_DEAD:
+ switch (old_state) {
+ case RTRS_CLT_CLOSED:
+ changed = true;
+ /* FALLTHRU */
+ default:
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+ if (changed) {
+ sess->state = new_state;
+ wake_up_locked(&sess->state_wq);
+ }
+
+ return changed;
+}
+
+static bool rtrs_clt_change_state_from_to(struct rtrs_clt_sess *sess,
+ enum rtrs_clt_state old_state,
+ enum rtrs_clt_state new_state)
+{
+ bool changed = false;
+
+ spin_lock_irq(&sess->state_wq.lock);
+ if (sess->state == old_state)
+ changed = __rtrs_clt_change_state(sess, new_state);
+ spin_unlock_irq(&sess->state_wq.lock);
+
+ return changed;
+}
+
+static void rtrs_rdma_error_recovery(struct rtrs_clt_con *con)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+
+ if (rtrs_clt_change_state_from_to(sess,
+ RTRS_CLT_CONNECTED,
+ RTRS_CLT_RECONNECTING)) {
+ /*
+ * Normal scenario, reconnect if we were successfully connected
+ */
+ queue_delayed_work(rtrs_wq, &sess->reconnect_dwork, 0);
+ } else {
+ /*
+ * Error can happen just on establishing new connection,
+ * so notify waiter with error state, waiter is responsible
+ * for cleaning the rest and reconnect if needed.
+ */
+ rtrs_clt_change_state_from_to(sess,
+ RTRS_CLT_CONNECTING,
+ RTRS_CLT_CONNECTING_ERR);
+ }
+}
+
+static void rtrs_clt_fast_reg_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+ struct rtrs_clt_con *con = cq->cq_context;
+
+ if (unlikely(wc->status != IB_WC_SUCCESS)) {
+ rtrs_err(con->c.sess, "Failed IB_WR_REG_MR: %s\n",
+ ib_wc_status_msg(wc->status));
+ rtrs_rdma_error_recovery(con);
+ }
+}
+
+static struct ib_cqe fast_reg_cqe = {
+ .done = rtrs_clt_fast_reg_done
+};
+
+static void complete_rdma_req(struct rtrs_clt_io_req *req, int errno,
+ bool notify, bool can_wait);
+
+static void rtrs_clt_inv_rkey_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+ struct rtrs_clt_io_req *req =
+ container_of(wc->wr_cqe, typeof(*req), inv_cqe);
+ struct rtrs_clt_con *con = cq->cq_context;
+
+ if (unlikely(wc->status != IB_WC_SUCCESS)) {
+ rtrs_err(con->c.sess, "Failed IB_WR_LOCAL_INV: %s\n",
+ ib_wc_status_msg(wc->status));
+ rtrs_rdma_error_recovery(con);
+ }
+ req->need_inv = false;
+ if (likely(req->need_inv_comp))
+ complete(&req->inv_comp);
+ else
+ /* Complete request from INV callback */
+ complete_rdma_req(req, req->inv_errno, true, false);
+}
+
+static int rtrs_inv_rkey(struct rtrs_clt_io_req *req)
+{
+ struct rtrs_clt_con *con = req->con;
+ const struct ib_send_wr *bad_wr;
+ struct ib_send_wr wr = {
+ .opcode = IB_WR_LOCAL_INV,
+ .wr_cqe = &req->inv_cqe,
+ .next = NULL,
+ .num_sge = 0,
+ .send_flags = IB_SEND_SIGNALED,
+ .ex.invalidate_rkey = req->mr->rkey,
+ };
+ req->inv_cqe.done = rtrs_clt_inv_rkey_done;
+
+ return ib_post_send(con->c.qp, &wr, &bad_wr);
+}
+
+static void complete_rdma_req(struct rtrs_clt_io_req *req, int errno,
+ bool notify, bool can_wait)
+{
+ struct rtrs_clt_con *con = req->con;
+ struct rtrs_clt_sess *sess;
+ int err;
+
+ if (WARN_ON(!req->in_use))
+ return;
+ if (WARN_ON(!req->con))
+ return;
+ sess = to_clt_sess(con->c.sess);
+
+ if (req->sg_cnt) {
+ if (unlikely(req->dir == DMA_FROM_DEVICE && req->need_inv)) {
+ /*
+ * We are here to invalidate RDMA read requests
+ * ourselves. In normal scenario server should
+ * send INV for all requested RDMA reads, but
+ * we are here, thus two things could happen:
+ *
+ * 1. this is failover, when errno != 0
+ * and can_wait == 1,
+ *
+ * 2. something totally bad happened and
+ * server forgot to send INV, so we
+ * should do that ourselves.
+ */
+
+ if (likely(can_wait)) {
+ req->need_inv_comp = true;
+ } else {
+ /* This should be IO path, so always notify */
+ WARN_ON(!notify);
+ /* Save errno for INV callback */
+ req->inv_errno = errno;
+ }
+
+ err = rtrs_inv_rkey(req);
+ if (unlikely(err)) {
+ rtrs_err(con->c.sess, "Send INV WR key=%#x: %d\n",
+ req->mr->rkey, err);
+ } else if (likely(can_wait)) {
+ wait_for_completion(&req->inv_comp);
+ } else {
+ /*
+ * Something went wrong, so request will be
+ * completed from INV callback.
+ */
+ WARN_ON_ONCE(1);
+
+ return;
+ }
+ }
+ ib_dma_unmap_sg(sess->s.dev->ib_dev, req->sglist,
+ req->sg_cnt, req->dir);
+ }
+ if (sess->stats.enable_rdma_lat)
+ rtrs_clt_update_rdma_lat(&sess->stats,
+ req->dir == DMA_FROM_DEVICE,
+ jiffies_to_msecs(jiffies -
+ req->start_jiffies));
+ rtrs_clt_decrease_inflight(&sess->stats);
+
+ req->in_use = false;
+ req->con = NULL;
+
+ if (notify)
+ req->conf(req->priv, errno);
+}
+
+static int rtrs_post_send_rdma(struct rtrs_clt_con *con,
+ struct rtrs_clt_io_req *req,
+ struct rtrs_rbuf *rbuf, u32 off,
+ u32 imm, struct ib_send_wr *wr)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ enum ib_send_flags flags;
+ struct ib_sge sge;
+
+ if (unlikely(!req->sg_size)) {
+ rtrs_wrn(con->c.sess,
+ "Doing RDMA Write failed, no data supplied\n");
+ return -EINVAL;
+ }
+
+ /* user data and user message in the first list element */
+ sge.addr = req->iu->dma_addr;
+ sge.length = req->sg_size;
+ sge.lkey = sess->s.dev->ib_pd->local_dma_lkey;
+
+ /*
+ * From time to time we have to post signalled sends,
+ * or send queue will fill up and only QP reset can help.
+ */
+ flags = atomic_inc_return(&con->io_cnt) % sess->queue_depth ?
+ 0 : IB_SEND_SIGNALED;
+
+ ib_dma_sync_single_for_device(sess->s.dev->ib_dev, req->iu->dma_addr,
+ req->sg_size, DMA_TO_DEVICE);
+
+ return rtrs_iu_post_rdma_write_imm(&con->c, req->iu, &sge, 1,
+ rbuf->rkey, rbuf->addr + off,
+ imm, flags, wr);
+}
+
+static void process_io_rsp(struct rtrs_clt_sess *sess, u32 msg_id,
+ s16 errno, bool w_inval)
+{
+ struct rtrs_clt_io_req *req;
+
+ if (WARN_ON(msg_id >= sess->queue_depth))
+ return;
+
+ req = &sess->reqs[msg_id];
+ /* Drop need_inv if server responsed with invalidation */
+ req->need_inv &= !w_inval;
+ complete_rdma_req(req, errno, true, false);
+}
+
+static void rtrs_clt_recv_done(struct rtrs_clt_con *con, struct ib_wc *wc)
+{
+ struct rtrs_iu *iu;
+ int err;
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+
+ WARN_ON(sess->flags != RTRS_MSG_NEW_RKEY_F);
+ iu = container_of(wc->wr_cqe, struct rtrs_iu,
+ cqe);
+ err = rtrs_iu_post_recv(&con->c, iu);
+ if (unlikely(err)) {
+ rtrs_err(con->c.sess, "post iu failed %d\n", err);
+ rtrs_rdma_error_recovery(con);
+ }
+}
+
+static void rtrs_clt_rkey_rsp_done(struct rtrs_clt_con *con, struct ib_wc *wc)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ struct rtrs_msg_rkey_rsp *msg;
+ u32 imm_type, imm_payload;
+ bool w_inval = false;
+ struct rtrs_iu *iu;
+ u32 buf_id;
+ int err;
+
+ WARN_ON(sess->flags != RTRS_MSG_NEW_RKEY_F);
+
+ iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
+
+ if (unlikely(wc->byte_len < sizeof(*msg))) {
+ rtrs_err(con->c.sess, "rkey response is malformed: size %d\n",
+ wc->byte_len);
+ goto out;
+ }
+ ib_dma_sync_single_for_cpu(sess->s.dev->ib_dev, iu->dma_addr,
+ iu->size, DMA_FROM_DEVICE);
+ msg = iu->buf;
+ if (unlikely(le16_to_cpu(msg->type) != RTRS_MSG_RKEY_RSP)) {
+ rtrs_err(sess->clt, "rkey response is malformed: type %d\n",
+ le16_to_cpu(msg->type));
+ goto out;
+ }
+ buf_id = le16_to_cpu(msg->buf_id);
+ if (WARN_ON(buf_id >= sess->queue_depth))
+ goto out;
+
+ rtrs_from_imm(be32_to_cpu(wc->ex.imm_data), &imm_type, &imm_payload);
+ if (likely(imm_type == RTRS_IO_RSP_IMM ||
+ imm_type == RTRS_IO_RSP_W_INV_IMM)) {
+ u32 msg_id;
+
+ w_inval = (imm_type == RTRS_IO_RSP_W_INV_IMM);
+ rtrs_from_io_rsp_imm(imm_payload, &msg_id, &err);
+
+ if (WARN_ON(buf_id != msg_id))
+ goto out;
+ sess->rbufs[buf_id].rkey = le32_to_cpu(msg->rkey);
+ process_io_rsp(sess, msg_id, err, w_inval);
+ }
+ ib_dma_sync_single_for_device(sess->s.dev->ib_dev, iu->dma_addr,
+ iu->size, DMA_FROM_DEVICE);
+ return rtrs_clt_recv_done(con, wc);
+out:
+ rtrs_rdma_error_recovery(con);
+}
+
+static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc);
+
+static struct ib_cqe io_comp_cqe = {
+ .done = rtrs_clt_rdma_done
+};
+
+static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+ struct rtrs_clt_con *con = cq->cq_context;
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ u32 imm_type, imm_payload;
+ bool w_inval = false;
+ int err;
+
+ if (unlikely(wc->status != IB_WC_SUCCESS)) {
+ if (wc->status != IB_WC_WR_FLUSH_ERR) {
+ rtrs_err(sess->clt, "RDMA failed: %s\n",
+ ib_wc_status_msg(wc->status));
+ rtrs_rdma_error_recovery(con);
+ }
+ return;
+ }
+ rtrs_clt_update_wc_stats(con);
+
+ switch (wc->opcode) {
+ case IB_WC_RECV_RDMA_WITH_IMM:
+ /*
+ * post_recv() RDMA write completions of IO reqs (read/write)
+ * and hb
+ */
+ if (WARN_ON(wc->wr_cqe->done != rtrs_clt_rdma_done))
+ return;
+ rtrs_from_imm(be32_to_cpu(wc->ex.imm_data),
+ &imm_type, &imm_payload);
+ if (likely(imm_type == RTRS_IO_RSP_IMM ||
+ imm_type == RTRS_IO_RSP_W_INV_IMM)) {
+ u32 msg_id;
+
+ w_inval = (imm_type == RTRS_IO_RSP_W_INV_IMM);
+ rtrs_from_io_rsp_imm(imm_payload, &msg_id, &err);
+
+ process_io_rsp(sess, msg_id, err, w_inval);
+ } else if (imm_type == RTRS_HB_MSG_IMM) {
+ WARN_ON(con->c.cid);
+ rtrs_send_hb_ack(&sess->s);
+ if (sess->flags == RTRS_MSG_NEW_RKEY_F)
+ return rtrs_clt_recv_done(con, wc);
+ } else if (imm_type == RTRS_HB_ACK_IMM) {
+ WARN_ON(con->c.cid);
+ sess->s.hb_missed_cnt = 0;
+ if (sess->flags == RTRS_MSG_NEW_RKEY_F)
+ return rtrs_clt_recv_done(con, wc);
+ } else {
+ rtrs_wrn(con->c.sess, "Unknown IMM type %u\n",
+ imm_type);
+ }
+ if (w_inval)
+ /*
+ * Post x2 empty WRs: first is for this RDMA with IMM,
+ * second is for RECV with INV, which happened earlier.
