diff options
Diffstat (limited to 'drivers/infiniband/ulp/rtrs/rtrs-clt.c')
| -rw-r--r-- | drivers/infiniband/ulp/rtrs/rtrs-clt.c | 3190 |
1 files changed, 3190 insertions, 0 deletions
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c new file mode 100644 index 000000000000..8546b8816524 --- /dev/null +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c @@ -0,0 +1,3190 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * RDMA 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 - 2020 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/random.h> + +#include "rtrs-clt.h" +#include "rtrs-log.h" +#include "rtrs-clt-trace.h" + +#define RTRS_CONNECT_TIMEOUT_MS 30000 +/* + * Wait a bit before trying to reconnect after a failure + * in order to give server time to finish clean up which + * leads to "false positives" failed reconnect attempts + */ +#define RTRS_RECONNECT_BACKOFF 1000 +/* + * Wait for additional random time between 0 and 8 seconds + * before starting to reconnect to avoid clients reconnecting + * all at once in case of a major network outage + */ +#define RTRS_RECONNECT_SEED 8 + +#define FIRST_CONN 0x01 +/* limit to 128 * 4k = 512k max IO */ +#define RTRS_MAX_SEGMENTS 128 + +MODULE_DESCRIPTION("RDMA Transport Client"); +MODULE_LICENSE("GPL"); + +static const struct rtrs_rdma_dev_pd_ops dev_pd_ops; +static struct rtrs_rdma_dev_pd dev_pd = { + .ops = &dev_pd_ops +}; + +static struct workqueue_struct *rtrs_wq; +static struct class *rtrs_clt_dev_class; + +static inline bool rtrs_clt_is_connected(const struct rtrs_clt_sess *clt) +{ + struct rtrs_clt_path *clt_path; + bool connected = false; + + rcu_read_lock(); + list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) + if (READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTED) { + connected = true; + break; + } + rcu_read_unlock(); + + return connected; +} + +static struct rtrs_permit * +__rtrs_get_permit(struct rtrs_clt_sess *clt, enum rtrs_clt_con_type con_type) +{ + size_t max_depth = clt->queue_depth; + struct rtrs_permit *permit; + int bit; + + /* + * Adapted from null_blk get_tag(). Callers from different cpus may + * grab the same bit, since find_first_zero_bit is not atomic. + * But then the test_and_set_bit_lock will fail for all the + * callers but one, so that they will loop again. + * This way an explicit spinlock is not required. + */ + do { + bit = find_first_zero_bit(clt->permits_map, max_depth); + if (bit >= max_depth) + return NULL; + } while (test_and_set_bit_lock(bit, clt->permits_map)); + + permit = get_permit(clt, bit); + WARN_ON(permit->mem_id != bit); + permit->cpu_id = raw_smp_processor_id(); + permit->con_type = con_type; + + return permit; +} + +static inline void __rtrs_put_permit(struct rtrs_clt_sess *clt, + struct rtrs_permit *permit) +{ + clear_bit_unlock(permit->mem_id, clt->permits_map); +} + +/** + * rtrs_clt_get_permit() - allocates permit for future RDMA operation + * @clt: Current session + * @con_type: Type of connection to use with the permit + * @can_wait: Wait type + * + * Description: + * Allocates permit for the following RDMA operation. Permit is used + * to preallocate all resources and to propagate memory pressure + * up earlier. + * + * Context: + * Can sleep if @wait == RTRS_PERMIT_WAIT + */ +struct rtrs_permit *rtrs_clt_get_permit(struct rtrs_clt_sess *clt, + enum rtrs_clt_con_type con_type, + enum wait_type can_wait) +{ + struct rtrs_permit *permit; + DEFINE_WAIT(wait); + + permit = __rtrs_get_permit(clt, con_type); + if (permit || !can_wait) + return permit; + + do { + prepare_to_wait(&clt->permits_wait, &wait, + TASK_UNINTERRUPTIBLE); + permit = __rtrs_get_permit(clt, con_type); + if (permit) + break; + + io_schedule(); + } while (1); + + finish_wait(&clt->permits_wait, &wait); + + return permit; +} +EXPORT_SYMBOL(rtrs_clt_get_permit); + +/** + * rtrs_clt_put_permit() - puts allocated permit + * @clt: Current session + * @permit: Permit to be freed + * + * Context: + * Does not matter + */ +void rtrs_clt_put_permit(struct rtrs_clt_sess *clt, + struct rtrs_permit *permit) +{ + if (WARN_ON(!test_bit(permit->mem_id, clt->permits_map))) + return; + + __rtrs_put_permit(clt, permit); + + /* + * rtrs_clt_get_permit() adds itself to the &clt->permits_wait list + * before calling schedule(). So if rtrs_clt_get_permit() is sleeping + * it must have added itself to &clt->permits_wait before + * __rtrs_put_permit() finished. + * Hence it is safe to guard wake_up() with a waitqueue_active() test. + */ + if (waitqueue_active(&clt->permits_wait)) + wake_up(&clt->permits_wait); +} +EXPORT_SYMBOL(rtrs_clt_put_permit); + +/** + * rtrs_permit_to_clt_con() - returns RDMA connection pointer by the permit + * @clt_path: client path pointer + * @permit: permit for the allocation of the RDMA buffer + * 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_path *clt_path, + struct rtrs_permit *permit) +{ + int id = 0; + + if (permit->con_type == RTRS_IO_CON) + id = (permit->cpu_id % (clt_path->s.irq_con_num - 1)) + 1; + + return to_clt_con(clt_path->s.con[id]); +} + +/** + * rtrs_clt_change_state() - change the session state through session state + * machine. + * + * @clt_path: client path to change the state of. + * @new_state: state to change to. + * + * returns true if sess's state is changed to new state, otherwise return false. + * + * Locks: + * state_wq lock must be hold. + */ +static bool rtrs_clt_change_state(struct rtrs_clt_path *clt_path, + enum rtrs_clt_state new_state) +{ + enum rtrs_clt_state old_state; + bool changed = false; + + lockdep_assert_held(&clt_path->state_wq.lock); + + old_state = clt_path->state; + switch (new_state) { + case RTRS_CLT_CONNECTING: + switch (old_state) { + case RTRS_CLT_RECONNECTING: + changed = true; + fallthrough; + 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; + fallthrough; + default: + break; + } + break; + case RTRS_CLT_CONNECTED: + switch (old_state) { + case RTRS_CLT_CONNECTING: + changed = true; + fallthrough; + default: + break; + } + break; + case RTRS_CLT_CONNECTING_ERR: + switch (old_state) { + case RTRS_CLT_CONNECTING: + changed = true; + fallthrough; + 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; + fallthrough; + default: + break; + } + break; + case RTRS_CLT_CLOSED: + switch (old_state) { + case RTRS_CLT_CLOSING: + changed = true; + fallthrough; + default: + break; + } + break; + case RTRS_CLT_DEAD: + switch (old_state) { + case RTRS_CLT_CLOSED: + changed = true; + fallthrough; + default: + break; + } + break; + default: + break; + } + if (changed) { + clt_path->state = new_state; + wake_up_locked(&clt_path->state_wq); + } + + return changed; +} + +static bool rtrs_clt_change_state_from_to(struct rtrs_clt_path *clt_path, + enum rtrs_clt_state old_state, + enum rtrs_clt_state new_state) +{ + bool changed = false; + + spin_lock_irq(&clt_path->state_wq.lock); + if (clt_path->state == old_state) + changed = rtrs_clt_change_state(clt_path, new_state); + spin_unlock_irq(&clt_path->state_wq.lock); + + return changed; +} + +static void rtrs_clt_stop_and_destroy_conns(struct rtrs_clt_path *clt_path); +static void rtrs_rdma_error_recovery(struct rtrs_clt_con *con) +{ + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + + trace_rtrs_rdma_error_recovery(clt_path); + + if (rtrs_clt_change_state_from_to(clt_path, + RTRS_CLT_CONNECTED, + RTRS_CLT_RECONNECTING)) { + queue_work(rtrs_wq, &clt_path->err_recovery_work); + } 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(clt_path, + 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 = to_clt_con(wc->qp->qp_context); + + if (wc->status != IB_WC_SUCCESS) { + rtrs_err(con->c.path, "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 = to_clt_con(wc->qp->qp_context); + + if (wc->status != IB_WC_SUCCESS) { + rtrs_err(con->c.path, "Failed IB_WR_LOCAL_INV: %s\n", + ib_wc_status_msg(wc->status)); + rtrs_rdma_error_recovery(con); + } + req->need_inv = false; + if (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; + struct ib_send_wr wr = { + .opcode = IB_WR_LOCAL_INV, + .wr_cqe = &req->inv_cqe, + .