/* * linux/fs/9p/trans_rdma.c * * RDMA transport layer based on the trans_fd.c implementation. * * Copyright (C) 2008 by Tom Tucker <tom@opengridcomputing.com> * Copyright (C) 2006 by Russ Cox <rsc@swtch.com> * Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net> * Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com> * Copyright (C) 1997-2002 by Ron Minnich <rminnich@sarnoff.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to: * Free Software Foundation * 51 Franklin Street, Fifth Floor * Boston, MA 02111-1301 USA * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/in.h> #include <linux/module.h> #include <linux/net.h> #include <linux/ipv6.h> #include <linux/kthread.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/un.h> #include <linux/uaccess.h> #include <linux/inet.h> #include <linux/idr.h> #include <linux/file.h> #include <linux/parser.h> #include <linux/semaphore.h> #include <linux/slab.h> #include <net/9p/9p.h> #include <net/9p/client.h> #include <net/9p/transport.h> #include <rdma/ib_verbs.h> #include <rdma/rdma_cm.h> #define P9_PORT 5640 #define P9_RDMA_SQ_DEPTH 32 #define P9_RDMA_RQ_DEPTH 32 #define P9_RDMA_SEND_SGE 4 #define P9_RDMA_RECV_SGE 4 #define P9_RDMA_IRD 0 #define P9_RDMA_ORD 0 #define P9_RDMA_TIMEOUT 30000 /* 30 seconds */ #define P9_RDMA_MAXSIZE (1024*1024) /* 1MB */ /** * struct p9_trans_rdma - RDMA transport instance * * @state: tracks the transport state machine for connection setup and tear down * @cm_id: The RDMA CM ID * @pd: Protection Domain pointer * @qp: Queue Pair pointer * @cq: Completion Queue pointer * @dm_mr: DMA Memory Region pointer * @lkey: The local access only memory region key * @timeout: Number of uSecs to wait for connection management events * @sq_depth: The depth of the Send Queue * @sq_sem: Semaphore for the SQ * @rq_depth: The depth of the Receive Queue. * @rq_sem: Semaphore for the RQ * @excess_rc : Amount of posted Receive Contexts without a pending request. * See rdma_request() * @addr: The remote peer's address * @req_lock: Protects the active request list * @cm_done: Completion event for connection management tracking */ struct p9_trans_rdma { enum { P9_RDMA_INIT, P9_RDMA_ADDR_RESOLVED, P9_RDMA_ROUTE_RESOLVED, P9_RDMA_CONNECTED, P9_RDMA_FLUSHING, P9_RDMA_CLOSING, P9_RDMA_CLOSED, } state; struct rdma_cm_id *cm_id; struct ib_pd *pd; struct ib_qp *qp; struct ib_cq *cq; struct ib_mr *dma_mr; u32 lkey; long timeout; int sq_depth; struct semaphore sq_sem; int rq_depth; struct semaphore rq_sem; atomic_t excess_rc; struct sockaddr_in addr; spinlock_t req_lock; struct completion cm_done; }; /** * p9_rdma_context - Keeps track of in-process WR * * @wc_op: The original WR op for when the CQE completes in error. * @busa: Bus address to unmap when the WR completes * @req: Keeps track of requests (send) * @rc: Keepts track of replies (receive) */ struct p9_rdma_req; struct p9_rdma_context { enum ib_wc_opcode wc_op; dma_addr_t busa; union { struct p9_req_t *req; struct p9_fcall *rc; }; }; /** * p9_rdma_opts - Collection of mount options * @port: port of connection * @sq_depth: The requested depth of the SQ. This really doesn't need * to be any deeper than the number of threads used in the client * @rq_depth: The depth of the RQ. Should be greater than or equal to SQ depth * @timeout: Time to wait in msecs for CM events */ struct p9_rdma_opts { short port; int sq_depth; int rq_depth; long timeout; }; /* * Option Parsing (code inspired by NFS code) */ enum { /* Options that take integer arguments */ Opt_port, Opt_rq_depth, Opt_sq_depth, Opt_timeout, Opt_err, }; static match_table_t tokens = { {Opt_port, "port=%u"}, {Opt_sq_depth, "sq=%u"}, {Opt_rq_depth, "rq=%u"}, {Opt_timeout, "timeout=%u"}, {Opt_err, NULL}, }; /** * parse_opts - parse mount options into rdma options structure * @params: options string passed from mount * @opts: rdma transport-specific structure to parse options into * * Returns 0 upon success, -ERRNO upon failure */ static int parse_opts(char *params, struct p9_rdma_opts *opts) { char *p; substring_t args[MAX_OPT_ARGS]; int option; char *options, *tmp_options; opts->port = P9_PORT; opts->sq_depth = P9_RDMA_SQ_DEPTH; opts->rq_depth = P9_RDMA_RQ_DEPTH; opts->timeout = P9_RDMA_TIMEOUT; if (!params) return 0; tmp_options = kstrdup(params, GFP_KERNEL); if (!tmp_options) { p9_debug(P9_DEBUG_ERROR, "failed to allocate copy of option string\n"); return -ENOMEM; } options = tmp_options; while ((p = strsep(&options, ",")) != NULL) { int token; int r; if (!