+ */
+ err = rtrs_post_recv_empty_x2(&con->c, &io_comp_cqe);
+ else
+ err = rtrs_post_recv_empty(&con->c, &io_comp_cqe);
+ if (unlikely(err)) {
+ rtrs_err(con->c.sess, "rtrs_post_recv_empty(): %d\n",
+ err);
+ rtrs_rdma_error_recovery(con);
+ break;
+ }
+ break;
+ case IB_WC_RECV:
+ /*
+ * Key invalidations from server side
+ */
+ WARN_ON(!(wc->wc_flags & IB_WC_WITH_INVALIDATE ||
+ wc->wc_flags & IB_WC_WITH_IMM));
+ WARN_ON(wc->wr_cqe->done != rtrs_clt_rdma_done);
+ if (sess->flags == RTRS_MSG_NEW_RKEY_F) {
+ if (wc->wc_flags & IB_WC_WITH_INVALIDATE)
+ return rtrs_clt_recv_done(con, wc);
+
+ return rtrs_clt_rkey_rsp_done(con, wc);
+ }
+ break;
+ case IB_WC_RDMA_WRITE:
+ /*
+ * post_send() RDMA write completions of IO reqs (read/write)
+ * and hb
+ */
+ break;
+
+ default:
+ rtrs_wrn(sess->clt, "Unexpected WC type: %d\n", wc->opcode);
+ return;
+ }
+}
+
+static int post_recv_io(struct rtrs_clt_con *con, size_t q_size)
+{
+ int err, i;
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+
+ for (i = 0; i < q_size; i++) {
+ if (sess->flags == RTRS_MSG_NEW_RKEY_F) {
+ struct rtrs_iu *iu = &con->rsp_ius[i];
+
+ err = rtrs_iu_post_recv(&con->c, iu);
+ } else {
+ err = rtrs_post_recv_empty(&con->c, &io_comp_cqe);
+ }
+ if (unlikely(err))
+ return err;
+ }
+
+ return 0;
+}
+
+static int post_recv_sess(struct rtrs_clt_sess *sess)
+{
+ size_t q_size = 0;
+ int err, cid;
+
+ for (cid = 0; cid < sess->s.con_num; cid++) {
+ if (cid == 0)
+ q_size = SERVICE_CON_QUEUE_DEPTH;
+ else
+ q_size = sess->queue_depth;
+
+ /*
+ * x2 for RDMA read responses + FR key invalidations,
+ * RDMA writes do not require any FR registrations.
+ */
+ q_size *= 2;
+
+ err = post_recv_io(to_clt_con(sess->s.con[cid]), q_size);
+ if (unlikely(err)) {
+ rtrs_err(sess->clt, "post_recv_io(), err: %d\n", err);
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+struct path_it {
+ int i;
+ struct list_head skip_list;
+ struct rtrs_clt *clt;
+ struct rtrs_clt_sess *(*next_path)(struct path_it *it);
+};
+
+#define do_each_path(path, clt, it) { \
+ path_it_init(it, clt); \
+ rcu_read_lock(); \
+ for ((it)->i = 0; ((path) = ((it)->next_path)(it)) && \
+ (it)->i < (it)->clt->paths_num; \
+ (it)->i++)
+
+#define while_each_path(it) \
+ path_it_deinit(it); \
+ rcu_read_unlock(); \
+ }
+
+/**
+ * list_next_or_null_rr_rcu - get next list element in round-robin fashion.
+ * @head: the head for the list.
+ * @ptr: the list head to take the next element from.
+ * @type: the type of the struct this is embedded in.
+ * @memb: the name of the list_head within the struct.
+ *
+ * Next element returned in round-robin fashion, i.e. head will be skipped,
+ * but if list is observed as empty, NULL will be returned.
+ *
+ * This primitive may safely run concurrently with the _rcu list-mutation
+ * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
+ */
+#define list_next_or_null_rr_rcu(head, ptr, type, memb) \
+({ \
+ list_next_or_null_rcu(head, ptr, type, memb) ?: \
+ list_next_or_null_rcu(head, READ_ONCE((ptr)->next), \
+ type, memb); \
+})
+
+/**
+ * get_next_path_rr() - Returns path in round-robin fashion.
+ * @it the path pointer
+ *
+ * Related to @MP_POLICY_RR
+ *
+ * Locks:
+ * rcu_read_lock() must be hold.
+ */
+static struct rtrs_clt_sess *get_next_path_rr(struct path_it *it)
+{
+ struct rtrs_clt_sess __rcu **ppcpu_path;
+ struct rtrs_clt_sess *path;
+ struct rtrs_clt *clt;
+
+ clt = it->clt;
+
+ /*
+ * Here we use two RCU objects: @paths_list and @pcpu_path
+ * pointer. See rtrs_clt_remove_path_from_arr() for details
+ * how that is handled.
+ */
+
+ ppcpu_path = this_cpu_ptr(clt->pcpu_path);
+ path = rcu_dereference(*ppcpu_path);
+ if (unlikely(!path))
+ path = list_first_or_null_rcu(&clt->paths_list,
+ typeof(*path), s.entry);
+ else
+ path = list_next_or_null_rr_rcu(&clt->paths_list,
+ &path->s.entry,
+ typeof(*path),
+ s.entry);
+ rcu_assign_pointer(*ppcpu_path, path);
+
+ return path;
+}
+
+/**
+ * get_next_path_min_inflight() - Returns path with minimal inflight count.
+ * @it the path pointer
+ *
+ * Related to @MP_POLICY_MIN_INFLIGHT
+ *
+ * Locks:
+ * rcu_read_lock() must be hold.
+ */
+static struct rtrs_clt_sess *get_next_path_min_inflight(struct path_it *it)
+{
+ struct rtrs_clt_sess *min_path = NULL;
+ struct rtrs_clt *clt = it->clt;
+ struct rtrs_clt_sess *sess;
+ int min_inflight = INT_MAX;
+ int inflight;
+
+ list_for_each_entry_rcu(sess, &clt->paths_list, s.entry) {
+ if (unlikely(!list_empty(raw_cpu_ptr(sess->mp_skip_entry))))
+ continue;
+
+ inflight = atomic_read(&sess->stats.inflight);
+
+ if (inflight < min_inflight) {
+ min_inflight = inflight;
+ min_path = sess;
+ }
+ }
+
+ /*
+ * add the path to the skip list, so that next time we can get
+ * a different one
+ */
+ if (min_path)
+ list_add(raw_cpu_ptr(min_path->mp_skip_entry), &it->skip_list);
+
+ return min_path;
+}
+
+static inline void path_it_init(struct path_it *it, struct rtrs_clt *clt)
+{
+ INIT_LIST_HEAD(&it->skip_list);
+ it->clt = clt;
+ it->i = 0;
+
+ if (clt->mp_policy == MP_POLICY_RR)
+ it->next_path = get_next_path_rr;
+ else
+ it->next_path = get_next_path_min_inflight;
+}
+
+static inline void path_it_deinit(struct path_it *it)
+{
+ struct list_head *skip, *tmp;
+ /*
+ * The skip_list is used only for the MIN_INFLIGHT policy.
+ * We need to remove paths from it, so that next IO can insert
+ * paths (->mp_skip_entry) into a skip_list again.
+ */
+ list_for_each_safe(skip, tmp, &it->skip_list)
+ list_del_init(skip);
+}
+
+/**
+ * rtrs_clt_init_req() Initialize an rtrs_clt_io_req holding information
+ * about an inflight IO.
+ * The user buffer holding user control message (not data) is copied into
+ * the corresponding buffer of rtrs_iu (req->iu->buf), which later on will
+ * also hold the control message of rtrs.
+ */
+static inline void rtrs_clt_init_req(struct rtrs_clt_io_req *req,
+ struct rtrs_clt_sess *sess,
+ rtrs_conf_fn *conf,
+ struct rtrs_permit *permit, void *priv,
+ const struct kvec *vec, size_t usr_len,
+ struct scatterlist *sg, size_t sg_cnt,
+ size_t data_len, int dir)
+{
+ struct iov_iter iter;
+ size_t len;
+
+ req->permit = permit;
+ req->in_use = true;
+ req->usr_len = usr_len;
+ req->data_len = data_len;
+ req->sglist = sg;
+ req->sg_cnt = sg_cnt;
+ req->priv = priv;
+ req->dir = dir;
+ req->con = rtrs_permit_to_clt_con(sess, permit);
+ req->conf = conf;
+ req->need_inv = false;
+ req->need_inv_comp = false;
+ req->inv_errno = 0;
+
+ iov_iter_kvec(&iter, READ, vec, 1, usr_len);
+ len = _copy_from_iter(req->iu->buf, usr_len, &iter);
+ WARN_ON(len != usr_len);
+
+ reinit_completion(&req->inv_comp);
+ if (sess->stats.enable_rdma_lat)
+ req->start_jiffies = jiffies;
+}
+
+static inline struct rtrs_clt_io_req *
+rtrs_clt_get_req(struct rtrs_clt_sess *sess, rtrs_conf_fn *conf,
+ struct rtrs_permit *permit, void *priv,
+ const struct kvec *vec, size_t usr_len,
+ struct scatterlist *sg, size_t sg_cnt,
+ size_t data_len, int dir)
+{
+ struct rtrs_clt_io_req *req;
+
+ req = &sess->reqs[permit->mem_id];
+ rtrs_clt_init_req(req, sess, conf, permit, priv, vec, usr_len,
+ sg, sg_cnt, data_len, dir);
+ return req;
+}
+
+static inline struct rtrs_clt_io_req *
+rtrs_clt_get_copy_req(struct rtrs_clt_sess *alive_sess,
+ struct rtrs_clt_io_req *fail_req)
+{
+ struct rtrs_clt_io_req *req;
+ struct kvec vec = {
+ .iov_base = fail_req->iu->buf,
+ .iov_len = fail_req->usr_len
+ };
+
+ req = &alive_sess->reqs[fail_req->permit->mem_id];
+ rtrs_clt_init_req(req, alive_sess, fail_req->conf, fail_req->permit,
+ fail_req->priv, &vec, fail_req->usr_len,
+ fail_req->sglist, fail_req->sg_cnt,
+ fail_req->data_len, fail_req->dir);
+ return req;
+}
+
+static int rtrs_post_rdma_write_sg(struct rtrs_clt_con *con,
+ struct rtrs_clt_io_req *req,
+ struct rtrs_rbuf *rbuf,
+ u32 size, u32 imm)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ struct ib_sge *sge = req->sge;
+ enum ib_send_flags flags;
+ struct scatterlist *sg;
+ size_t num_sge;
+ int i;
+
+ for_each_sg(req->sglist, sg, req->sg_cnt, i) {
+ sge[i].addr = sg_dma_address(sg);
+ sge[i].length = sg_dma_len(sg);
+ sge[i].lkey = sess->s.dev->ib_pd->local_dma_lkey;
+ }
+ sge[i].addr = req->iu->dma_addr;
+ sge[i].length = size;
+ sge[i].lkey = sess->s.dev->ib_pd->local_dma_lkey;
+
+ num_sge = 1 + req->sg_cnt;
+
+ /*
+ * From time to time we have to post signalled sends,
+ * or send queue will fill up and only QP reset can help.
+ */
+ flags = atomic_inc_return(&con->io_cnt) % sess->queue_depth ?