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, NULL); +} + +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_path *clt_path; + int err; + + if (WARN_ON(!req->in_use)) + return; + if (WARN_ON(!req->con)) + return; + clt_path = to_clt_path(con->c.path); + + if (req->sg_cnt) { + if (req->dir == DMA_FROM_DEVICE && req->need_inv) { + /* + * We are here to invalidate read requests + * ourselves. In normal scenario server should + * send INV for all read requests, 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 (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; + } + + refcount_inc(&req->ref); + err = rtrs_inv_rkey(req); + if (err) { + rtrs_err(con->c.path, "Send INV WR key=%#x: %d\n", + req->mr->rkey, err); + } else if (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; + } + if (!refcount_dec_and_test(&req->ref)) + return; + } + ib_dma_unmap_sg(clt_path->s.dev->ib_dev, req->sglist, + req->sg_cnt, req->dir); + } + if (!refcount_dec_and_test(&req->ref)) + return; + if (req->mp_policy == MP_POLICY_MIN_INFLIGHT) + atomic_dec(&clt_path->stats->inflight); + + req->in_use = false; + req->con = NULL; + + if (errno) { + rtrs_err_rl(con->c.path, "IO request failed: error=%d path=%s [%s:%u] notify=%d\n", + errno, kobject_name(&clt_path->kobj), clt_path->hca_name, + clt_path->hca_port, notify); + } + + 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_path *clt_path = to_clt_path(con->c.path); + enum ib_send_flags flags; + struct ib_sge sge; + + if (!req->sg_size) { + rtrs_wrn(con->c.path, + "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 = clt_path->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->c.wr_cnt) % clt_path->s.signal_interval ? + 0 : IB_SEND_SIGNALED; + + ib_dma_sync_single_for_device(clt_path->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, NULL); +} + +static void process_io_rsp(struct rtrs_clt_path *clt_path, u32 msg_id, + s16 errno, bool w_inval) +{ + struct rtrs_clt_io_req *req; + + if (WARN_ON(msg_id >= clt_path->queue_depth)) + return; + + req = &clt_path->reqs[msg_id]; + /* Drop need_inv if server responded with send 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_path *clt_path = to_clt_path(con->c.path); + + WARN_ON((clt_path->flags & RTRS_MSG_NEW_RKEY_F) == 0); + iu = container_of(wc->wr_cqe, struct rtrs_iu, + cqe); + err = rtrs_iu_post_recv(&con->c, iu); + if (err) { + rtrs_err(con->c.path, "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_path *clt_path = to_clt_path(con->c.path); + 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((clt_path->flags & RTRS_MSG_NEW_RKEY_F) == 0); + + iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe); + + if (wc->byte_len < sizeof(*msg)) { + rtrs_err(con->c.path, "rkey response is malformed: size %d\n", + wc->byte_len); + goto out; + } + ib_dma_sync_single_for_cpu(clt_path->s.dev->ib_dev, iu->dma_addr, + iu->size, DMA_FROM_DEVICE); + msg = iu->buf; + if (le16_to_cpu(msg->type) != RTRS_MSG_RKEY_RSP) { + rtrs_err(clt_path->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 >= clt_path->queue_depth)) + goto out; + + rtrs_from_imm(be32_to_cpu(wc->ex.imm_data), &imm_type, &imm_payload); + if (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; + clt_path->rbufs[buf_id].rkey = le32_to_cpu(msg->rkey); + process_io_rsp(clt_path, msg_id, err, w_inval); + } + ib_dma_sync_single_for_device(clt_path->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 +}; + +/* + * Post x2 empty WRs: first is for this RDMA with IMM, + * second is for RECV with INV, which happened earlier. + */ +static int rtrs_post_recv_empty_x2(struct rtrs_con *con, struct ib_cqe *cqe) +{ + struct ib_recv_wr wr_arr[2], *wr; + int i; + + memset(wr_arr, 0, sizeof(wr_arr)); + for (i = 0; i < ARRAY_SIZE(wr_arr); i++) { + wr = &wr_arr[i]; + wr->wr_cqe = cqe; + if (i) + /* Chain backwards */ + wr->next = &wr_arr[i - 1]; + } + + return ib_post_recv(con->qp, wr, NULL); +} + +static void rtrs_clt_rdma_done(struct ib_cq *cq, struct ib_wc *wc) +{ + struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context); + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + u32 imm_type, imm_payload; + bool w_inval = false; + int err; + + if (wc->status != IB_WC_SUCCESS) { + if (wc->status != IB_WC_WR_FLUSH_ERR) { + rtrs_err(clt_path->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 (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(clt_path, msg_id, err, w_inval); + } else if (imm_type == RTRS_HB_MSG_IMM) { + WARN_ON(con->c.cid); + rtrs_send_hb_ack(&clt_path->s); + if (clt_path->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); + clt_path->s.hb_missed_cnt = 0; + clt_path->s.hb_cur_latency = + ktime_sub(ktime_get(), clt_path->s.hb_last_sent); + if (clt_path->flags & RTRS_MSG_NEW_RKEY_F) + return rtrs_clt_recv_done(con, wc); + } else { + rtrs_wrn(con->c.path, "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 (err) { + rtrs_err(con->c.path, "rtrs_post_recv_empty(): %d\n", + err); + rtrs_rdma_error_recovery(con); + } + 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 (clt_path->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(clt_path->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_path *clt_path = to_clt_path(con->c.path); + + for (i = 0; i < q_size; i++) { + if (clt_path->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 (err) + return err; + } + + return 0; +} + +static int post_recv_path(struct rtrs_clt_path *clt_path) +{ + size_t q_size = 0; + int err, cid; + + for (cid = 0; cid < clt_path->s.con_num; cid++) { + if (cid == 0) + q_size = SERVICE_CON_QUEUE_DEPTH; + else + q_size = clt_path->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(clt_path->s.con[cid]), q_size); + if (err) { + rtrs_err(clt_path->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_sess *clt; + struct rtrs_clt_path *(*next_path)(struct path_it *it); +}; + +/* + * rtrs_clt_get_next_path_or_null - get clt path from the list or return NULL + * @head: the head for the list. + * @clt_path: The element to take the next clt_path from. + * + * Next clt path returned in round-robin fashion, i.e. head will be skipped, + * but if list is observed as empty, NULL will be returned. + * + * This function 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(). + */ +static inline struct rtrs_clt_path * +rtrs_clt_get_next_path_or_null(struct list_head *head, struct rtrs_clt_path *clt_path) +{ + return list_next_or_null_rcu(head, &clt_path->s.entry, typeof(*clt_path), s.entry) ?: + list_next_or_null_rcu(head, + READ_ONCE((&clt_path->s.entry)->next), + typeof(*clt_path), s.entry); +} + +/** + * 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_path *get_next_path_rr(struct path_it *it) +{ + struct rtrs_clt_path __rcu **ppcpu_path; + struct rtrs_clt_path *path; + struct rtrs_clt_sess *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 (!path) + path = list_first_or_null_rcu(&clt->paths_list, + typeof(*path), s.entry); + else + path = rtrs_clt_get_next_path_or_null(&clt->paths_list, path); + + 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_path *get_next_path_min_inflight(struct path_it *it) +{ + struct rtrs_clt_path *min_path = NULL; + struct rtrs_clt_sess *clt = it->clt; + struct rtrs_clt_path *clt_path; + int min_inflight = INT_MAX; + int inflight; + + list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) { + if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED) + continue; + + if (!list_empty(raw_cpu_ptr(clt_path->mp_skip_entry))) + continue; + + inflight = atomic_read(&clt_path->stats->inflight); + + if (inflight < min_inflight) { + min_inflight = inflight; + min_path = clt_path; + } + } + + /* + * 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; +} + +/** + * get_next_path_min_latency() - Returns path with minimal latency. + * @it: the path pointer + * + * Return: a path with the lowest latency or NULL if all paths are tried + * + * Locks: + * rcu_read_lock() must be hold. + * + * Related to @MP_POLICY_MIN_LATENCY + * + * This DOES skip an already-tried path. + * There is a skip-list to skip a path if the path has tried but failed. + * It will try the minimum latency path and then the second minimum latency + * path and so on. Finally it will return NULL if all paths are tried. + * Therefore the caller MUST check the returned + * path is NULL and trigger the IO error. + */ +static struct rtrs_clt_path *get_next_path_min_latency(struct path_it *it) +{ + struct rtrs_clt_path *min_path = NULL; + struct rtrs_clt_sess *clt = it->clt; + struct rtrs_clt_path *clt_path; + ktime_t min_latency = KTIME_MAX; + ktime_t latency; + + list_for_each_entry_rcu(clt_path, &clt->paths_list, s.entry) { + if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED) + continue; + + if (!list_empty(raw_cpu_ptr(clt_path->mp_skip_entry))) + continue; + + latency = clt_path->s.hb_cur_latency; + + if (latency < min_latency) { + min_latency = latency; + min_path = clt_path; + } + } + + /* + * 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_sess *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 if (clt->mp_policy == MP_POLICY_MIN_INFLIGHT) + it->next_path = get_next_path_min_inflight; + else + it->next_path = get_next_path_min_latency; +} + +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 and MIN_LATENCY policies. + * 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. + * @req: an io request holding information about IO. + * @clt_path: client path + * @conf: conformation callback function to notify upper layer. + * @permit: permit for allocation of RDMA remote buffer + * @priv: private pointer + * @vec: kernel vector containing control message + * @usr_len: length of the user message + * @sg: scater list for IO data + * @sg_cnt: number of scater list entries + * @data_len: length of the IO data + * @dir: direction of the IO. + */ +static void rtrs_clt_init_req(struct rtrs_clt_io_req *req, + struct rtrs_clt_path *clt_path, + void (*conf)(void *priv, int errno), + 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(clt_path, permit); + req->conf = conf; + req->need_inv = false; + req->need_inv_comp = false; + req->inv_errno = 0; + refcount_set(&req->ref, 1); + req->mp_policy = clt_path->clt->mp_policy; + + 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); +} + +static struct rtrs_clt_io_req * +rtrs_clt_get_req(struct rtrs_clt_path *clt_path, + void (*conf)(void *priv, int errno), + 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 = &clt_path->reqs[permit->mem_id]; + rtrs_clt_init_req(req, clt_path, conf, permit, priv, vec, usr_len, + sg, sg_cnt, data_len, dir); + return req; +} + +static struct rtrs_clt_io_req * +rtrs_clt_get_copy_req(struct rtrs_clt_path *alive_path, + 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_path->reqs[fail_req->permit->mem_id]; + rtrs_clt_init_req(req, alive_path, 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, bool fr_en, + u32 count, u32 size, u32 imm, + struct ib_send_wr *wr, + struct ib_send_wr *tail) +{ + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + struct ib_sge *sge = req->sge; + enum ib_send_flags flags; + struct scatterlist *sg; + size_t num_sge; + int i; + struct ib_send_wr *ptail = NULL; + + if (fr_en) { + i = 0; + sge[i].addr = req->mr->iova; + sge[i].length = req->mr->length; + sge[i].lkey = req->mr->lkey; + i++; + num_sge = 2; + ptail = tail; + } else { + for_each_sg(req->sglist, sg, count, i) { + sge[i].addr = sg_dma_address(sg); + sge[i].length = sg_dma_len(sg); + sge[i].lkey = clt_path->s.dev->ib_pd->local_dma_lkey; + } + num_sge = 1 + count; + } + sge[i].addr = req->iu->dma_addr; + sge[i].length = size; + sge[i].lkey = clt_path->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->c.wr_cnt) % clt_path->s.signal_interval ? + 0 : IB_SEND_SIGNALED; + + ib_dma_sync_single_for_device(clt_path->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, wr, ptail); +} + +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 (nr < 0) + return nr; + if (nr < req->sg_cnt) + return -EINVAL; + ib_update_fast_reg_key(req->mr, ib_inc_rkey(req->mr->rkey)); + + return nr; +} + +static int rtrs_clt_write_req(struct rtrs_clt_io_req *req) +{ + struct rtrs_clt_con *con = req->con; + struct rtrs_path *s = con->c.path; + struct rtrs_clt_path *clt_path = to_clt_path(s); + struct rtrs_msg_rdma_write *msg; + + struct rtrs_rbuf *rbuf; + int ret, count = 0; + u32 imm, buf_id; + struct ib_reg_wr rwr; + struct ib_send_wr inv_wr; + struct ib_send_wr *wr = NULL; + bool fr_en = false; + + const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len; + + if (tsize > clt_path->chunk_size) { + rtrs_wrn(s, "Write request failed, size too big %zu > %d\n", + tsize, clt_path->chunk_size); + return -EMSGSIZE; + } + if (req->sg_cnt) { + count = ib_dma_map_sg(clt_path->s.dev->ib_dev, req->sglist, + req->sg_cnt, req->dir); + if (!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 = &clt_path->rbufs[buf_id]; + + if (count) { + ret = rtrs_map_sg_fr(req, count); + if (ret < 0) { + rtrs_err_rl(s, + "Write request failed, failed to map fast reg. data, err: %d\n", + ret); + ib_dma_unmap_sg(clt_path->s.dev->ib_dev, req->sglist, + req->sg_cnt, req->dir); + return ret; + } + inv_wr = (struct ib_send_wr) { + .opcode = IB_WR_LOCAL_INV, + .wr_cqe = &req->inv_cqe, + .send_flags = IB_SEND_SIGNALED, + .ex.invalidate_rkey = req->mr->rkey, + }; + req->inv_cqe.done = rtrs_clt_inv_rkey_done; + rwr = (struct ib_reg_wr) { + .wr.opcode = IB_WR_REG_MR, + .wr.wr_cqe = &fast_reg_cqe, + .mr = req->mr, + .key = req->mr->rkey, + .access = (IB_ACCESS_LOCAL_WRITE), + }; + wr = &rwr.wr; + fr_en = true; + refcount_inc(&req->ref); + } + /* + * 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, fr_en, count, + req->usr_len + sizeof(*msg), + imm, wr, &inv_wr); + if (ret) { + rtrs_err_rl(s, + "Write request failed: error=%d path=%s [%s:%u]\n", + ret, kobject_name(&clt_path->kobj), clt_path->hca_name, + clt_path->hca_port); + if (req->mp_policy == MP_POLICY_MIN_INFLIGHT) + atomic_dec(&clt_path->stats->inflight); + if (req->sg_cnt) + ib_dma_unmap_sg(clt_path->s.dev->ib_dev, req->sglist, + req->sg_cnt, req->dir); + } + + return ret; +} + +static int rtrs_clt_read_req(struct rtrs_clt_io_req *req) +{ + struct rtrs_clt_con *con = req->con; + struct rtrs_path *s = con->c.path; + struct rtrs_clt_path *clt_path = to_clt_path(s); + struct rtrs_msg_rdma_read *msg; + struct rtrs_ib_dev *dev = clt_path->s.dev; + + struct ib_reg_wr rwr; + struct ib_send_wr *wr = NULL; + + int ret, count = 0; + u32 imm, buf_id; + + const size_t tsize = sizeof(*msg) + req->data_len + req->usr_len; + + if (tsize > clt_path->chunk_size) { + rtrs_wrn(s, + "Read request failed, message size is %zu, bigger than CHUNK_SIZE %d\n", + tsize, clt_path->chunk_size); + return -EMSGSIZE; + } + + if (req->sg_cnt) { + count = ib_dma_map_sg(dev->ib_dev, req->sglist, req->sg_cnt, + req->dir); + if (!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) { + 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; + } + rwr = (struct ib_reg_wr) { + .wr.opcode = IB_WR_REG_MR, + .wr.wr_cqe = &fast_reg_cqe, + .mr = req->mr, + .key = req->mr->rkey, + .