+ 0 : IB_SEND_SIGNALED;
+
+ ib_dma_sync_single_for_device(sess->s.dev->ib_dev, req->iu->dma_addr,
+ size, DMA_TO_DEVICE);
+
+ return rtrs_iu_post_rdma_write_imm(&con->c, req->iu, sge, num_sge,
+ rbuf->rkey, rbuf->addr, imm,
+ flags, NULL);
+}
+
+static int rtrs_clt_write_req(struct rtrs_clt_io_req *req)
+{
+ struct rtrs_clt_con *con = req->con;
+ struct rtrs_sess *s = con->c.sess;
+ struct rtrs_clt_sess *sess = to_clt_sess(s);
+ struct rtrs_msg_rdma_write *msg;
+
+ struct rtrs_rbuf *rbuf;
+ int ret, count = 0;
+ u32 imm, buf_id;
+
+ const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len;
+
+ if (unlikely(tsize > sess->chunk_size)) {
+ rtrs_wrn(s, "Write request failed, size too big %zu > %d\n",
+ tsize, sess->chunk_size);
+ return -EMSGSIZE;
+ }
+ if (req->sg_cnt) {
+ count = ib_dma_map_sg(sess->s.dev->ib_dev, req->sglist,
+ req->sg_cnt, req->dir);
+ if (unlikely(!count)) {
+ rtrs_wrn(s, "Write request failed, map failed\n");
+ return -EINVAL;
+ }
+ }
+ /* put rtrs msg after sg and user message */
+ msg = req->iu->buf + req->usr_len;
+ msg->type = cpu_to_le16(RTRS_MSG_WRITE);
+ msg->usr_len = cpu_to_le16(req->usr_len);
+
+ /* rtrs message on server side will be after user data and message */
+ imm = req->permit->mem_off + req->data_len + req->usr_len;
+ imm = rtrs_to_io_req_imm(imm);
+ buf_id = req->permit->mem_id;
+ req->sg_size = tsize;
+ rbuf = &sess->rbufs[buf_id];
+
+ /*
+ * Update stats now, after request is successfully sent it is not
+ * safe anymore to touch it.
+ */
+ rtrs_clt_update_all_stats(req, WRITE);
+
+ ret = rtrs_post_rdma_write_sg(req->con, req, rbuf,
+ req->usr_len + sizeof(*msg),
+ imm);
+ if (unlikely(ret)) {
+ rtrs_err(s, "Write request failed: %d\n", ret);
+ rtrs_clt_decrease_inflight(&sess->stats);
+ if (req->sg_cnt)
+ ib_dma_unmap_sg(sess->s.dev->ib_dev, req->sglist,
+ req->sg_cnt, req->dir);
+ }
+
+ return ret;
+}
+
+static int rtrs_map_sg_fr(struct rtrs_clt_io_req *req, size_t count)
+{
+ int nr;
+
+ /* Align the MR to a 4K page size to match the block virt boundary */
+ nr = ib_map_mr_sg(req->mr, req->sglist, count, NULL, SZ_4K);
+ if (unlikely(nr < req->sg_cnt)) {
+ if (nr < 0)
+ return nr;
+ return -EINVAL;
+ }
+ ib_update_fast_reg_key(req->mr, ib_inc_rkey(req->mr->rkey));
+
+ return nr;
+}
+
+static int rtrs_clt_read_req(struct rtrs_clt_io_req *req)
+{
+ struct rtrs_clt_con *con = req->con;
+ struct rtrs_sess *s = con->c.sess;
+ struct rtrs_clt_sess *sess = to_clt_sess(s);
+ struct rtrs_msg_rdma_read *msg;
+ struct rtrs_ib_dev *dev;
+ struct scatterlist *sg;
+
+ struct ib_reg_wr rwr;
+ struct ib_send_wr *wr = NULL;
+
+ int i, ret, count = 0;
+ u32 imm, buf_id;
+
+ const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len;
+
+ s = &sess->s;
+ dev = sess->s.dev;
+
+ if (unlikely(tsize > sess->chunk_size)) {
+ rtrs_wrn(s,
+ "Read request failed, message size is %zu, bigger than CHUNK_SIZE %d\n",
+ tsize, sess->chunk_size);
+ return -EMSGSIZE;
+ }
+
+ if (req->sg_cnt) {
+ count = ib_dma_map_sg(dev->ib_dev, req->sglist, req->sg_cnt,
+ req->dir);
+ if (unlikely(!count)) {
+ rtrs_wrn(s,
+ "Read request failed, dma map failed\n");
+ return -EINVAL;
+ }
+ }
+ /* put our message into req->buf after user message*/
+ msg = req->iu->buf + req->usr_len;
+ msg->type = cpu_to_le16(RTRS_MSG_READ);
+ msg->usr_len = cpu_to_le16(req->usr_len);
+
+ if (count > noreg_cnt) {
+ ret = rtrs_map_sg_fr(req, count);
+ if (ret < 0) {
+ rtrs_err_rl(s,
+ "Read request failed, failed to map fast reg. data, err: %d\n",
+ ret);
+ ib_dma_unmap_sg(dev->ib_dev, req->sglist, req->sg_cnt,
+ req->dir);
+ return ret;
+ }
+ memset(&rwr, 0, sizeof(rwr));
+ rwr.wr.next = NULL;
+ rwr.wr.opcode = IB_WR_REG_MR;
+ rwr.wr.wr_cqe = &fast_reg_cqe;
+ rwr.wr.num_sge = 0;
+ rwr.mr = req->mr;
+ rwr.key = req->mr->rkey;
+ rwr.access = (IB_ACCESS_LOCAL_WRITE |
+ IB_ACCESS_REMOTE_WRITE);
+ wr = &rwr.wr;
+
+ msg->sg_cnt = cpu_to_le16(1);
+ msg->flags = cpu_to_le16(RTRS_MSG_NEED_INVAL_F);
+
+ msg->desc[0].addr = cpu_to_le64(req->mr->iova);
+ msg->desc[0].key = cpu_to_le32(req->mr->rkey);
+ msg->desc[0].len = cpu_to_le32(req->mr->length);
+
+ /* Further invalidation is required */
+ req->need_inv = !!RTRS_MSG_NEED_INVAL_F;
+
+ } else {
+ msg->sg_cnt = cpu_to_le16(count);
+ msg->flags = 0;
+
+ for_each_sg(req->sglist, sg, req->sg_cnt, i) {
+ msg->desc[i].addr = cpu_to_le64(sg_dma_address(sg));
+ msg->desc[i].key =
+ cpu_to_le32(dev->ib_pd->unsafe_global_rkey);
+ msg->desc[i].len = cpu_to_le32(sg_dma_len(sg));
+ }
+ }
+ /*
+ * rtrs message will be after the space reserved for disk data and
+ * user message
+ */
+ imm = req->permit->mem_off + req->data_len + req->usr_len;
+ imm = rtrs_to_io_req_imm(imm);
+ buf_id = req->permit->mem_id;
+
+ req->sg_size = sizeof(*msg);
+ req->sg_size += le16_to_cpu(msg->sg_cnt) * sizeof(struct rtrs_sg_desc);
+ req->sg_size += req->usr_len;
+
+ /*
+ * Update stats now, after request is successfully sent it is not
+ * safe anymore to touch it.
+ */
+ rtrs_clt_update_all_stats(req, READ);
+
+ ret = rtrs_post_send_rdma(req->con, req, &sess->rbufs[buf_id],
+ req->data_len, imm, wr);
+ if (unlikely(ret)) {
+ rtrs_err(s, "Read request failed: %d\n", ret);
+ rtrs_clt_decrease_inflight(&sess->stats);
+ req->need_inv = false;
+ if (req->sg_cnt)
+ ib_dma_unmap_sg(dev->ib_dev, req->sglist,
+ req->sg_cnt, req->dir);
+ }
+
+ return ret;
+}
+
+/**
+ * rtrs_clt_failover_req() Try to find an active path for a failed request
+ */
+static int rtrs_clt_failover_req(struct rtrs_clt *clt,
+ struct rtrs_clt_io_req *fail_req)
+{
+ struct rtrs_clt_sess *alive_sess;
+ struct rtrs_clt_io_req *req;
+ int err = -ECONNABORTED;
+ struct path_it it;
+
+ do_each_path(alive_sess, clt, &it) {
+ if (unlikely(READ_ONCE(alive_sess->state) !=
+ RTRS_CLT_CONNECTED))
+ continue;
+ req = rtrs_clt_get_copy_req(alive_sess, fail_req);
+ if (req->dir == DMA_TO_DEVICE)
+ err = rtrs_clt_write_req(req);
+ else
+ err = rtrs_clt_read_req(req);
+ if (unlikely(err)) {
+ req->in_use = false;
+ continue;
+ }
+ /* Success path */
+ rtrs_clt_inc_failover_cnt(&alive_sess->stats);
+ break;
+ } while_each_path(&it);
+
+ return err;
+}
+
+static void fail_all_outstanding_reqs(struct rtrs_clt_sess *sess)
+{
+ struct rtrs_clt *clt = sess->clt;
+ struct rtrs_clt_io_req *req;
+ int i, err;
+
+ if (!sess->reqs)
+ return;
+ for (i = 0; i < sess->queue_depth; ++i) {
+ req = &sess->reqs[i];
+ if (!req->in_use)
+ continue;
+
+ /*
+ * Safely (without notification) complete failed request.
+ * After completion this request is still useble and can
+ * be failovered to another path.
+ */
+ complete_rdma_req(req, -ECONNABORTED, false, true);
+
+ err = rtrs_clt_failover_req(clt, req);
+ if (unlikely(err))
+ /* Failover failed, notify anyway */
+ req->conf(req->priv, err);
+ }
+}
+
+static void free_sess_reqs(struct rtrs_clt_sess *sess)
+{
+ struct rtrs_clt_io_req *req;
+ int i;
+
+ if (!sess->reqs)
+ return;
+ for (i = 0; i < sess->queue_depth; ++i) {
+ req = &sess->reqs[i];
+ if (req->mr)
+ ib_dereg_mr(req->mr);
+ kfree(req->sge);
+ rtrs_iu_free(req->iu, DMA_TO_DEVICE,
+ sess->s.dev->ib_dev, 1);
+ }
+ kfree(sess->reqs);
+ sess->reqs = NULL;
+}
+
+static int alloc_sess_reqs(struct rtrs_clt_sess *sess)
+{
+ struct rtrs_clt_io_req *req;
+ struct rtrs_clt *clt = sess->clt;
+ int i, err = -ENOMEM;
+
+ sess->reqs = kcalloc(sess->queue_depth, sizeof(*sess->reqs),
+ GFP_KERNEL);
+ if (unlikely(!sess->reqs))
+ return -ENOMEM;
+
+ for (i = 0; i < sess->queue_depth; ++i) {
+ req = &sess->reqs[i];
+ req->iu = rtrs_iu_alloc(1, sess->max_hdr_size, GFP_KERNEL,
+ sess->s.dev->ib_dev,
+ DMA_TO_DEVICE,
+ rtrs_clt_rdma_done);
+ if (unlikely(!req->iu))
+ goto out;
+
+ req->sge = kmalloc_array(clt->max_segments + 1,
+ sizeof(*req->sge), GFP_KERNEL);
+ if (unlikely(!req->sge))
+ goto out;
+
+ req->mr = ib_alloc_mr(sess->s.dev->ib_pd, IB_MR_TYPE_MEM_REG,
+ sess->max_pages_per_mr);
+ if (IS_ERR(req->mr)) {
+ err = PTR_ERR(req->mr);
+ req->mr = NULL;
+ pr_err("Failed to alloc sess->max_pages_per_mr %d\n",
+ sess->max_pages_per_mr);
+ goto out;
+ }
+
+ init_completion(&req->inv_comp);
+ }
+
+ return 0;
+
+out:
+ free_sess_reqs(sess);
+
+ return err;
+}
+
+static int alloc_permits(struct rtrs_clt *clt)
+{
+ unsigned int chunk_bits;
+ int err, i;
+
+ clt->permits_map = kcalloc(BITS_TO_LONGS(clt->queue_depth),
+ sizeof(long), GFP_KERNEL);
+ if (unlikely(!clt->permits_map)) {
+ err = -ENOMEM;
+ goto out_err;
+ }
+ clt->permits = kcalloc(clt->queue_depth, PERMIT_SIZE(clt), GFP_KERNEL);
+ if (unlikely(!clt->permits)) {
+ err = -ENOMEM;
+ goto err_map;
+ }
+ chunk_bits = ilog2(clt->queue_depth - 1) + 1;
+ for (i = 0; i < clt->queue_depth; i++) {
+ struct rtrs_permit *permit;
+
+ permit = GET_PERMIT(clt, i);
+ permit->mem_id = i;
+ permit->mem_off = i << (MAX_IMM_PAYL_BITS - chunk_bits);
+ }
+
+ return 0;
+
+err_map:
+ kfree(clt->permits_map);
+ clt->permits_map = NULL;
+out_err:
+ return err;
+}
+
+static void free_permits(struct rtrs_clt *clt)
+{
+ kfree(clt->permits_map);
+ clt->permits_map = NULL;
+ kfree(clt->permits);
+ clt->permits = NULL;
+}
+
+static void query_fast_reg_mode(struct rtrs_clt_sess *sess)
+{
+ struct ib_device *ib_dev;
+ u64 max_pages_per_mr;
+ int mr_page_shift;
+
+ ib_dev = sess->s.dev->ib_dev;
+
+ /*
+ * Use the smallest page size supported by the HCA, down to a
+ * minimum of 4096 bytes. We're unlikely to build large sglists
+ * out of smaller entries.