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 = 0; + msg->flags = 0; + } + /* + * 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, &clt_path->rbufs[buf_id], + req->data_len, imm, wr); + if (ret) { + rtrs_err_rl(s, + "Read request failed: error=%d path=%s [%s:%u]\n", + ret, kobject_name(&clt_path->kobj), clt_path->hca_name, + clt_path->hca_port); + if (req->mp_policy == MP_POLICY_MIN_INFLIGHT) + atomic_dec(&clt_path->stats->inflight); + 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 + * @clt: clt context + * @fail_req: a failed io request. + */ +static int rtrs_clt_failover_req(struct rtrs_clt_sess *clt, + struct rtrs_clt_io_req *fail_req) +{ + struct rtrs_clt_path *alive_path; + struct rtrs_clt_io_req *req; + int err = -ECONNABORTED; + struct path_it it; + + rcu_read_lock(); + for (path_it_init(&it, clt); + (alive_path = it.next_path(&it)) && it.i < it.clt->paths_num; + it.i++) { + if (READ_ONCE(alive_path->state) != RTRS_CLT_CONNECTED) + continue; + req = rtrs_clt_get_copy_req(alive_path, fail_req); + if (req->dir == DMA_TO_DEVICE) + err = rtrs_clt_write_req(req); + else + err = rtrs_clt_read_req(req); + if (err) { + req->in_use = false; + continue; + } + /* Success path */ + rtrs_clt_inc_failover_cnt(alive_path->stats); + break; + } + path_it_deinit(&it); + rcu_read_unlock(); + + return err; +} + +static void fail_all_outstanding_reqs(struct rtrs_clt_path *clt_path) +{ + struct rtrs_clt_sess *clt = clt_path->clt; + struct rtrs_clt_io_req *req; + int i, err; + + if (!clt_path->reqs) + return; + for (i = 0; i < clt_path->queue_depth; ++i) { + req = &clt_path->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 (err) + /* Failover failed, notify anyway */ + req->conf(req->priv, err); + } +} + +static void free_path_reqs(struct rtrs_clt_path *clt_path) +{ + struct rtrs_clt_io_req *req; + int i; + + if (!clt_path->reqs) + return; + for (i = 0; i < clt_path->queue_depth; ++i) { + req = &clt_path->reqs[i]; + if (req->mr) + ib_dereg_mr(req->mr); + kfree(req->sge); + rtrs_iu_free(req->iu, clt_path->s.dev->ib_dev, 1); + } + kfree(clt_path->reqs); + clt_path->reqs = NULL; +} + +static int alloc_path_reqs(struct rtrs_clt_path *clt_path) +{ + struct rtrs_clt_io_req *req; + int i, err = -ENOMEM; + + clt_path->reqs = kcalloc(clt_path->queue_depth, + sizeof(*clt_path->reqs), + GFP_KERNEL); + if (!clt_path->reqs) + return -ENOMEM; + + for (i = 0; i < clt_path->queue_depth; ++i) { + req = &clt_path->reqs[i]; + req->iu = rtrs_iu_alloc(1, clt_path->max_hdr_size, GFP_KERNEL, + clt_path->s.dev->ib_dev, + DMA_TO_DEVICE, + rtrs_clt_rdma_done); + if (!req->iu) + goto out; + + req->sge = kcalloc(2, sizeof(*req->sge), GFP_KERNEL); + if (!req->sge) + goto out; + + req->mr = ib_alloc_mr(clt_path->s.dev->ib_pd, + IB_MR_TYPE_MEM_REG, + clt_path->max_pages_per_mr); + if (IS_ERR(req->mr)) { + err = PTR_ERR(req->mr); + req->mr = NULL; + pr_err("Failed to alloc clt_path->max_pages_per_mr %d\n", + clt_path->max_pages_per_mr); + goto out; + } + + init_completion(&req->inv_comp); + } + + return 0; + +out: + free_path_reqs(clt_path); + + return err; +} + +static int alloc_permits(struct rtrs_clt_sess *clt) +{ + unsigned int chunk_bits; + int err, i; + + clt->permits_map = bitmap_zalloc(clt->queue_depth, GFP_KERNEL); + if (!clt->permits_map) { + err = -ENOMEM; + goto out_err; + } + clt->permits = kcalloc(clt->queue_depth, permit_size(clt), GFP_KERNEL); + if (!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: + bitmap_free(clt->permits_map); + clt->permits_map = NULL; +out_err: + return err; +} + +static void free_permits(struct rtrs_clt_sess *clt) +{ + if (clt->permits_map) + wait_event(clt->permits_wait, + bitmap_empty(clt->permits_map, clt->queue_depth)); + + bitmap_free(clt->permits_map); + clt->permits_map = NULL; + kfree(clt->permits); + clt->permits = NULL; +} + +static void query_fast_reg_mode(struct rtrs_clt_path *clt_path) +{ + struct ib_device *ib_dev; + u64 max_pages_per_mr; + int mr_page_shift; + + ib_dev = clt_path->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)); + clt_path->max_pages_per_mr = + min3(clt_path->max_pages_per_mr, (u32)max_pages_per_mr, + ib_dev->attrs.max_fast_reg_page_list_len); + clt_path->clt->max_segments = + min(clt_path->max_pages_per_mr, clt_path->clt->max_segments); +} + +static bool rtrs_clt_change_state_get_old(struct rtrs_clt_path *clt_path, + enum rtrs_clt_state new_state, + enum rtrs_clt_state *old_state) +{ + bool changed; + + spin_lock_irq(&clt_path->state_wq.lock); + if (old_state) + *old_state = clt_path->state; + changed = rtrs_clt_change_state(clt_path, new_state); + spin_unlock_irq(&clt_path->state_wq.lock); + + return changed; +} + +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_path *clt_path) +{ + rtrs_init_hb(&clt_path->s, &io_comp_cqe, + RTRS_HB_INTERVAL_MS, + RTRS_HB_MISSED_MAX, + rtrs_clt_hb_err_handler, + rtrs_wq); +} + +static void rtrs_clt_reconnect_work(struct work_struct *work); +static void rtrs_clt_close_work(struct work_struct *work); + +static void rtrs_clt_err_recovery_work(struct work_struct *work) +{ + struct rtrs_clt_path *clt_path; + struct rtrs_clt_sess *clt; + int delay_ms; + + clt_path = container_of(work, struct rtrs_clt_path, err_recovery_work); + clt = clt_path->clt; + delay_ms = clt->reconnect_delay_sec * 1000; + rtrs_clt_stop_and_destroy_conns(clt_path); + queue_delayed_work(rtrs_wq, &clt_path->reconnect_dwork, + msecs_to_jiffies(delay_ms + + prandom_u32_max(RTRS_RECONNECT_SEED))); +} + +static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt, + const struct rtrs_addr *path, + size_t con_num, u32 nr_poll_queues) +{ + struct rtrs_clt_path *clt_path; + int err = -ENOMEM; + int cpu; + size_t total_con; + + clt_path = kzalloc(sizeof(*clt_path), GFP_KERNEL); + if (!clt_path) + goto err; + + /* + * irqmode and poll + * +1: Extra connection for user messages + */ + total_con = con_num + nr_poll_queues + 1; + clt_path->s.con = kcalloc(total_con, sizeof(*clt_path->s.con), + GFP_KERNEL); + if (!clt_path->s.con) + goto err_free_path; + + clt_path->s.con_num = total_con; + clt_path->s.irq_con_num = con_num + 1; + + clt_path->stats = kzalloc(sizeof(*clt_path->stats), GFP_KERNEL); + if (!clt_path->stats) + goto err_free_con; + + mutex_init(&clt_path->init_mutex); + uuid_gen(&clt_path->s.uuid); + memcpy(&clt_path->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(&clt_path->s.src_addr, path->src, + rdma_addr_size((struct sockaddr *)path->src)); + strscpy(clt_path->s.sessname, clt->sessname, + sizeof(clt_path->s.sessname)); + clt_path->clt = clt; + clt_path->max_pages_per_mr = RTRS_MAX_SEGMENTS; + init_waitqueue_head(&clt_path->state_wq); + clt_path->state = RTRS_CLT_CONNECTING; + atomic_set(&clt_path->connected_cnt, 0); + INIT_WORK(&clt_path->close_work, rtrs_clt_close_work); + INIT_WORK(&clt_path->err_recovery_work, rtrs_clt_err_recovery_work); + INIT_DELAYED_WORK(&clt_path->reconnect_dwork, rtrs_clt_reconnect_work); + rtrs_clt_init_hb(clt_path); + + clt_path->mp_skip_entry = alloc_percpu(typeof(*clt_path->mp_skip_entry)); + if (!clt_path->mp_skip_entry) + goto err_free_stats; + + for_each_possible_cpu(cpu) + INIT_LIST_HEAD(per_cpu_ptr(clt_path->mp_skip_entry, cpu)); + + err = rtrs_clt_init_stats(clt_path->stats); + if (err) + goto err_free_percpu; + + return clt_path; + +err_free_percpu: + free_percpu(clt_path->mp_skip_entry); +err_free_stats: + kfree(clt_path->stats); +err_free_con: + kfree(clt_path->s.con); +err_free_path: + kfree(clt_path); +err: + return ERR_PTR(err); +} + +void free_path(struct rtrs_clt_path *clt_path) +{ + free_percpu(clt_path->mp_skip_entry); + mutex_destroy(&clt_path->init_mutex); + kfree(clt_path->s.con); + kfree(clt_path->rbufs); + kfree(clt_path); +} + +static int create_con(struct rtrs_clt_path *clt_path, unsigned int cid) +{ + struct rtrs_clt_con *con; + + con = kzalloc(sizeof(*con), GFP_KERNEL); + if (!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.path = &clt_path->s; + /* Align with srv, init as 1 */ + atomic_set(&con->c.wr_cnt, 1); + mutex_init(&con->con_mutex); + + clt_path->s.con[cid] = &con->c; + + return 0; +} + +static void destroy_con(struct rtrs_clt_con *con) +{ + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + + clt_path->s.con[con->c.cid] = NULL; + mutex_destroy(&con->con_mutex); + kfree(con); +} + +static int create_con_cq_qp(struct rtrs_clt_con *con) +{ + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + u32 max_send_wr, max_recv_wr, cq_num, max_send_sge, wr_limit; + int err, cq_vector; + struct rtrs_msg_rkey_rsp *rsp; + + lockdep_assert_held(&con->con_mutex); + if (con->c.cid == 0) { + max_send_sge = 1; + /* We must be the first here */ + if (WARN_ON(clt_path->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. + */ + clt_path->s.dev = rtrs_ib_dev_find_or_add(con->c.cm_id->device, + &dev_pd); + if (!clt_path->s.dev) { + rtrs_wrn(clt_path->clt, + "rtrs_ib_dev_find_get_or_add(): no memory\n"); + return -ENOMEM; + } + clt_path->s.dev_ref = 1; + query_fast_reg_mode(clt_path); + wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr; + /* + * Two (request + registration) completion for send + * Two for recv if always_invalidate is set on server + * or one for recv. + * + 2 for drain and heartbeat + * in case qp gets into error state. + */ + max_send_wr = + min_t(int, wr_limit, SERVICE_CON_QUEUE_DEPTH * 2 + 2); + max_recv_wr = max_send_wr; + } 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(!clt_path->s.dev)) + return -EINVAL; + if (WARN_ON(!clt_path->queue_depth)) + return -EINVAL; + + wr_limit = clt_path->s.dev->ib_dev->attrs.max_qp_wr; + /* Shared between connections */ + clt_path->s.dev_ref++; + max_send_wr = min_t(int, wr_limit, + /* QD * (REQ + RSP + FR REGS or INVS) + drain */ + clt_path->queue_depth * 3 + 1); + max_recv_wr = min_t(int, wr_limit, + clt_path->queue_depth * 3 + 1); + max_send_sge = 2; + } + atomic_set(&con->c.sq_wr_avail, max_send_wr); + cq_num = max_send_wr + max_recv_wr; + /* alloc iu to recv new rkey reply when server reports flags set */ + if (clt_path->flags & RTRS_MSG_NEW_RKEY_F || con->c.cid == 0) { + con->rsp_ius = rtrs_iu_alloc(cq_num, sizeof(*rsp), + GFP_KERNEL, + clt_path->s.dev->ib_dev, + DMA_FROM_DEVICE, + rtrs_clt_rdma_done); + if (!con->rsp_ius) + return -ENOMEM; + con->queue_num = cq_num; + } + cq_num = max_send_wr + max_recv_wr; + cq_vector = con->cpu % clt_path->s.dev->ib_dev->num_comp_vectors; + if (con->c.cid >= clt_path->s.irq_con_num) + err = rtrs_cq_qp_create(&clt_path->s, &con->c, max_send_sge, + cq_vector, cq_num, max_send_wr, + max_recv_wr, IB_POLL_DIRECT); + else + err = rtrs_cq_qp_create(&clt_path->s, &con->c, max_send_sge, + cq_vector, cq_num, max_send_wr, + max_recv_wr, IB_POLL_SOFTIRQ); + /* + * In case of error we do not bother to clean previous allocations, + * since destroy_con_cq_qp() must be called. + */ + return err; +} + +static void destroy_con_cq_qp(struct rtrs_clt_con *con) +{ + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + + /* + * Be careful here: destroy_con_cq_qp() can be called even + * create_con_cq_qp() failed, see comments there. + */ + lockdep_assert_held(&con->con_mutex); + rtrs_cq_qp_destroy(&con->c); + if (con->rsp_ius) { + rtrs_iu_free(con->rsp_ius, clt_path->s.dev->ib_dev, + con->queue_num); + con->rsp_ius = NULL; + con->queue_num = 0; + } + if (clt_path->s.dev_ref && !--clt_path->s.dev_ref) { + rtrs_ib_dev_put(clt_path->s.dev); + clt_path->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_path *s = con->c.path; + int err; + + mutex_lock(&con->con_mutex); + err = create_con_cq_qp(con); + mutex_unlock(&con->con_mutex); + if (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 (err) + rtrs_err(s, "Resolving route failed, err: %d\n", err); + + return err; +} + +static int rtrs_rdma_route_resolved(struct rtrs_clt_con *con) +{ + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + struct rtrs_clt_sess *clt = clt_path->clt; + struct rtrs_msg_conn_req msg; + struct rdma_conn_param param; + + int err; + + param = (struct rdma_conn_param) { + .retry_count = 7, + .rnr_retry_count = 7, + .private_data = &msg, + .private_data_len = sizeof(msg), + }; + + msg = (struct rtrs_msg_conn_req) { + .magic = cpu_to_le16(RTRS_MAGIC), + .version = cpu_to_le16(RTRS_PROTO_VER), + .cid = cpu_to_le16(con->c.cid), + .cid_num = cpu_to_le16(clt_path->s.con_num), + .recon_cnt = cpu_to_le16(clt_path->s.recon_cnt), + }; + msg.first_conn = clt_path->for_new_clt ? FIRST_CONN : 0; + uuid_copy(&msg.sess_uuid, &clt_path->s.uuid); + uuid_copy(&msg.paths_uuid, &clt->paths_uuid); + + err = rdma_connect_locked(con->c.cm_id, ¶m); + if (err) + rtrs_err(clt, "rdma_connect_locked(): %d\n", err); + + return err; +} + +static int rtrs_rdma_conn_established(struct rtrs_clt_con *con, + struct rdma_cm_event *ev) +{ + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + struct rtrs_clt_sess *clt = clt_path->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 (len < sizeof(*msg)) { + rtrs_err(clt, "Invalid RTRS connection response\n"); + return -ECONNRESET; + } + if (le16_to_cpu(msg->magic) != RTRS_MAGIC) { + rtrs_err(clt, "Invalid RTRS magic\n"); + return -ECONNRESET; + } + version = le16_to_cpu(msg->version); + if (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 (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 (clt_path->queue_depth > 0 && queue_depth != clt_path->queue_depth) { + rtrs_err(clt, "Error: queue depth changed\n"); + + /* + * Stop any more reconnection attempts + */ + clt_path->reconnect_attempts = -1; + rtrs_err(clt, + "Disabling auto-reconnect. Trigger a manual reconnect after issue is resolved\n"); + return -ECONNRESET; + } + + if (!clt_path->rbufs) { + clt_path->rbufs = kcalloc(queue_depth, + sizeof(*clt_path->rbufs), + GFP_KERNEL); + if (!clt_path->rbufs) + return -ENOMEM; + } + clt_path->queue_depth = queue_depth; + clt_path->s.signal_interval = min_not_zero(queue_depth, + (unsigned short) SERVICE_CON_QUEUE_DEPTH); + clt_path->max_hdr_size = le32_to_cpu(msg->max_hdr_size); + clt_path->max_io_size = le32_to_cpu(msg->max_io_size); + clt_path->flags = le32_to_cpu(msg->flags); + clt_path->chunk_size = clt_path->max_io_size + clt_path->max_hdr_size; + + /* + * Global 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 = clt_path->queue_depth; + clt->max_io_size = min_not_zero(clt_path->max_io_size, + clt->max_io_size); + mutex_unlock(&clt->paths_mutex); + + /* + * Cache the hca_port and hca_name for sysfs + */ + clt_path->hca_port = con->c.cm_id->port_num; + scnprintf(clt_path->hca_name, sizeof(clt_path->hca_name), + clt_path->s.dev->ib_dev->name); + clt_path->s.src_addr = con->c.cm_id->route.addr.src_addr; + /* set for_new_clt, to allow future reconnect on any path */ + clt_path->for_new_clt = 1; + } + + return 0; +} + +static inline void flag_success_on_conn(struct rtrs_clt_con *con) +{ + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + + atomic_inc(&clt_path->connected_cnt); + con->cm_err = 1; +} + +static int rtrs_rdma_conn_rejected(struct rtrs_clt_con *con, + struct rdma_cm_event *ev) +{ + struct rtrs_path *s = con->c.path; + 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; +} + +void rtrs_clt_close_conns(struct rtrs_clt_path *clt_path, bool wait) +{ + trace_rtrs_clt_close_conns(clt_path); + + if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CLOSING, NULL)) + queue_work(rtrs_wq, &clt_path->close_work); + if (wait) + flush_work(&clt_path->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_path *clt_path; + + clt_path = to_clt_path(con->c.path); + if (atomic_dec_and_test(&clt_path->connected_cnt)) + + wake_up(&clt_path->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_path *s = con->c.path; + struct rtrs_clt_path *clt_path = to_clt_path(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: + cm_err = rtrs_rdma_conn_established(con, ev); + if (!