+ */
+ mr_page_shift = max(12, ffs(ib_dev->attrs.page_size_cap) - 1);
+ max_pages_per_mr = ib_dev->attrs.max_mr_size;
+ do_div(max_pages_per_mr, (1ull << mr_page_shift));
+ sess->max_pages_per_mr =
+ min3(sess->max_pages_per_mr, (u32)max_pages_per_mr,
+ ib_dev->attrs.max_fast_reg_page_list_len);
+ sess->max_send_sge = ib_dev->attrs.max_send_sge;
+}
+
+static bool rtrs_clt_change_state_get_old(struct rtrs_clt_sess *sess,
+ enum rtrs_clt_state new_state,
+ enum rtrs_clt_state *old_state)
+{
+ bool changed;
+
+ spin_lock_irq(&sess->state_wq.lock);
+ *old_state = sess->state;
+ changed = __rtrs_clt_change_state(sess, new_state);
+ spin_unlock_irq(&sess->state_wq.lock);
+
+ return changed;
+}
+
+static bool rtrs_clt_change_state(struct rtrs_clt_sess *sess,
+ enum rtrs_clt_state new_state)
+{
+ enum rtrs_clt_state old_state;
+
+ return rtrs_clt_change_state_get_old(sess, new_state, &old_state);
+}
+
+static void rtrs_clt_hb_err_handler(struct rtrs_con *c)
+{
+ struct rtrs_clt_con *con = container_of(c, typeof(*con), c);
+
+ rtrs_rdma_error_recovery(con);
+}
+
+static void rtrs_clt_init_hb(struct rtrs_clt_sess *sess)
+{
+ rtrs_init_hb(&sess->s, &io_comp_cqe,
+ RTRS_HB_INTERVAL_MS,
+ RTRS_HB_MISSED_MAX,
+ rtrs_clt_hb_err_handler,
+ rtrs_wq);
+}
+
+static void rtrs_clt_start_hb(struct rtrs_clt_sess *sess)
+{
+ rtrs_start_hb(&sess->s);
+}
+
+static void rtrs_clt_stop_hb(struct rtrs_clt_sess *sess)
+{
+ rtrs_stop_hb(&sess->s);
+}
+
+static void rtrs_clt_reconnect_work(struct work_struct *work);
+static void rtrs_clt_close_work(struct work_struct *work);
+
+static struct rtrs_clt_sess *alloc_sess(struct rtrs_clt *clt,
+ const struct rtrs_addr *path,
+ size_t con_num, u16 max_segments)
+{
+ struct rtrs_clt_sess *sess;
+ int err = -ENOMEM;
+ int cpu;
+
+ sess = kzalloc(sizeof(*sess), GFP_KERNEL);
+ if (unlikely(!sess))
+ goto err;
+
+ /* Extra connection for user messages */
+ con_num += 1;
+
+ sess->s.con = kcalloc(con_num, sizeof(*sess->s.con), GFP_KERNEL);
+ if (unlikely(!sess->s.con))
+ goto err_free_sess;
+
+ mutex_init(&sess->init_mutex);
+ uuid_gen(&sess->s.uuid);
+ memcpy(&sess->s.dst_addr, path->dst,
+ rdma_addr_size((struct sockaddr *)path->dst));
+
+ /*
+ * rdma_resolve_addr() passes src_addr to cma_bind_addr, which
+ * checks the sa_family to be non-zero. If user passed src_addr=NULL
+ * the sess->src_addr will contain only zeros, which is then fine.
+ */
+ if (path->src)
+ memcpy(&sess->s.src_addr, path->src,
+ rdma_addr_size((struct sockaddr *)path->src));
+ strlcpy(sess->s.sessname, clt->sessname, sizeof(sess->s.sessname));
+ sess->s.con_num = con_num;
+ sess->clt = clt;
+ sess->max_pages_per_mr = max_segments * BLK_MAX_SEGMENT_SIZE >> 12;
+ init_waitqueue_head(&sess->state_wq);
+ sess->state = RTRS_CLT_CONNECTING;
+ atomic_set(&sess->connected_cnt, 0);
+ INIT_WORK(&sess->close_work, rtrs_clt_close_work);
+ INIT_DELAYED_WORK(&sess->reconnect_dwork, rtrs_clt_reconnect_work);
+ rtrs_clt_init_hb(sess);
+
+ sess->mp_skip_entry = alloc_percpu(typeof(*sess->mp_skip_entry));
+ if (unlikely(!sess->mp_skip_entry))
+ goto err_free_con;
+
+ for_each_possible_cpu(cpu)
+ INIT_LIST_HEAD(per_cpu_ptr(sess->mp_skip_entry, cpu));
+
+ err = rtrs_clt_init_stats(&sess->stats);
+ if (unlikely(err))
+ goto err_free_percpu;
+
+ return sess;
+
+err_free_percpu:
+ free_percpu(sess->mp_skip_entry);
+err_free_con:
+ kfree(sess->s.con);
+err_free_sess:
+ kfree(sess);
+err:
+ return ERR_PTR(err);
+}
+
+static void free_sess(struct rtrs_clt_sess *sess)
+{
+ rtrs_clt_free_stats(&sess->stats);
+ free_percpu(sess->mp_skip_entry);
+ kfree(sess->s.con);
+ kfree(sess->rbufs);
+ kfree(sess);
+}
+
+static int create_con(struct rtrs_clt_sess *sess, unsigned int cid)
+{
+ struct rtrs_clt_con *con;
+
+ con = kzalloc(sizeof(*con), GFP_KERNEL);
+ if (unlikely(!con))
+ return -ENOMEM;
+
+ /* Map first two connections to the first CPU */
+ con->cpu = (cid ? cid - 1 : 0) % nr_cpu_ids;
+ con->c.cid = cid;
+ con->c.sess = &sess->s;
+ atomic_set(&con->io_cnt, 0);
+
+ sess->s.con[cid] = &con->c;
+
+ return 0;
+}
+
+static void destroy_con(struct rtrs_clt_con *con)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+
+ sess->s.con[con->c.cid] = NULL;
+ kfree(con);
+}
+
+static int create_con_cq_qp(struct rtrs_clt_con *con)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ u16 wr_queue_size;
+ int err, cq_vector;
+ struct rtrs_msg_rkey_rsp *rsp;
+
+ /*
+ * This function can fail, but still destroy_con_cq_qp() should
+ * be called, this is because create_con_cq_qp() is called on cm
+ * event path, thus caller/waiter never knows: have we failed before
+ * create_con_cq_qp() or after. To solve this dilemma without
+ * creating any additional flags just allow destroy_con_cq_qp() be
+ * called many times.
+ */
+
+ if (con->c.cid == 0) {
+ /*
+ * One completion for each receive and two for each send
+ * (send request + registration)
+ * + 2 for drain and heartbeat
+ * in case qp gets into error state
+ */
+ wr_queue_size = SERVICE_CON_QUEUE_DEPTH * 3 + 2;
+ /* We must be the first here */
+ if (WARN_ON(sess->s.dev))
+ return -EINVAL;
+
+ /*
+ * The whole session uses device from user connection.
+ * Be careful not to close user connection before ib dev
+ * is gracefully put.
+ */
+ sess->s.dev = rtrs_ib_dev_find_or_add(con->c.cm_id->device,
+ &dev_pool);
+ if (unlikely(!sess->s.dev)) {
+ rtrs_wrn(sess->clt,
+ "rtrs_ib_dev_find_get_or_add(): no memory\n");
+ return -ENOMEM;
+ }
+ sess->s.dev_ref = 1;
+ query_fast_reg_mode(sess);
+ } else {
+ /*
+ * Here we assume that session members are correctly set.
+ * This is always true if user connection (cid == 0) is
+ * established first.
+ */
+ if (WARN_ON(!sess->s.dev))
+ return -EINVAL;
+ if (WARN_ON(!sess->queue_depth))
+ return -EINVAL;
+
+ /* Shared between connections */
+ sess->s.dev_ref++;
+ wr_queue_size =
+ min_t(int, sess->s.dev->ib_dev->attrs.max_qp_wr,
+ /* QD * (REQ + RSP + FR REGS or INVS) + drain */
+ sess->queue_depth * 3 + 1);
+ }
+ /* alloc iu to recv new rkey reply when server reports flags set */
+ if (sess->flags == RTRS_MSG_NEW_RKEY_F || con->c.cid == 0) {
+ con->rsp_ius = rtrs_iu_alloc(wr_queue_size, sizeof(*rsp),
+ GFP_KERNEL, sess->s.dev->ib_dev,
+ DMA_FROM_DEVICE,
+ rtrs_clt_rdma_done);
+ if (unlikely(!con->rsp_ius))
+ return -ENOMEM;
+ con->queue_size = wr_queue_size;
+ }
+ cq_vector = con->cpu % sess->s.dev->ib_dev->num_comp_vectors;
+ err = rtrs_cq_qp_create(&sess->s, &con->c, sess->max_send_sge,
+ cq_vector, wr_queue_size, wr_queue_size,
+ IB_POLL_SOFTIRQ);
+ /*
+ * In case of error we do not bother to clean previous allocations,
+ * since destroy_con_cq_qp() must be called.
+ */
+
+ if (unlikely(err))
+ return err;
+ return err;
+}
+
+static void destroy_con_cq_qp(struct rtrs_clt_con *con)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+
+ /*
+ * Be careful here: destroy_con_cq_qp() can be called even
+ * create_con_cq_qp() failed, see comments there.
+ */
+
+ rtrs_cq_qp_destroy(&con->c);
+ if (con->rsp_ius) {
+ rtrs_iu_free(con->rsp_ius, DMA_FROM_DEVICE,
+ sess->s.dev->ib_dev, con->queue_size);
+ con->rsp_ius = NULL;
+ con->queue_size = 0;
+ }
+ if (sess->s.dev_ref && !--sess->s.dev_ref) {
+ rtrs_ib_dev_put(sess->s.dev);
+ sess->s.dev = NULL;
+ }
+}
+
+static void stop_cm(struct rtrs_clt_con *con)
+{
+ rdma_disconnect(con->c.cm_id);
+ if (con->c.qp)
+ ib_drain_qp(con->c.qp);
+}
+
+static void destroy_cm(struct rtrs_clt_con *con)
+{
+ rdma_destroy_id(con->c.cm_id);
+ con->c.cm_id = NULL;
+}
+
+static int rtrs_rdma_addr_resolved(struct rtrs_clt_con *con)
+{
+ struct rtrs_sess *s = con->c.sess;
+ int err;
+
+ err = create_con_cq_qp(con);
+ if (unlikely(err)) {
+ rtrs_err(s, "create_con_cq_qp(), err: %d\n", err);
+ return err;
+ }
+ err = rdma_resolve_route(con->c.cm_id, RTRS_CONNECT_TIMEOUT_MS);
+ if (unlikely(err)) {
+ rtrs_err(s, "Resolving route failed, err: %d\n", err);
+ destroy_con_cq_qp(con);
+ }
+
+ return err;
+}
+
+static int rtrs_rdma_route_resolved(struct rtrs_clt_con *con)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ struct rtrs_clt *clt = sess->clt;
+ struct rtrs_msg_conn_req msg;
+ struct rdma_conn_param param;
+
+ int err;
+
+ memset(¶m, 0, sizeof(param));
+ param.retry_count = clamp(retry_cnt, MIN_RTR_CNT, MAX_RTR_CNT);
+ param.rnr_retry_count = 7;
+ param.private_data = &msg;
+ param.private_data_len = sizeof(msg);
+
+ /*
+ * Those two are the part of struct cma_hdr which is shared
+ * with private_data in case of AF_IB, so put zeroes to avoid
+ * wrong validation inside cma.c on receiver side.
+ */
+ msg.__cma_version = 0;
+ msg.__ip_version = 0;
+ msg.magic = cpu_to_le16(RTRS_MAGIC);
+ msg.version = cpu_to_le16(RTRS_PROTO_VER);
+ msg.cid = cpu_to_le16(con->c.cid);
+ msg.cid_num = cpu_to_le16(sess->s.con_num);
+ msg.recon_cnt = cpu_to_le16(sess->s.recon_cnt);
+ uuid_copy(&msg.sess_uuid, &sess->s.uuid);
+ uuid_copy(&msg.paths_uuid, &clt->paths_uuid);
+
+ err = rdma_connect(con->c.cm_id, ¶m);
+ if (err)
+ rtrs_err(clt, "rdma_connect(): %d\n", err);
+
+ return err;
+}
+
+static int rtrs_rdma_conn_established(struct rtrs_clt_con *con,
+ struct rdma_cm_event *ev)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ struct rtrs_clt *clt = sess->clt;
+ const struct rtrs_msg_conn_rsp *msg;
+ u16 version, queue_depth;
+ int errno;
+ u8 len;
+
+ msg = ev->param.conn.private_data;
+ len = ev->param.conn.private_data_len;
+ if (unlikely(len < sizeof(*msg))) {
+ rtrs_err(clt, "Invalid RTRS connection response\n");
+ return -ECONNRESET;
+ }
+ if (unlikely(le16_to_cpu(msg->magic) != RTRS_MAGIC)) {
+ rtrs_err(clt, "Invalid RTRS magic\n");
+ return -ECONNRESET;
+ }
+ version = le16_to_cpu(msg->version);
+ if (unlikely(version >> 8 != RTRS_PROTO_VER_MAJOR)) {
+ rtrs_err(clt, "Unsupported major RTRS version: %d, expected %d\n",
+ version >> 8, RTRS_PROTO_VER_MAJOR);
+ return -ECONNRESET;
+ }
+ errno = le16_to_cpu(msg->errno);
+ if (unlikely(errno)) {
+ rtrs_err(clt, "Invalid RTRS message: errno %d\n",
+ errno);
+ return -ECONNRESET;
+ }
+ if (con->c.cid == 0) {
+ queue_depth = le16_to_cpu(msg->queue_depth);
+
+ if (queue_depth > MAX_SESS_QUEUE_DEPTH) {
+ rtrs_err(clt, "Invalid RTRS message: queue=%d\n",
+ queue_depth);
+ return -ECONNRESET;
+ }
+ if (!sess->rbufs || sess->queue_depth < queue_depth) {
+ kfree(sess->rbufs);
+ sess->rbufs = kcalloc(queue_depth, sizeof(*sess->rbufs),
+ GFP_KERNEL);
+ if (unlikely(!sess->rbufs)) {
+ rtrs_err(clt,
+ "Failed to allocate queue_depth=%d\n",
+ queue_depth);
+ return -ENOMEM;
+ }
+ }
+ sess->queue_depth = queue_depth;
+ sess->max_hdr_size = le32_to_cpu(msg->max_hdr_size);
+ sess->max_io_size = le32_to_cpu(msg->max_io_size);
+ sess->flags = le32_to_cpu(msg->flags);
+ sess->chunk_size = sess->max_io_size + sess->max_hdr_size;
+
+ /*
+ * Global queue depth and IO size is always a minimum.
+ * If while a reconnection server sends us a value a bit
+ * higher - client does not care and uses cached minimum.
+ *
+ * Since we can have several sessions (paths) restablishing
+ * connections in parallel, use lock.
+ */
+ mutex_lock(&clt->paths_mutex);
+ clt->queue_depth = min_not_zero(sess->queue_depth,
+ clt->queue_depth);
+ clt->max_io_size = min_not_zero(sess->max_io_size,
+ clt->max_io_size);
+ mutex_unlock(&clt->paths_mutex);
+
+ /*
+ * Cache the hca_port and hca_name for sysfs
+ */
+ sess->hca_port = con->c.cm_id->port_num;
+ scnprintf(sess->hca_name, sizeof(sess->hca_name),
+ sess->s.dev->ib_dev->name);
+ sess->s.src_addr = con->c.cm_id->route.addr.src_addr;
+ }
+
+ return 0;
+}
+
+static inline void flag_success_on_conn(struct rtrs_clt_con *con)
+{
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+
+ atomic_inc(&sess->connected_cnt);
+ con->cm_err = 1;
+}
+
+static int rtrs_rdma_conn_rejected(struct rtrs_clt_con *con,
+ struct rdma_cm_event *ev)
+{
+ struct rtrs_sess *s = con->c.sess;
+ const struct rtrs_msg_conn_rsp *msg;
+ const char *rej_msg;
+ int status, errno;
+ u8 data_len;
+
+ status = ev->status;
+ rej_msg = rdma_reject_msg(con->c.cm_id, status);
+ msg = rdma_consumer_reject_data(con->c.cm_id, ev, &data_len);
+
+ if (msg && data_len >= sizeof(*msg)) {
+ errno = (int16_t)le16_to_cpu(msg->errno);
+ if (errno == -EBUSY)
+ rtrs_err(s,
+ "Previous session is still exists on the server, please reconnect later\n");
+ else
+ rtrs_err(s,
+ "Connect rejected: status %d (%s), rtrs errno %d\n",
+ status, rej_msg, errno);
+ } else {
+ rtrs_err(s,
+ "Connect rejected but with malformed message: status %d (%s)\n",
+ status, rej_msg);
+ }
+
+ return -ECONNRESET;
+}
+
+static void rtrs_clt_close_conns(struct rtrs_clt_sess *sess, bool wait)
+{
+ if (rtrs_clt_change_state(sess, RTRS_CLT_CLOSING))
+ queue_work(rtrs_wq, &sess->close_work);
+ if (wait)
+ flush_work(&sess->close_work);
+}
+
+static inline void flag_error_on_conn(struct rtrs_clt_con *con, int cm_err)
+{
+ if (con->cm_err == 1) {
+ struct rtrs_clt_sess *sess;
+
+ sess = to_clt_sess(con->c.sess);
+ if (atomic_dec_and_test(&sess->connected_cnt))
+ wake_up(&sess->state_wq);
+ }
+ con->cm_err = cm_err;
+}
+
+static int rtrs_clt_rdma_cm_handler(struct rdma_cm_id *cm_id,
+ struct rdma_cm_event *ev)
+{
+ struct rtrs_clt_con *con = cm_id->context;
+ struct rtrs_sess *s = con->c.sess;
+ struct rtrs_clt_sess *sess = to_clt_sess(s);
+ int cm_err = 0;
+
+ switch (ev->event) {
+ case RDMA_CM_EVENT_ADDR_RESOLVED:
+ cm_err = rtrs_rdma_addr_resolved(con);
+ break;
+ case RDMA_CM_EVENT_ROUTE_RESOLVED:
+ cm_err = rtrs_rdma_route_resolved(con);
+ break;
+ case RDMA_CM_EVENT_ESTABLISHED:
+ con->cm_err = rtrs_rdma_conn_established(con, ev);
+ if (likely(!con->cm_err)) {
+ /*
+ * Report success and wake up. Here we abuse state_wq,
+ * i.e. wake up without state change, but we set cm_err.
+ */
+ flag_success_on_conn(con);
+ wake_up(&sess->state_wq);
+ return 0;
+ }
+ break;
+ case RDMA_CM_EVENT_REJECTED:
+ cm_err = rtrs_rdma_conn_rejected(con, ev);
+ break;
+ case RDMA_CM_EVENT_CONNECT_ERROR:
+ case RDMA_CM_EVENT_UNREACHABLE:
+ rtrs_wrn(s, "CM error event %d\n", ev->event);
+ cm_err = -ECONNRESET;
+ break;
+ case RDMA_CM_EVENT_ADDR_ERROR:
+ case RDMA_CM_EVENT_ROUTE_ERROR:
+ cm_err = -EHOSTUNREACH;
+ break;
+ case RDMA_CM_EVENT_DISCONNECTED:
+ case RDMA_CM_EVENT_ADDR_CHANGE:
+ case RDMA_CM_EVENT_TIMEWAIT_EXIT:
+ cm_err = -ECONNRESET;
+ break;
+ case RDMA_CM_EVENT_DEVICE_REMOVAL:
+ /*
+ * Device removal is a special case. Queue close and return 0.
+ */
+ rtrs_clt_close_conns(sess, false);
+ return 0;
+ default:
+ rtrs_err(s, "Unexpected RDMA CM event (%d)\n", ev->event);
+ cm_err = -ECONNRESET;
+ break;
+ }
+
+ if (cm_err) {
+ /*
+ * cm error makes sense only on connection establishing,
+ * in other cases we rely on normal procedure of reconnecting.
+ */
+ flag_error_on_conn(con, cm_err);
+ rtrs_rdma_error_recovery(con);
+ }
+
+ return 0;
+}
+
+static int create_cm(struct rtrs_clt_con *con)
+{
+ struct rtrs_sess *s = con->c.sess;
+ struct rtrs_clt_sess *sess = to_clt_sess(s);
+ struct rdma_cm_id *cm_id;
+ int err;
+
+ cm_id = rdma_create_id(&init_net, rtrs_clt_rdma_cm_handler, con,
+ sess->s.dst_addr.ss_family == AF_IB ?
+ RDMA_PS_IB : RDMA_PS_TCP, IB_QPT_RC);
+ if (IS_ERR(cm_id)) {
+ err = PTR_ERR(cm_id);
+ rtrs_err(s, "Failed to create CM ID, err: %d\n", err);
+
+ return err;
+ }
+ con->c.cm_id = cm_id;
+ con->cm_err = 0;
+ /* allow the port to be reused */
+ err = rdma_set_reuseaddr(cm_id, 1);
+ if (err != 0) {
+ rtrs_err(s, "Set address reuse failed, err: %d\n", err);
+ goto destroy_cm;
+ }
+ err = rdma_resolve_addr(cm_id, (struct sockaddr *)&sess->s.src_addr,
+ (struct sockaddr *)&sess->s.dst_addr,
+ RTRS_CONNECT_TIMEOUT_MS);
+ if (unlikely(err)) {
+ rtrs_err(s, "Failed to resolve address, err: %d\n", err);
+ goto destroy_cm;
+ }
+ /*
+ * Combine connection status and session events. This is needed
+ * for waiting two possible cases: cm_err has something meaningful
+ * or session state was really changed to error by device removal.
+ */
+ err = wait_event_interruptible_timeout(
+ sess->state_wq,
+ con->cm_err || sess->state != RTRS_CLT_CONNECTING,
+ msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS));
+ if (unlikely(err == 0 || err == -ERESTARTSYS)) {
+ if (err == 0)
+ err = -ETIMEDOUT;
+ /* Timedout or interrupted */
+ goto errr;
+ }
+ if (unlikely(con->cm_err < 0)) {
+ err = con->cm_err;
+ goto errr;
+ }
+ if (unlikely(READ_ONCE(sess->state) != RTRS_CLT_CONNECTING)) {
+ /* Device removal */
+ err = -ECONNABORTED;
+ goto errr;
+ }
+
+ return 0;
+
+errr:
+ stop_cm(con);
+ /* Is safe to call destroy if cq_qp is not inited */
+ destroy_con_cq_qp(con);
+destroy_cm:
+ destroy_cm(con);
+
+ return err;
+}
+
+static void rtrs_clt_sess_up(struct rtrs_clt_sess *sess)
+{
+ struct rtrs_clt *clt = sess->clt;
+ int up;
+
+ /*
+ * We can fire RECONNECTED event only when all paths were
+ * connected on rtrs_clt_open(), then each was disconnected
+ * and the first one connected again. That's why this nasty
+ * game with counter value.