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(&clt_path->state_wq); + return 0; + } + break; + case RDMA_CM_EVENT_REJECTED: + cm_err = rtrs_rdma_conn_rejected(con, ev); + break; + case RDMA_CM_EVENT_DISCONNECTED: + /* No message for disconnecting */ + cm_err = -ECONNRESET; + break; + case RDMA_CM_EVENT_CONNECT_ERROR: + case RDMA_CM_EVENT_UNREACHABLE: + case RDMA_CM_EVENT_ADDR_CHANGE: + case RDMA_CM_EVENT_TIMEWAIT_EXIT: + rtrs_wrn(s, "CM error (CM event: %s, err: %d)\n", + rdma_event_msg(ev->event), ev->status); + cm_err = -ECONNRESET; + break; + case RDMA_CM_EVENT_ADDR_ERROR: + case RDMA_CM_EVENT_ROUTE_ERROR: + rtrs_wrn(s, "CM error (CM event: %s, err: %d)\n", + rdma_event_msg(ev->event), ev->status); + cm_err = -EHOSTUNREACH; + break; + case RDMA_CM_EVENT_DEVICE_REMOVAL: + /* + * Device removal is a special case. Queue close and return 0. + */ + rtrs_clt_close_conns(clt_path, false); + return 0; + default: + rtrs_err(s, "Unexpected RDMA CM error (CM event: %s, err: %d)\n", + rdma_event_msg(ev->event), ev->status); + 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_path *s = con->c.path; + struct rtrs_clt_path *clt_path = to_clt_path(s); + struct rdma_cm_id *cm_id; + int err; + + cm_id = rdma_create_id(&init_net, rtrs_clt_rdma_cm_handler, con, + clt_path->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 *)&clt_path->s.src_addr, + (struct sockaddr *)&clt_path->s.dst_addr, + RTRS_CONNECT_TIMEOUT_MS); + if (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( + clt_path->state_wq, + con->cm_err || clt_path->state != RTRS_CLT_CONNECTING, + msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS)); + if (err == 0 || err == -ERESTARTSYS) { + if (err == 0) + err = -ETIMEDOUT; + /* Timedout or interrupted */ + goto errr; + } + if (con->cm_err < 0) { + err = con->cm_err; + goto errr; + } + if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTING) { + /* Device removal */ + err = -ECONNABORTED; + goto errr; + } + + return 0; + +errr: + stop_cm(con); + mutex_lock(&con->con_mutex); + destroy_con_cq_qp(con); + mutex_unlock(&con->con_mutex); +destroy_cm: + destroy_cm(con); + + return err; +} + +static void rtrs_clt_path_up(struct rtrs_clt_path *clt_path) +{ + struct rtrs_clt_sess *clt = clt_path->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 */ + clt_path->established = true; + clt_path->reconnect_attempts = 0; + clt_path->stats->reconnects.successful_cnt++; +} + +static void rtrs_clt_path_down(struct rtrs_clt_path *clt_path) +{ + struct rtrs_clt_sess *clt = clt_path->clt; + + if (!clt_path->established) + return; + + clt_path->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_path *clt_path) +{ + struct rtrs_clt_con *con; + unsigned int cid; + + WARN_ON(READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTED); + + /* + * Possible race with rtrs_clt_open(), when DEVICE_REMOVAL comes + * exactly in between. Start destroying after it finishes. + */ + mutex_lock(&clt_path->init_mutex); + mutex_unlock(&clt_path->init_mutex); + + /* + * All IO paths must observe !CONNECTED state before we + * free everything. + */ + synchronize_rcu(); + + rtrs_stop_hb(&clt_path->s); + + /* + * 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 < clt_path->s.con_num; cid++) { + if (!clt_path->s.con[cid]) + break; + con = to_clt_con(clt_path->s.con[cid]); + stop_cm(con); + } + fail_all_outstanding_reqs(clt_path); + free_path_reqs(clt_path); + rtrs_clt_path_down(clt_path); + + /* + * 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(clt_path->state_wq, + !atomic_read(&clt_path->connected_cnt), + msecs_to_jiffies(RTRS_CONNECT_TIMEOUT_MS)); + + for (cid = 0; cid < clt_path->s.con_num; cid++) { + if (!clt_path->s.con[cid]) + break; + con = to_clt_con(clt_path->s.con[cid]); + mutex_lock(&con->con_mutex); + destroy_con_cq_qp(con); + mutex_unlock(&con->con_mutex); + destroy_cm(con); + destroy_con(con); + } +} + +static void rtrs_clt_remove_path_from_arr(struct rtrs_clt_path *clt_path) +{ + struct rtrs_clt_sess *clt = clt_path->clt; + struct rtrs_clt_path *next; + bool wait_for_grace = false; + int cpu; + + mutex_lock(&clt->paths_mutex); + list_del_rcu(&clt_path->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. + */ + rcu_read_lock(); + next = rtrs_clt_get_next_path_or_null(&clt->paths_list, clt_path); + rcu_read_unlock(); + + /* + * @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_path __rcu **ppcpu_path; + + ppcpu_path = per_cpu_ptr(clt->pcpu_path, cpu); + if (rcu_dereference_protected(*ppcpu_path, + lockdep_is_held(&clt->paths_mutex)) != clt_path) + /* + * 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 (try_cmpxchg((struct rtrs_clt_path **)ppcpu_path, &clt_path, + 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_path *clt_path) +{ + struct rtrs_clt_sess *clt = clt_path->clt; + + mutex_lock(&clt->paths_mutex); + clt->paths_num++; + + list_add_tail_rcu(&clt_path->s.entry, &clt->paths_list); + mutex_unlock(&clt->paths_mutex); +} + +static void rtrs_clt_close_work(struct work_struct *work) +{ + struct rtrs_clt_path *clt_path; + + clt_path = container_of(work, struct rtrs_clt_path, close_work); + + cancel_work_sync(&clt_path->err_recovery_work); + cancel_delayed_work_sync(&clt_path->reconnect_dwork); + rtrs_clt_stop_and_destroy_conns(clt_path); + rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CLOSED, NULL); +} + +static int init_conns(struct rtrs_clt_path *clt_path) +{ + 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. + */ + clt_path->s.recon_cnt++; + + /* Establish all RDMA connections */ + for (cid = 0; cid < clt_path->s.con_num; cid++) { + err = create_con(clt_path, cid); + if (err) + goto destroy; + + err = create_cm(to_clt_con(clt_path->s.con[cid])); + if (err) { + destroy_con(to_clt_con(clt_path->s.con[cid])); + goto destroy; + } + } + err = alloc_path_reqs(clt_path); + if (err) + goto destroy; + + rtrs_start_hb(&clt_path->s); + + return 0; + +destroy: + while (cid--) { + struct rtrs_clt_con *con = to_clt_con(clt_path->s.con[cid]); + + stop_cm(con); + + mutex_lock(&con->con_mutex); + destroy_con_cq_qp(con); + mutex_unlock(&con->con_mutex); + 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_get_old(clt_path, RTRS_CLT_CONNECTING_ERR, NULL); + + return err; +} + +static void rtrs_clt_info_req_done(struct ib_cq *cq, struct ib_wc *wc) +{ + struct rtrs_clt_con *con = to_clt_con(wc->qp->qp_context); + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + struct rtrs_iu *iu; + + iu = container_of(wc->wr_cqe, struct rtrs_iu, cqe); + rtrs_iu_free(iu, clt_path->s.dev->ib_dev, 1); + + if (wc->status != IB_WC_SUCCESS) { + rtrs_err(clt_path->clt, "Path info request send failed: %s\n", + ib_wc_status_msg(wc->status)); + rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CONNECTING_ERR, NULL); + return; + } + + rtrs_clt_update_wc_stats(con); +} + +static int process_info_rsp(struct rtrs_clt_path *clt_path, + 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 (!sg_cnt || (clt_path->queue_depth % sg_cnt)) { + rtrs_err(clt_path->clt, + "Incorrect sg_cnt %d, is not multiple\n", + 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 ((ilog2(sg_cnt - 1) + 1) + (ilog2(clt_path->chunk_size - 1) + 1) > + MAX_IMM_PAYL_BITS) { + rtrs_err(clt_path->clt, + "RDMA immediate size (%db) not enough to encode %d buffers of size %dB\n", + MAX_IMM_PAYL_BITS, sg_cnt, clt_path->chunk_size); + return -EINVAL; + } + total_len = 0; + for (sgi = 0, i = 0; sgi < sg_cnt && i < clt_path->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 (!len || (len % clt_path->chunk_size)) { + rtrs_err(clt_path->clt, "Incorrect [%d].len %d\n", + sgi, + len); + return -EINVAL; + } + for ( ; len && i < clt_path->queue_depth; i++) { + clt_path->rbufs[i].addr = addr; + clt_path->rbufs[i].rkey = rkey; + + len -= clt_path->chunk_size; + addr += clt_path->chunk_size; + } + } + /* Sanity check */ + if (sgi != sg_cnt || i != clt_path->queue_depth) { + rtrs_err(clt_path->clt, + "Incorrect sg vector, not fully mapped\n"); + return -EINVAL; + } + if (total_len != clt_path->chunk_size * clt_path->queue_depth) { + rtrs_err(clt_path->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 = to_clt_con(wc->qp->qp_context); + struct rtrs_clt_path *clt_path = to_clt_path(con->c.path); + 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 (wc->status != IB_WC_SUCCESS) { + rtrs_err(clt_path->clt, "Path info response recv failed: %s\n", + ib_wc_status_msg(wc->status)); + goto out; + } + WARN_ON(wc->opcode != IB_WC_RECV); + + if (wc->byte_len < sizeof(*msg)) { + rtrs_err(clt_path->clt, "Path info response is malformed: size %d\n", + wc->byte_len); + goto out; + } + ib_dma_sync_single_for_cpu(clt_path->s.dev->ib_dev, iu->dma_addr, + iu->size, DMA_FROM_DEVICE); + msg = iu->buf; + if (le16_to_cpu(msg->type) != RTRS_MSG_INFO_RSP) { + rtrs_err(clt_path->clt, "Path 