+ */
+
+ mutex_lock(&clt->paths_ev_mutex);
+ up = ++clt->paths_up;
+ /*
+ * Here it is safe to access paths num directly since up counter
+ * is greater than MAX_PATHS_NUM only while rtrs_clt_open() is
+ * in progress, thus paths removals are impossible.
+ */
+ if (up > MAX_PATHS_NUM && up == MAX_PATHS_NUM + clt->paths_num)
+ clt->paths_up = clt->paths_num;
+ else if (up == 1)
+ clt->link_ev(clt->priv, RTRS_CLT_LINK_EV_RECONNECTED);
+ mutex_unlock(&clt->paths_ev_mutex);
+
+ /* Mark session as established */
+ sess->established = true;
+ sess->reconnect_attempts = 0;
+ sess->stats.reconnects.successful_cnt++;
+}
+
+static void rtrs_clt_sess_down(struct rtrs_clt_sess *sess)
+{
+ struct rtrs_clt *clt = sess->clt;
+
+ if (!sess->established)
+ return;
+
+ sess->established = false;
+ mutex_lock(&clt->paths_ev_mutex);
+ WARN_ON(!clt->paths_up);
+ if (--clt->paths_up == 0)
+ clt->link_ev(clt->priv, RTRS_CLT_LINK_EV_DISCONNECTED);
+ mutex_unlock(&clt->paths_ev_mutex);
+}
+
+static void rtrs_clt_stop_and_destroy_conns(struct rtrs_clt_sess *sess)
+{
+ struct rtrs_clt_con *con;
+ unsigned int cid;
+
+ WARN_ON(READ_ONCE(sess->state) == RTRS_CLT_CONNECTED);
+
+ /*
+ * Possible race with rtrs_clt_open(), when DEVICE_REMOVAL comes
+ * exactly in between. Start destroying after it finishes.
+ */
+ mutex_lock(&sess->init_mutex);
+ mutex_unlock(&sess->init_mutex);
+
+ /*
+ * All IO paths must observe !CONNECTED state before we
+ * free everything.
+ */
+ synchronize_rcu();
+
+ rtrs_clt_stop_hb(sess);
+
+ /*
+ * The order it utterly crucial: firstly disconnect and complete all
+ * rdma requests with error (thus set in_use=false for requests),
+ * then fail outstanding requests checking in_use for each, and
+ * eventually notify upper layer about session disconnection.
+ */
+
+ for (cid = 0; cid < sess->s.con_num; cid++) {
+ if (!sess->s.con[cid])
+ break;
+ con = to_clt_con(sess->s.con[cid]);
+ stop_cm(con);
+ }
+ fail_all_outstanding_reqs(sess);
+ free_sess_reqs(sess);
+ rtrs_clt_sess_down(sess);
+
+ /*
+ * Wait for graceful shutdown, namely when peer side invokes
+ * rdma_disconnect(). 'connected_cnt' is decremented only on
+ * CM events, thus if other side had crashed and hb has detected
+ * something is wrong, here we will stuck for exactly timeout ms,
+ * since CM does not fire anything. That is fine, we are not in
+ * hurry.
+ */
+ wait_event_timeout(sess->state_wq, !atomic_read(&sess->connected_cnt),
+ msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS));
+
+ for (cid = 0; cid < sess->s.con_num; cid++) {
+ if (!sess->s.con[cid])
+ break;
+ con = to_clt_con(sess->s.con[cid]);
+ destroy_con_cq_qp(con);
+ destroy_cm(con);
+ destroy_con(con);
+ }
+}
+
+static inline bool xchg_sessions(struct rtrs_clt_sess __rcu **rcu_ppcpu_path,
+ struct rtrs_clt_sess *sess,
+ struct rtrs_clt_sess *next)
+{
+ struct rtrs_clt_sess **ppcpu_path;
+
+ /* Call cmpxchg() without sparse warnings */
+ ppcpu_path = (typeof(ppcpu_path))rcu_ppcpu_path;
+ return (sess == cmpxchg(ppcpu_path, sess, next));
+}
+
+static void rtrs_clt_remove_path_from_arr(struct rtrs_clt_sess *sess)
+{
+ struct rtrs_clt *clt = sess->clt;
+ struct rtrs_clt_sess *next;
+ bool wait_for_grace = false;
+ int cpu;
+
+ mutex_lock(&clt->paths_mutex);
+ list_del_rcu(&sess->s.entry);
+
+ /* Make sure everybody observes path removal. */
+ synchronize_rcu();
+
+ /*
+ * At this point nobody sees @sess in the list, but still we have
+ * dangling pointer @pcpu_path which _can_ point to @sess. Since
+ * nobody can observe @sess in the list, we guarantee that IO path
+ * will not assign @sess to @pcpu_path, i.e. @pcpu_path can be equal
+ * to @sess, but can never again become @sess.
+ */
+
+ /*
+ * Decrement paths number only after grace period, because
+ * caller of do_each_path() must firstly observe list without
+ * path and only then decremented paths number.
+ *
+ * Otherwise there can be the following situation:
+ * o Two paths exist and IO is coming.
+ * o One path is removed:
+ * CPU#0 CPU#1
+ * do_each_path(): rtrs_clt_remove_path_from_arr():
+ * path = get_next_path()
+ * ^^^ list_del_rcu(path)
+ * [!CONNECTED path] clt->paths_num--
+ * ^^^^^^^^^
+ * load clt->paths_num from 2 to 1
+ * ^^^^^^^^^
+ * sees 1
+ *
+ * path is observed as !CONNECTED, but do_each_path() loop
+ * ends, because expression i < clt->paths_num is false.
+ */
+ clt->paths_num--;
+
+ /*
+ * Get @next connection from current @sess which is going to be
+ * removed. If @sess is the last element, then @next is NULL.
+ */
+ next = list_next_or_null_rr_rcu(&clt->paths_list, &sess->s.entry,
+ typeof(*next), s.entry);
+
+ /*
+ * @pcpu paths can still point to the path which is going to be
+ * removed, so change the pointer manually.
+ */
+ for_each_possible_cpu(cpu) {
+ struct rtrs_clt_sess __rcu **ppcpu_path;
+
+ ppcpu_path = per_cpu_ptr(clt->pcpu_path, cpu);
+ if (rcu_dereference(*ppcpu_path) != sess)
+ /*
+ * synchronize_rcu() was called just after deleting
+ * entry from the list, thus IO code path cannot
+ * change pointer back to the pointer which is going
+ * to be removed, we are safe here.
+ */
+ continue;
+
+ /*
+ * We race with IO code path, which also changes pointer,
+ * thus we have to be careful not to overwrite it.
+ */
+ if (xchg_sessions(ppcpu_path, sess, next))
+ /*
+ * @ppcpu_path was successfully replaced with @next,
+ * that means that someone could also pick up the
+ * @sess and dereferencing it right now, so wait for
+ * a grace period is required.
+ */
+ wait_for_grace = true;
+ }
+ if (wait_for_grace)
+ synchronize_rcu();
+
+ mutex_unlock(&clt->paths_mutex);
+}
+
+static void rtrs_clt_add_path_to_arr(struct rtrs_clt_sess *sess,
+ struct rtrs_addr *addr)
+{
+ struct rtrs_clt *clt = sess->clt;
+
+ mutex_lock(&clt->paths_mutex);
+ clt->paths_num++;
+
+ /*
+ * Firstly increase paths_num, wait for GP and then
+ * add path to the list. Why? Since we add path with
+ * !CONNECTED state explanation is similar to what has
+ * been written in rtrs_clt_remove_path_from_arr().
+ */
+ synchronize_rcu();
+
+ list_add_tail_rcu(&sess->s.entry, &clt->paths_list);
+ mutex_unlock(&clt->paths_mutex);
+}
+
+static void rtrs_clt_close_work(struct work_struct *work)
+{
+ struct rtrs_clt_sess *sess;
+
+ sess = container_of(work, struct rtrs_clt_sess, close_work);
+
+ cancel_delayed_work_sync(&sess->reconnect_dwork);
+ rtrs_clt_stop_and_destroy_conns(sess);
+ /*
+ * Sounds stupid, huh? No, it is not. Consider this sequence:
+ *
+ * #CPU0 #CPU1
+ * 1. CONNECTED->RECONNECTING
+ * 2. RECONNECTING->CLOSING
+ * 3. queue_work(&reconnect_dwork)
+ * 4. queue_work(&close_work);
+ * 5. reconnect_work(); close_work();
+ *
+ * To avoid that case do cancel twice: before and after.
+ */
+ cancel_delayed_work_sync(&sess->reconnect_dwork);
+ rtrs_clt_change_state(sess, RTRS_CLT_CLOSED);
+}
+
+static int init_conns(struct rtrs_clt_sess *sess)
+{
+ unsigned int cid;
+ int err;
+
+ /*
+ * On every new session connections increase reconnect counter
+ * to avoid clashes with previous sessions not yet closed
+ * sessions on a server side.
+ */
+ sess->s.recon_cnt++;
+
+ /* Establish all RDMA connections */
+ for (cid = 0; cid < sess->s.con_num; cid++) {
+ err = create_con(sess, cid);
+ if (unlikely(err))
+ goto destroy;
+
+ err = create_cm(to_clt_con(sess->s.con[cid]));
+ if (unlikely(err)) {
+ destroy_con(to_clt_con(sess->s.con[cid]));
+ goto destroy;
+ }
+ }
+ err = alloc_sess_reqs(sess);
+ if (unlikely(err))
+ goto destroy;
+
+ rtrs_clt_start_hb(sess);
+
+ return 0;
+
+destroy:
+ while (cid--) {
+ struct rtrs_clt_con *con = to_clt_con(sess->s.con[cid]);
+
+ stop_cm(con);
+ destroy_con_cq_qp(con);
+ destroy_cm(con);
+ destroy_con(con);
+ }
+ /*
+ * If we've never taken async path and got an error, say,
+ * doing rdma_resolve_addr(), switch to CONNECTION_ERR state
+ * manually to keep reconnecting.
+ */
+ rtrs_clt_change_state(sess, RTRS_CLT_CONNECTING_ERR);
+
+ return err;
+}
+
+static void rtrs_clt_info_req_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+ struct rtrs_clt_con *con = cq->cq_context;
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ struct rtrs_iu *iu;
+
+ iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
+ rtrs_iu_free(iu, DMA_TO_DEVICE, sess->s.dev->ib_dev, 1);
+
+ if (unlikely(wc->status != IB_WC_SUCCESS)) {
+ rtrs_err(sess->clt, "Sess info request send failed: %s\n",
+ ib_wc_status_msg(wc->status));
+ rtrs_clt_change_state(sess, RTRS_CLT_CONNECTING_ERR);
+ return;
+ }
+
+ rtrs_clt_update_wc_stats(con);
+}
+
+static int process_info_rsp(struct rtrs_clt_sess *sess,
+ const struct rtrs_msg_info_rsp *msg)
+{
+ unsigned int sg_cnt, total_len;
+ int i, sgi;
+
+ sg_cnt = le16_to_cpu(msg->sg_cnt);
+ if (unlikely(!sg_cnt))
+ return -EINVAL;
+ /*
+ * Check if IB immediate data size is enough to hold the mem_id and
+ * the offset inside the memory chunk.