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 (wc->byte_len < rx_sz) { + rtrs_err(clt_path->clt, "Path info response is malformed: size %d\n", + wc->byte_len); + goto out; + } + err = process_info_rsp(clt_path, msg); + if (err) + goto out; + + err = post_recv_path(clt_path); + if (err) + goto out; + + state = RTRS_CLT_CONNECTED; + +out: + rtrs_clt_update_wc_stats(con); + rtrs_iu_free(iu, clt_path->s.dev->ib_dev, 1); + rtrs_clt_change_state_get_old(clt_path, state, NULL); +} + +static int rtrs_send_path_info(struct rtrs_clt_path *clt_path) +{ + struct rtrs_clt_con *usr_con = to_clt_con(clt_path->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(struct rtrs_sg_desc) * clt_path->queue_depth; + + tx_iu = rtrs_iu_alloc(1, sizeof(struct rtrs_msg_info_req), GFP_KERNEL, + clt_path->s.dev->ib_dev, DMA_TO_DEVICE, + rtrs_clt_info_req_done); + rx_iu = rtrs_iu_alloc(1, rx_sz, GFP_KERNEL, clt_path->s.dev->ib_dev, + DMA_FROM_DEVICE, rtrs_clt_info_rsp_done); + if (!tx_iu || !rx_iu) { + err = -ENOMEM; + goto out; + } + /* Prepare for getting info response */ + err = rtrs_iu_post_recv(&usr_con->c, rx_iu); + if (err) { + rtrs_err(clt_path->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->pathname, clt_path->s.sessname, sizeof(msg->pathname)); + + ib_dma_sync_single_for_device(clt_path->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 (err) { + rtrs_err(clt_path->clt, "rtrs_iu_post_send(), err: %d\n", err); + goto out; + } + tx_iu = NULL; + + /* Wait for state change */ + wait_event_interruptible_timeout(clt_path->state_wq, + clt_path->state != RTRS_CLT_CONNECTING, + msecs_to_jiffies( + RTRS_CONNECT_TIMEOUT_MS)); + if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED) { + if (READ_ONCE(clt_path->state) == RTRS_CLT_CONNECTING_ERR) + err = -ECONNRESET; + else + err = -ETIMEDOUT; + } + +out: + if (tx_iu) + rtrs_iu_free(tx_iu, clt_path->s.dev->ib_dev, 1); + if (rx_iu) + rtrs_iu_free(rx_iu, clt_path->s.dev->ib_dev, 1); + if (err) + /* If we've never taken async path because of malloc problems */ + rtrs_clt_change_state_get_old(clt_path, + RTRS_CLT_CONNECTING_ERR, NULL); + + return err; +} + +/** + * init_path() - establishes all path connections and does handshake + * @clt_path: client path. + * In case of error full close or reconnect procedure should be taken, + * because reconnect or close async works can be started. + */ +static int init_path(struct rtrs_clt_path *clt_path) +{ + int err; + char str[NAME_MAX]; + struct rtrs_addr path = { + .src = &clt_path->s.src_addr, + .dst = &clt_path->s.dst_addr, + }; + + rtrs_addr_to_str(&path, str, sizeof(str)); + + mutex_lock(&clt_path->init_mutex); + err = init_conns(clt_path); + if (err) { + rtrs_err(clt_path->clt, + "init_conns() failed: err=%d path=%s [%s:%u]\n", err, + str, clt_path->hca_name, clt_path->hca_port); + goto out; + } + err = rtrs_send_path_info(clt_path); + if (err) { + rtrs_err(clt_path->clt, + "rtrs_send_path_info() failed: err=%d path=%s [%s:%u]\n", + err, str, clt_path->hca_name, clt_path->hca_port); + goto out; + } + rtrs_clt_path_up(clt_path); +out: + mutex_unlock(&clt_path->init_mutex); + + return err; +} + +static void rtrs_clt_reconnect_work(struct work_struct *work) +{ + struct rtrs_clt_path *clt_path; + struct rtrs_clt_sess *clt; + int err; + + clt_path = container_of(to_delayed_work(work), struct rtrs_clt_path, + reconnect_dwork); + clt = clt_path->clt; + + trace_rtrs_clt_reconnect_work(clt_path); + + if (READ_ONCE(clt_path->state) != RTRS_CLT_RECONNECTING) + return; + + if (clt_path->reconnect_attempts >= clt->max_reconnect_attempts) { + /* Close a path completely if max attempts is reached */ + rtrs_clt_close_conns(clt_path, false); + return; + } + clt_path->reconnect_attempts++; + + msleep(RTRS_RECONNECT_BACKOFF); + if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_CONNECTING, NULL)) { + err = init_path(clt_path); + if (err) + goto reconnect_again; + } + + return; + +reconnect_again: + if (rtrs_clt_change_state_get_old(clt_path, RTRS_CLT_RECONNECTING, NULL)) { + clt_path->stats->reconnects.fail_cnt++; + queue_work(rtrs_wq, &clt_path->err_recovery_work); + } +} + +static void rtrs_clt_dev_release(struct device *dev) +{ + struct rtrs_clt_sess *clt = container_of(dev, struct rtrs_clt_sess, + dev); + + mutex_destroy(&clt->paths_ev_mutex); + mutex_destroy(&clt->paths_mutex); + kfree(clt); +} + +static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num, + u16 port, size_t pdu_sz, void *priv, + void (*link_ev)(void *priv, + enum rtrs_clt_link_ev ev), + unsigned int reconnect_delay_sec, + unsigned int max_reconnect_attempts) +{ + struct rtrs_clt_sess *clt; + int err; + + if (!paths_num || paths_num > MAX_PATHS_NUM) + return ERR_PTR(-EINVAL); + + if (strlen(sessname) >= sizeof(clt->sessname)) + return ERR_PTR(-EINVAL); + + clt = kzalloc(sizeof(*clt), GFP_KERNEL); + if (!clt) + return ERR_PTR(-ENOMEM); + + clt->pcpu_path = alloc_percpu(typeof(*clt->pcpu_path)); + if (!clt->pcpu_path) { + kfree(clt); + return ERR_PTR(-ENOMEM); + } + + clt->dev.class = rtrs_clt_dev_class; + clt->dev.release = rtrs_clt_dev_release; + 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 = RTRS_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; + strscpy(clt->sessname, sessname, sizeof(clt->sessname)); + init_waitqueue_head(&clt->permits_wait); + mutex_init(&clt->paths_ev_mutex); + mutex_init(&clt->paths_mutex); + device_initialize(&clt->dev); + + err = dev_set_name(&clt->dev, "%s", sessname); + if (err) + goto err_put; + + /* + * Suppress user space notification until + * sysfs files are created + */ + dev_set_uevent_suppress(&clt->dev, true); + err = device_add(&clt->dev); + if (err) + goto err_put; + + clt->kobj_paths = kobject_create_and_add("paths", &clt->dev.kobj); + if (!clt->kobj_paths) { + err = -ENOMEM; + goto err_del; + } + err = rtrs_clt_create_sysfs_root_files(clt); + if (err) { + kobject_del(clt->kobj_paths); + kobject_put(clt->kobj_paths); + goto err_del; + } + dev_set_uevent_suppress(&clt->dev, false); + kobject_uevent(&clt->dev.kobj, KOBJ_ADD); + + return clt; +err_del: + device_del(&clt->dev); +err_put: + free_percpu(clt->pcpu_path); + put_device(&clt->dev); + return ERR_PTR(err); +} + +static void free_clt(struct rtrs_clt_sess *clt) +{ + free_percpu(clt->pcpu_path); + + /* + * release callback will free clt and destroy mutexes in last put + */ + device_unregister(&clt->dev); +} + +/** + * rtrs_clt_open() - Open a path to an RTRS server + * @ops: holds the link event callback and the private pointer. + * @pathname: name of the path to an RTRS server + * @paths: Paths to be established defined by their src and dst addresses + * @paths_num: Number of elements in the @paths array + * @port: port to be used by the RTRS session + * @pdu_sz: Size of extra payload which can be accessed after permit allocation. + * @reconnect_delay_sec: time between reconnect tries + * @max_reconnect_attempts: Number of times to reconnect on error before giving + * up, 0 for * disabled, -1 for forever + * @nr_poll_queues: number of polling mode connection using IB_POLL_DIRECT flag + * + * Starts session establishment with the rtrs_server. The function can block + * up to ~2000ms before it returns. + * + * Return a valid pointer on success otherwise PTR_ERR. + */ +struct rtrs_clt_sess *rtrs_clt_open(struct rtrs_clt_ops *ops, + const char *pathname, + const struct rtrs_addr *paths, + size_t paths_num, u16 port, + size_t pdu_sz, u8 reconnect_delay_sec, + s16 max_reconnect_attempts, u32 nr_poll_queues) +{ + struct rtrs_clt_path *clt_path, *tmp; + struct rtrs_clt_sess *clt; + int err, i; + + if (strchr(pathname, '/') || strchr(pathname, '.')) { + pr_err("pathname cannot contain / and .