+ */
+ if (unlikely((ilog2(sg_cnt - 1) + 1) +
+ (ilog2(sess->chunk_size - 1) + 1) >
+ MAX_IMM_PAYL_BITS)) {
+ rtrs_err(sess->clt,
+ "RDMA immediate size (%db) not enough to encode %d buffers of size %dB\n",
+ MAX_IMM_PAYL_BITS, sg_cnt, sess->chunk_size);
+ return -EINVAL;
+ }
+ if (unlikely(!sg_cnt || (sess->queue_depth % sg_cnt))) {
+ rtrs_err(sess->clt, "Incorrect sg_cnt %d, is not multiple\n",
+ sg_cnt);
+ return -EINVAL;
+ }
+ total_len = 0;
+ for (sgi = 0, i = 0; sgi < sg_cnt && i < sess->queue_depth; sgi++) {
+ const struct rtrs_sg_desc *desc = &msg->desc[sgi];
+ u32 len, rkey;
+ u64 addr;
+
+ addr = le64_to_cpu(desc->addr);
+ rkey = le32_to_cpu(desc->key);
+ len = le32_to_cpu(desc->len);
+
+ total_len += len;
+
+ if (unlikely(!len || (len % sess->chunk_size))) {
+ rtrs_err(sess->clt, "Incorrect [%d].len %d\n", sgi,
+ len);
+ return -EINVAL;
+ }
+ for ( ; len && i < sess->queue_depth; i++) {
+ sess->rbufs[i].addr = addr;
+ sess->rbufs[i].rkey = rkey;
+
+ len -= sess->chunk_size;
+ addr += sess->chunk_size;
+ }
+ }
+ /* Sanity check */
+ if (unlikely(sgi != sg_cnt || i != sess->queue_depth)) {
+ rtrs_err(sess->clt, "Incorrect sg vector, not fully mapped\n");
+ return -EINVAL;
+ }
+ if (unlikely(total_len != sess->chunk_size * sess->queue_depth)) {
+ rtrs_err(sess->clt, "Incorrect total_len %d\n", total_len);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void rtrs_clt_info_rsp_done(struct ib_cq *cq, struct ib_wc *wc)
+{
+ struct rtrs_clt_con *con = cq->cq_context;
+ struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
+ struct rtrs_msg_info_rsp *msg;
+ enum rtrs_clt_state state;
+ struct rtrs_iu *iu;
+ size_t rx_sz;
+ int err;
+
+ state = RTRS_CLT_CONNECTING_ERR;
+
+ WARN_ON(con->c.cid);
+ iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe);
+ if (unlikely(wc->status != IB_WC_SUCCESS)) {
+ rtrs_err(sess->clt, "Sess info response recv failed: %s\n",
+ ib_wc_status_msg(wc->status));
+ goto out;
+ }
+ WARN_ON(wc->opcode != IB_WC_RECV);
+
+ if (unlikely(wc->byte_len < sizeof(*msg))) {
+ rtrs_err(sess->clt, "Sess info response is malformed: size %d\n",
+ wc->byte_len);
+ goto out;
+ }
+ ib_dma_sync_single_for_cpu(sess->s.dev->ib_dev, iu->dma_addr,
+ iu->size, DMA_FROM_DEVICE);
+ msg = iu->buf;
+ if (unlikely(le16_to_cpu(msg->type) != RTRS_MSG_INFO_RSP)) {
+ rtrs_err(sess->clt, "Sess info response is malformed: type %d\n",
+ le16_to_cpu(msg->type));
+ goto out;
+ }
+ rx_sz = sizeof(*msg);
+ rx_sz += sizeof(msg->desc[0]) * le16_to_cpu(msg->sg_cnt);
+ if (unlikely(wc->byte_len < rx_sz)) {
+ rtrs_err(sess->clt, "Sess info response is malformed: size %d\n",
+ wc->byte_len);
+ goto out;
+ }
+ err = process_info_rsp(sess, msg);
+ if (unlikely(err))
+ goto out;
+
+ err = post_recv_sess(sess);
+ if (unlikely(err))
+ goto out;
+
+ state = RTRS_CLT_CONNECTED;
+
+out:
+ rtrs_clt_update_wc_stats(con);
+ rtrs_iu_free(iu, DMA_FROM_DEVICE, sess->s.dev->ib_dev, 1);
+ rtrs_clt_change_state(sess, state);
+}
+
+static int rtrs_send_sess_info(struct rtrs_clt_sess *sess)
+{
+ struct rtrs_clt_con *usr_con = to_clt_con(sess->s.con[0]);
+ struct rtrs_msg_info_req *msg;
+ struct rtrs_iu *tx_iu, *rx_iu;
+ size_t rx_sz;
+ int err;
+
+ rx_sz = sizeof(struct rtrs_msg_info_rsp);
+ rx_sz += sizeof(u64) * MAX_SESS_QUEUE_DEPTH;
+
+ tx_iu = rtrs_iu_alloc(1, sizeof(struct rtrs_msg_info_req), GFP_KERNEL,
+ sess->s.dev->ib_dev, DMA_TO_DEVICE,
+ rtrs_clt_info_req_done);
+ rx_iu = rtrs_iu_alloc(1, rx_sz, GFP_KERNEL, sess->s.dev->ib_dev,
+ DMA_FROM_DEVICE, rtrs_clt_info_rsp_done);
+ if (unlikely(!tx_iu || !rx_iu)) {
+ rtrs_err(sess->clt, "rtrs_iu_alloc(): no memory\n");
+ err = -ENOMEM;
+ goto out;
+ }
+ /* Prepare for getting info response */
+ err = rtrs_iu_post_recv(&usr_con->c, rx_iu);
+ if (unlikely(err)) {
+ rtrs_err(sess->clt, "rtrs_iu_post_recv(), err: %d\n", err);
+ goto out;
+ }
+ rx_iu = NULL;
+
+ msg = tx_iu->buf;
+ msg->type = cpu_to_le16(RTRS_MSG_INFO_REQ);
+ memcpy(msg->sessname, sess->s.sessname, sizeof(msg->sessname));
+
+ ib_dma_sync_single_for_device(sess->s.dev->ib_dev, tx_iu->dma_addr,
+ tx_iu->size, DMA_TO_DEVICE);
+
+ /* Send info request */
+ err = rtrs_iu_post_send(&usr_con->c, tx_iu, sizeof(*msg), NULL);
+ if (unlikely(err)) {
+ rtrs_err(sess->clt, "rtrs_iu_post_send(), err: %d\n", err);
+ goto out;
+ }
+ tx_iu = NULL;
+
+ /* Wait for state change */
+ wait_event_interruptible_timeout(sess->state_wq,
+ sess->state != RTRS_CLT_CONNECTING,
+ msecs_to_jiffies(
+ RTRS_CONNECT_TIMEOUT_MS));
+ if (unlikely(READ_ONCE(sess->state) != RTRS_CLT_CONNECTED)) {
+ if (READ_ONCE(sess->state) == RTRS_CLT_CONNECTING_ERR)
+ err = -ECONNRESET;
+ else
+ err = -ETIMEDOUT;
+ goto out;
+ }
+
+out:
+ if (tx_iu)
+ rtrs_iu_free(tx_iu, DMA_TO_DEVICE, sess->s.dev->ib_dev, 1);
+ if (rx_iu)
+ rtrs_iu_free(rx_iu, DMA_FROM_DEVICE, sess->s.dev->ib_dev, 1);
+ if (unlikely(err))
+ /* If we've never taken async path because of malloc problems */
+ rtrs_clt_change_state(sess, RTRS_CLT_CONNECTING_ERR);
+
+ return err;
+}
+
+/**
+ * init_sess() - establishes all session connections and does handshake
+ *
+ * In case of error full close or reconnect procedure should be taken,
+ * because reconnect or close async works can be started.
+ */
+static int init_sess(struct rtrs_clt_sess *sess)
+{
+ int err;
+
+ mutex_lock(&sess->init_mutex);
+ err = init_conns(sess);
+ if (unlikely(err)) {
+ rtrs_err(sess->clt, "init_conns(), err: %d\n", err);
+ goto out;
+ }
+ err = rtrs_send_sess_info(sess);
+ if (unlikely(err)) {
+ rtrs_err(sess->clt, "rtrs_send_sess_info(), err: %d\n", err);
+ goto out;
+ }
+ rtrs_clt_sess_up(sess);
+out:
+ mutex_unlock(&sess->init_mutex);
+
+ return err;
+}
+
+static void rtrs_clt_reconnect_work(struct work_struct *work)
+{
+ struct rtrs_clt_sess *sess;
+ struct rtrs_clt *clt;
+ unsigned int delay_ms;
+ int err;
+
+ sess = container_of(to_delayed_work(work), struct rtrs_clt_sess,
+ reconnect_dwork);
+ clt = sess->clt;
+
+ if (READ_ONCE(sess->state) == RTRS_CLT_CLOSING)
+ /* User requested closing */
+ return;
+
+ if (sess->reconnect_attempts >= clt->max_reconnect_attempts) {
+ /* Close a session completely if max attempts is reached */
+ rtrs_clt_close_conns(sess, false);
+ return;
+ }
+ sess->reconnect_attempts++;
+
+ /* Stop everything */
+ rtrs_clt_stop_and_destroy_conns(sess);
+ rtrs_clt_change_state(sess, RTRS_CLT_CONNECTING);
+
+ err = init_sess(sess);
+ if (unlikely(err))
+ goto reconnect_again;
+
+ return;
+
+reconnect_again:
+ if (rtrs_clt_change_state(sess, RTRS_CLT_RECONNECTING)) {
+ sess->stats.reconnects.fail_cnt++;
+ delay_ms = clt->reconnect_delay_sec * 1000;
+ queue_delayed_work(rtrs_wq, &sess->reconnect_dwork,
+ msecs_to_jiffies(delay_ms));
+ }
+}
+
+static void rtrs_clt_dev_release(struct device *dev)
+{
+ struct rtrs_clt *clt = container_of(dev, struct rtrs_clt, dev);
+
+ kfree(clt);
+}
+
+static struct rtrs_clt *alloc_clt(const char *sessname, size_t paths_num,
+ short port, size_t pdu_sz,
+ void *priv, link_clt_ev_fn *link_ev,
+ unsigned int max_segments,
+ unsigned int reconnect_delay_sec,
+ unsigned int max_reconnect_attempts)
+{
+ struct rtrs_clt *clt;
+ int err;
+
+ if (unlikely(!paths_num || paths_num > MAX_PATHS_NUM))
+ return ERR_PTR(-EINVAL);
+
+ if (unlikely(strlen(sessname) >= sizeof(clt->sessname)))
+ return ERR_PTR(-EINVAL);
+
+ clt = kzalloc(sizeof(*clt), GFP_KERNEL);
+ if (unlikely(!clt))
+ return ERR_PTR(-ENOMEM);
+
+ clt->pcpu_path = alloc_percpu(typeof(*clt->pcpu_path));
+ if (unlikely(!clt->pcpu_path)) {
+ kfree(clt);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ uuid_gen(&clt->paths_uuid);
+ INIT_LIST_HEAD_RCU(&clt->paths_list);
+ clt->paths_num = paths_num;
+ clt->paths_up = MAX_PATHS_NUM;
+ clt->port = port;
+ clt->pdu_sz = pdu_sz;
+ clt->max_segments = max_segments;
+ clt->reconnect_delay_sec = reconnect_delay_sec;
+ clt->max_reconnect_attempts = max_reconnect_attempts;
+ clt->priv = priv;
+ clt->link_ev = link_ev;
+ clt->mp_policy = MP_POLICY_MIN_INFLIGHT;
+ strlcpy(clt->sessname, sessname, sizeof(clt->sessname));
+ init_waitqueue_head(&clt->permits_wait);
+ mutex_init(&clt->paths_ev_mutex);
+ mutex_init(&clt->paths_mutex);
+
+ clt->dev.class = rtrs_dev_class;
+ clt->dev.release = rtrs_clt_dev_release;
+ dev_set_name(&clt->dev, "%s", sessname);
+
+ err = device_register(&clt->dev);
+ if (unlikely(err))
+ goto percpu_free;
+
+ err = rtrs_clt_create_sysfs_root_folders(clt);
+ if (unlikely(err))
+ goto dev_unregister;
+
+ return clt;
+
+dev_unregister:
+ device_unregister(&clt->dev);
+percpu_free:
+ free_percpu(clt->pcpu_path);
+ kfree(clt);
+ return ERR_PTR(err);
+}
+
+static void wait_for_inflight_permits(struct rtrs_clt *clt)
+{
+ if (clt->permits_map) {
+ size_t sz = clt->queue_depth;
+
+ wait_event(clt->permits_wait,
+ find_first_bit(clt->permits_map, sz) >= sz);
+ }
+}
+
+static void free_clt(struct rtrs_clt *clt)
+{
+ rtrs_clt_destroy_sysfs_root_folders(clt);
+ wait_for_inflight_permits(clt);
+ free_permits(clt);
+ free_percpu(clt->pcpu_path);
+ /* release callback will free clt in last put */
+ device_unregister(&clt->dev);
+}
+
+struct rtrs_clt *rtrs_clt_open(void *priv, link_clt_ev_fn *link_ev,
+ const char *sessname,
+ const struct rtrs_addr *paths,
+ size_t paths_num,
+ short port,
+ size_t pdu_sz, u8 reconnect_delay_sec,
+ u16 max_segments,
+ s16 max_reconnect_attempts)
+{
+ struct rtrs_clt_sess *sess, *tmp;
+ struct rtrs_clt *clt;
+ int err, i;
+
+ clt = alloc_clt(sessname, paths_num, port, pdu_sz, priv, link_ev,
+ max_segments, reconnect_delay_sec,
+ max_reconnect_attempts);
+ if (IS_ERR(clt)) {
+ err = PTR_ERR(clt);
+ goto out;
+ }
+ for (i = 0; i < paths_num; i++) {
+ struct rtrs_clt_sess *sess;
+
+ sess = alloc_sess(clt, &paths[i], nr_cons_per_session,
+ max_segments);
+ if (IS_ERR(sess)) {
+ err = PTR_ERR(sess);
+ rtrs_err(clt, "alloc_sess(), err: %d\n", err);
+ goto close_all_sess;
+ }
+ list_add_tail_rcu(&sess->s.entry, &clt->paths_list);
+
+ err = init_sess(sess);
+ if (unlikely(err))
+ goto close_all_sess;
+
+ err = rtrs_clt_create_sess_files(sess);
+ if (unlikely(err))
+ goto close_all_sess;
+ }
+ err = alloc_permits(clt);
+ if (unlikely(err)) {
+ rtrs_err(clt, "alloc_permits(), err: %d\n", err);
+ goto close_all_sess;
+ }
+ err = rtrs_clt_create_sysfs_root_files(clt);
+ if (unlikely(err))
+ goto close_all_sess;
+
+ /*
+ * There is a race if someone decides to completely remove just
+ * newly created path using sysfs entry. To avoid the race we
+ * use simple 'opened' flag, see rtrs_clt_remove_path_from_sysfs().
+ */
+ clt->opened = true;
+
+ /* Do not let module be unloaded if client is alive */
+ __module_get(THIS_MODULE);
+
+ return clt;
+
+close_all_sess:
+ list_for_each_entry_safe(sess, tmp, &clt->paths_list, s.entry) {
+ rtrs_clt_destroy_sess_files(sess, NULL);
+ rtrs_clt_close_conns(sess, true);
+ free_sess(sess);
+ }
+ free_clt(clt);
+
+out:
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL(rtrs_clt_open);
+
+void rtrs_clt_close(struct rtrs_clt *clt)
+{
+ struct rtrs_clt_sess *sess, *tmp;
+
+ /* Firstly forbid sysfs access */
+ rtrs_clt_destroy_sysfs_root_files(clt);
+ rtrs_clt_destroy_sysfs_root_folders(clt);
+
+ /* Now it is safe to iterate over all paths without locks */
+ list_for_each_entry_safe(sess, tmp, &clt->paths_list, s.entry) {
+ rtrs_clt_destroy_sess_files(sess, NULL);
+ rtrs_clt_close_conns(sess, true);
+ free_sess(sess);
+ }
+ free_clt(clt);
+ module_put(THIS_MODULE);
+}
+EXPORT_SYMBOL(rtrs_clt_close);
+
+int rtrs_clt_reconnect_from_sysfs(struct rtrs_clt_sess *sess)
+{
+ enum rtrs_clt_state old_state;
+ int err = -EBUSY;
+ bool changed;
+
+ changed = rtrs_clt_change_state_get_old(sess, RTRS_CLT_RECONNECTING,
+ &old_state);
+ if (changed) {
+ sess->reconnect_attempts = 0;
+ queue_delayed_work(rtrs_wq, &sess->reconnect_dwork, 0);
+ }
+ if (changed || old_state == RTRS_CLT_RECONNECTING) {
+ /*
+ * flush_delayed_work() queues pending work for immediate
+ * execution, so do the flush if we have queued something
+ * right now or work is pending.
+ */
+ flush_delayed_work(&sess->reconnect_dwork);
+ err = (READ_ONCE(sess->state) ==
+ RTRS_CLT_CONNECTED ? 0 : -ENOTCONN);
+ }
+
+ return err;
+}
+
+int rtrs_clt_disconnect_from_sysfs(struct rtrs_clt_sess *sess)
+{
+ rtrs_clt_close_conns(sess, true);
+
+ return 0;
+}
+
+int rtrs_clt_remove_path_from_sysfs(struct rtrs_clt_sess *sess,
+ const struct attribute *sysfs_self)
+{
+ struct rtrs_clt *clt = sess->clt;
+ enum rtrs_clt_state old_state;
+ bool changed;
+
+ /*
+ * That can happen only when userspace tries to remove path
+ * very early, when rtrs_clt_open() is not yet finished.
+ */
+ if (unlikely(!clt->opened))
+ return -EBUSY;
+
+ /*
+ * Continue stopping path till state was changed to DEAD or
+ * state was observed as DEAD:
+ * 1. State was changed to DEAD - we were fast and nobody
+ * invoked rtrs_clt_reconnect(), which can again start
+ * reconnecting.
+ * 2. State was observed as DEAD - we have someone in parallel
+ * removing the path.
+ */
+ do {
+ rtrs_clt_close_conns(sess, true);
+ } while (!(changed = rtrs_clt_change_state_get_old(sess,
+ RTRS_CLT_DEAD,
+ &old_state)) &&
+ old_state != RTRS_CLT_DEAD);
+
+ /*
+ * If state was successfully changed to DEAD, commit suicide.
+ */
+ if (likely(changed)) {
+ rtrs_clt_destroy_sess_files(sess, sysfs_self);
+ rtrs_clt_remove_path_from_arr(sess);
+ free_sess(sess);
+ }
+
+ return 0;
+}
+
+void rtrs_clt_set_max_reconnect_attempts(struct rtrs_clt *clt, int value)
+{
+ clt->max_reconnect_attempts = (unsigned int)value;
+}
+
+int rtrs_clt_get_max_reconnect_attempts(const struct rtrs_clt *clt)
+{
+ return (int)clt->max_reconnect_attempts;
+}
+
+int rtrs_clt_request(int dir, rtrs_conf_fn *conf, struct rtrs_clt *clt,
+ struct rtrs_permit *permit, void *priv,
+ const struct kvec *vec, size_t nr, size_t data_len,
+ struct scatterlist *sg, unsigned int sg_cnt)
+{
+ struct rtrs_clt_io_req *req;
+ struct rtrs_clt_sess *sess;
+
+ enum dma_data_direction dma_dir;
+ int err = -ECONNABORTED, i;
+ size_t usr_len, hdr_len;
+ struct path_it it;
+
+ /* Get kvec length */
+ for (i = 0, usr_len = 0; i < nr; i++)
+ usr_len += vec[i].iov_len;
+
+ if (dir == READ) {
+ hdr_len = sizeof(struct rtrs_msg_rdma_read) +
+ sg_cnt * sizeof(struct rtrs_sg_desc);
+ dma_dir = DMA_FROM_DEVICE;
+ } else {
+ hdr_len = sizeof(struct rtrs_msg_rdma_write);
+ dma_dir = DMA_TO_DEVICE;
+ }
+
+ do_each_path(sess, clt, &it) {
+ if (unlikely(READ_ONCE(sess->state) != RTRS_CLT_CONNECTED))
+ continue;
+
+ if (unlikely(usr_len + hdr_len > sess->max_hdr_size)) {
+ rtrs_wrn_rl(sess->clt,
+ "%s request failed, user message size is %zu and header length %zu, but max size is %u\n",
+ dir == READ ? "Read" : "Write",
+ usr_len, hdr_len, sess->max_hdr_size);
+ err = -EMSGSIZE;
+ break;
+ }
+ req = rtrs_clt_get_req(sess, conf, permit, priv, vec, usr_len,
+ sg, sg_cnt, data_len, dma_dir);
+ if (dir == READ)
+ err = rtrs_clt_read_req(req);
+ else
+ err = rtrs_clt_write_req(req);
+ if (unlikely(err)) {
+ req->in_use = false;
+ continue;
+ }
+ /* Success path */
+ break;
+ } while_each_path(&it);
+
+ return err;
+}
+EXPORT_SYMBOL(rtrs_clt_request);
+
+int rtrs_clt_query(struct rtrs_clt *clt, struct rtrs_attrs *attr)
+{
+ if (unlikely(!rtrs_clt_is_connected(clt)))
+ return -ECOMM;
+
+ attr->queue_depth = clt->queue_depth;
+ attr->max_io_size = clt->max_io_size;
+ attr->sess_kobj = &clt->dev.kobj;
+ strlcpy(attr->sessname, clt->sessname, sizeof(attr->sessname));
+
+ return 0;
+}
+EXPORT_SYMBOL(rtrs_clt_query);
+
+int rtrs_clt_create_path_from_sysfs(struct rtrs_clt *clt,
+ struct rtrs_addr *addr)
+{
+ struct rtrs_clt_sess *sess;
+ int err;
+
+ sess = alloc_sess(clt, addr, nr_cons_per_session, clt->max_segments);
+ if (IS_ERR(sess))
+ return PTR_ERR(sess);
+
+ /*
+ * It is totally safe to add path in CONNECTING state: coming
+ * IO will never grab it. Also it is very important to add
+ * path before init, since init fires LINK_CONNECTED event.
+ */
+ rtrs_clt_add_path_to_arr(sess, addr);
+
+ err = init_sess(sess);
+ if (unlikely(err))
+ goto close_sess;
+
+ err = rtrs_clt_create_sess_files(sess);
+ if (unlikely(err))
+ goto close_sess;
+
+ return 0;
+
+close_sess:
+ rtrs_clt_remove_path_from_arr(sess);
+ rtrs_clt_close_conns(sess, true);
+ free_sess(sess);
+
+ return err;
+}
+
+static int check_module_params(void)
+{
+ if (nr_cons_per_session == 0)
+ nr_cons_per_session = min_t(unsigned int, nr_cpu_ids, U16_MAX);
+
+ return 0;
+}
+
+static int rtrs_clt_ib_dev_init(struct rtrs_ib_dev *dev)
+{
+ if (!(dev->ib_dev->attrs.device_cap_flags &
+ IB_DEVICE_MEM_MGT_EXTENSIONS)) {
+ pr_err("Memory registrations not supported.\n");
+ return -ENOTSUPP;
+ }
+
+ return 0;
+}
+
+static const struct rtrs_ib_dev_pool_ops dev_pool_ops = {
+ .init = rtrs_clt_ib_dev_init
+};
+
+static int __init rtrs_client_init(void)
+{
+ int err;
+
+ pr_info("Loading module %s, proto %s: (retry_cnt: %d, noreg_cnt: %d)\n",
+ KBUILD_MODNAME, RTRS_PROTO_VER_STRING,
+ retry_cnt, noreg_cnt);
+
+ rtrs_ib_dev_pool_init(noreg_cnt ? IB_PD_UNSAFE_GLOBAL_RKEY : 0,
+ &dev_pool);
+
+ err = check_module_params();
+ if (unlikely(err)) {
+ pr_err("Failed to load module, invalid module parameters, err: %d\n",
+ err);
+ return err;
+ }
+ rtrs_dev_class = class_create(THIS_MODULE, "rtrs-client");
+ if (IS_ERR(rtrs_dev_class)) {
+ pr_err("Failed to create rtrs-client dev class\n");
+ return PTR_ERR(rtrs_dev_class);
+ }
+ rtrs_wq = alloc_workqueue("rtrs_client_wq", WQ_MEM_RECLAIM, 0);
+ if (unlikely(!rtrs_wq)) {
+ pr_err("Failed to load module, alloc rtrs_client_wq failed\n");
+ class_destroy(rtrs_dev_class);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void __exit rtrs_client_exit(void)
+{
+ destroy_workqueue(rtrs_wq);
+ class_destroy(rtrs_dev_class);
+ rtrs_ib_dev_pool_deinit(&dev_pool);
+}
+
+module_init(rtrs_client_init);
+module_exit(rtrs_client_exit);