\n"); + err = -EINVAL; + goto out; + } + + clt = alloc_clt(pathname, paths_num, port, pdu_sz, ops->priv, + ops->link_ev, + 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_path *clt_path; + + clt_path = alloc_path(clt, &paths[i], nr_cpu_ids, + nr_poll_queues); + if (IS_ERR(clt_path)) { + err = PTR_ERR(clt_path); + goto close_all_path; + } + if (!i) + clt_path->for_new_clt = 1; + list_add_tail_rcu(&clt_path->s.entry, &clt->paths_list); + + err = init_path(clt_path); + if (err) { + list_del_rcu(&clt_path->s.entry); + rtrs_clt_close_conns(clt_path, true); + free_percpu(clt_path->stats->pcpu_stats); + kfree(clt_path->stats); + free_path(clt_path); + goto close_all_path; + } + + err = rtrs_clt_create_path_files(clt_path); + if (err) { + list_del_rcu(&clt_path->s.entry); + rtrs_clt_close_conns(clt_path, true); + free_percpu(clt_path->stats->pcpu_stats); + kfree(clt_path->stats); + free_path(clt_path); + goto close_all_path; + } + } + err = alloc_permits(clt); + if (err) + goto close_all_path; + + return clt; + +close_all_path: + list_for_each_entry_safe(clt_path, tmp, &clt->paths_list, s.entry) { + rtrs_clt_destroy_path_files(clt_path, NULL); + rtrs_clt_close_conns(clt_path, true); + kobject_put(&clt_path->kobj); + } + rtrs_clt_destroy_sysfs_root(clt); + free_clt(clt); + +out: + return ERR_PTR(err); +} +EXPORT_SYMBOL(rtrs_clt_open); + +/** + * rtrs_clt_close() - Close a path + * @clt: Session handle. Session is freed upon return. + */ +void rtrs_clt_close(struct rtrs_clt_sess *clt) +{ + struct rtrs_clt_path *clt_path, *tmp; + + /* Firstly forbid sysfs access */ + rtrs_clt_destroy_sysfs_root(clt); + + /* Now it is safe to iterate over all paths without locks */ + list_for_each_entry_safe(clt_path, tmp, &clt->paths_list, s.entry) { + rtrs_clt_close_conns(clt_path, true); + rtrs_clt_destroy_path_files(clt_path, NULL); + kobject_put(&clt_path->kobj); + } + free_permits(clt); + free_clt(clt); +} +EXPORT_SYMBOL(rtrs_clt_close); + +int rtrs_clt_reconnect_from_sysfs(struct rtrs_clt_path *clt_path) +{ + enum rtrs_clt_state old_state; + int err = -EBUSY; + bool changed; + + changed = rtrs_clt_change_state_get_old(clt_path, + RTRS_CLT_RECONNECTING, + &old_state); + if (changed) { + clt_path->reconnect_attempts = 0; + rtrs_clt_stop_and_destroy_conns(clt_path); + queue_delayed_work(rtrs_wq, &clt_path->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(&clt_path->reconnect_dwork); + err = (READ_ONCE(clt_path->state) == + RTRS_CLT_CONNECTED ? 0 : -ENOTCONN); + } + + return err; +} + +int rtrs_clt_remove_path_from_sysfs(struct rtrs_clt_path *clt_path, + const struct attribute *sysfs_self) +{ + enum rtrs_clt_state old_state; + bool changed; + + /* + * 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(clt_path, true); + changed = rtrs_clt_change_state_get_old(clt_path, + RTRS_CLT_DEAD, + &old_state); + } while (!changed && old_state != RTRS_CLT_DEAD); + + if (changed) { + rtrs_clt_remove_path_from_arr(clt_path); + rtrs_clt_destroy_path_files(clt_path, sysfs_self); + kobject_put(&clt_path->kobj); + } + + return 0; +} + +void rtrs_clt_set_max_reconnect_attempts(struct rtrs_clt_sess *clt, int value) +{ + clt->max_reconnect_attempts = (unsigned int)value; +} + +int rtrs_clt_get_max_reconnect_attempts(const struct rtrs_clt_sess *clt) +{ + return (int)clt->max_reconnect_attempts; +} + +/** + * rtrs_clt_request() - Request data transfer to/from server via RDMA. + * + * @dir: READ/WRITE + * @ops: callback function to be called as confirmation, and the pointer. + * @clt: Session + * @permit: Preallocated permit + * @vec: Message that is sent to server together with the request. + * Sum of len of all @vec elements limited to <= IO_MSG_SIZE. + * Since the msg is copied internally it can be allocated on stack. + * @nr: Number of elements in @vec. + * @data_len: length of data sent to/from server + * @sg: Pages to be sent/received to/from server. + * @sg_cnt: Number of elements in the @sg + * + * Return: + * 0: Success + * <0: Error + * + * On dir=READ rtrs client will request a data transfer from Server to client. + * The data that the server will respond with will be stored in @sg when + * the user receives an %RTRS_CLT_RDMA_EV_RDMA_REQUEST_WRITE_COMPL event. + * On dir=WRITE rtrs client will rdma write data in sg to server side. + */ +int rtrs_clt_request(int dir, struct rtrs_clt_req_ops *ops, + struct rtrs_clt_sess *clt, struct rtrs_permit *permit, + 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_path *clt_path; + + 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; + } + + rcu_read_lock(); + for (path_it_init(&it, clt); + (clt_path = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) { + if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED) + continue; + + if (usr_len + hdr_len > clt_path->max_hdr_size) { + rtrs_wrn_rl(clt_path->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, clt_path->max_hdr_size); + err = -EMSGSIZE; + break; + } + req = rtrs_clt_get_req(clt_path, ops->conf_fn, permit, ops->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 (err) { + req->in_use = false; + continue; + } + /* Success path */ + break; + } + path_it_deinit(&it); + rcu_read_unlock(); + + return err; +} +EXPORT_SYMBOL(rtrs_clt_request); + +int rtrs_clt_rdma_cq_direct(struct rtrs_clt_sess *clt, unsigned int index) +{ + /* If no path, return -1 for block layer not to try again */ + int cnt = -1; + struct rtrs_con *con; + struct rtrs_clt_path *clt_path; + struct path_it it; + + rcu_read_lock(); + for (path_it_init(&it, clt); + (clt_path = it.next_path(&it)) && it.i < it.clt->paths_num; it.i++) { + if (READ_ONCE(clt_path->state) != RTRS_CLT_CONNECTED) + continue; + + con = clt_path->s.con[index + 1]; + cnt = ib_process_cq_direct(con->cq, -1); + if (cnt) + break; + } + path_it_deinit(&it); + rcu_read_unlock(); + + return cnt; +} +EXPORT_SYMBOL(rtrs_clt_rdma_cq_direct); + +/** + * rtrs_clt_query() - queries RTRS session attributes + *@clt: session pointer + *@attr: query results for session attributes. + * Returns: + * 0 on success + * -ECOMM no connection to the server + */ +int rtrs_clt_query(struct rtrs_clt_sess *clt, struct rtrs_attrs *attr) +{ + if (!rtrs_clt_is_connected(clt)) + return -ECOMM; + + attr->queue_depth = clt->queue_depth; + attr->max_segments = clt->max_segments; + /* Cap max_io_size to min of remote buffer size and the fr pages */ + attr->max_io_size = min_t(int, clt->max_io_size, + clt->max_segments * SZ_4K); + + return 0; +} +EXPORT_SYMBOL(rtrs_clt_query); + +int rtrs_clt_create_path_from_sysfs(struct rtrs_clt_sess *clt, + struct rtrs_addr *addr) +{ + struct rtrs_clt_path *clt_path; + int err; + + clt_path = alloc_path(clt, addr, nr_cpu_ids, 0); + if (IS_ERR(clt_path)) + return PTR_ERR(clt_path); + + mutex_lock(&clt->paths_mutex); + if (clt->paths_num == 0) { + /* + * When all the paths are removed for a session, + * the addition of the first path is like a new session for + * the storage server + */ + clt_path->for_new_clt = 1; + } + + mutex_unlock(&clt->paths_mutex); + + /* + * 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(clt_path); + + err = init_path(clt_path); + if (err) + goto close_path; + + err = rtrs_clt_create_path_files(clt_path); + if (err) + goto close_path; + + return 0; + +close_path: + rtrs_clt_remove_path_from_arr(clt_path); + rtrs_clt_close_conns(clt_path, true); + free_percpu(clt_path->stats->pcpu_stats); + kfree(clt_path->stats); + free_path(clt_path); + + return err; +} + +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_rdma_dev_pd_ops dev_pd_ops = { + .init = rtrs_clt_ib_dev_init +}; + +static int __init rtrs_client_init(void) +{ + rtrs_rdma_dev_pd_init(0, &dev_pd); + + rtrs_clt_dev_class = class_create(THIS_MODULE, "rtrs-client"); + if (IS_ERR(rtrs_clt_dev_class)) { + pr_err("Failed to create rtrs-client dev class\n"); + return PTR_ERR(rtrs_clt_dev_class); + } + rtrs_wq = alloc_workqueue("rtrs_client_wq", 0, 0); + if (!rtrs_wq) { + class_destroy(rtrs_clt_dev_class); + return -ENOMEM; + } + + return 0; +} + +static void __exit rtrs_client_exit(void) +{ + destroy_workqueue(rtrs_wq); + class_destroy(rtrs_clt_dev_class); + rtrs_rdma_dev_pd_deinit(&dev_pd); +} + +module_init(rtrs_client_init); +module_exit(rtrs_client_exit); |