*p) continue; token = match_token(p, tokens, args); if (token == Opt_err) continue; r = match_int(&args[0], &option); if (r < 0) { p9_debug(P9_DEBUG_ERROR, "integer field, but no integer?\n"); continue; } switch (token) { case Opt_port: opts->port = option; break; case Opt_sq_depth: opts->sq_depth = option; break; case Opt_rq_depth: opts->rq_depth = option; break; case Opt_timeout: opts->timeout = option; break; default: continue; } } /* RQ must be at least as large as the SQ */ opts->rq_depth = max(opts->rq_depth, opts->sq_depth); kfree(tmp_options); return 0; } static int p9_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event) { struct p9_client *c = id->context; struct p9_trans_rdma *rdma = c->trans; switch (event->event) { case RDMA_CM_EVENT_ADDR_RESOLVED: BUG_ON(rdma->state != P9_RDMA_INIT); rdma->state = P9_RDMA_ADDR_RESOLVED; break; case RDMA_CM_EVENT_ROUTE_RESOLVED: BUG_ON(rdma->state != P9_RDMA_ADDR_RESOLVED); rdma->state = P9_RDMA_ROUTE_RESOLVED; break; case RDMA_CM_EVENT_ESTABLISHED: BUG_ON(rdma->state != P9_RDMA_ROUTE_RESOLVED); rdma->state = P9_RDMA_CONNECTED; break; case RDMA_CM_EVENT_DISCONNECTED: if (rdma) rdma->state = P9_RDMA_CLOSED; if (c) c->status = Disconnected; break; case RDMA_CM_EVENT_TIMEWAIT_EXIT: break; case RDMA_CM_EVENT_ADDR_CHANGE: case RDMA_CM_EVENT_ROUTE_ERROR: case RDMA_CM_EVENT_DEVICE_REMOVAL: case RDMA_CM_EVENT_MULTICAST_JOIN: case RDMA_CM_EVENT_MULTICAST_ERROR: case RDMA_CM_EVENT_REJECTED: case RDMA_CM_EVENT_CONNECT_REQUEST: case RDMA_CM_EVENT_CONNECT_RESPONSE: case RDMA_CM_EVENT_CONNECT_ERROR: case RDMA_CM_EVENT_ADDR_ERROR: case RDMA_CM_EVENT_UNREACHABLE: c->status = Disconnected; rdma_disconnect(rdma->cm_id); break; default: BUG(); } complete(&rdma->cm_done); return 0; } static void handle_recv(struct p9_client *client, struct p9_trans_rdma *rdma, struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len) { struct p9_req_t *req; int err = 0; int16_t tag; req = NULL; ib_dma_unmap_single(rdma->cm_id->device, c->busa, client->msize, DMA_FROM_DEVICE); if (status != IB_WC_SUCCESS) goto err_out; err = p9_parse_header(c->rc, NULL, NULL, &tag, 1); if (err) goto err_out; req = p9_tag_lookup(client, tag); if (!req) goto err_out; /* Check that we have not yet received a reply for this request. */ if (unlikely(req->rc)) { pr_err("Duplicate reply for request %d", tag); goto err_out; } req->rc = c->rc; p9_client_cb(client, req, REQ_STATUS_RCVD); return; err_out: p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n", req, err, status); rdma->state = P9_RDMA_FLUSHING; client->status = Disconnected; } static void handle_send(struct p9_client *client, struct p9_trans_rdma *rdma, struct p9_rdma_context *c, enum ib_wc_status status, u32 byte_len) { ib_dma_unmap_single(rdma->cm_id->device, c->busa, c->req->tc->size, DMA_TO_DEVICE); } static void qp_event_handler(struct ib_event *event, void *context) { p9_debug(P9_DEBUG_ERROR, "QP event %d context %p\n", event->event, context); } static void cq_comp_handler(struct ib_cq *cq, void *cq_context) { struct p9_client *client = cq_context; struct p9_trans_rdma *rdma = client->trans; int ret; struct ib_wc wc; ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP); while ((ret = ib_poll_cq(cq, 1, &wc)) > 0) { struct p9_rdma_context *c = (void *) (unsigned long) wc.wr_id; switch (c->wc_op) { case IB_WC_RECV: handle_recv(client, rdma, c, wc.status, wc.byte_len); up(&rdma->rq_sem); break; case IB_WC_SEND: handle_send(client, rdma, c, wc.status, wc.byte_len); up(&rdma->sq_sem); break; default: pr_err("unexpected completion type, c->wc_op=%d, wc.opcode=%d, status=%d\n", c->wc_op, wc.opcode, wc.status); break; } kfree(c); } } static void cq_event_handler(struct ib_event *e, void *v) { p9_debug(P9_DEBUG_ERROR, "CQ event %d context %p\n", e->event, v); } static void rdma_destroy_trans(struct p9_trans_rdma *rdma) { if (!rdma) return; if (rdma->dma_mr && !IS_ERR(rdma->dma_mr)) ib_dereg_mr(rdma->dma_mr); if (rdma->qp && !IS_ERR(rdma->qp)) ib_destroy_qp(rdma->qp); if (rdma->pd && !IS_ERR(rdma->pd)) ib_dealloc_pd(rdma->pd); if (rdma->cq && !IS_ERR(rdma->cq)) ib_destroy_cq(rdma->cq); if (rdma->cm_id && !IS_ERR(rdma->cm_id)) rdma_destroy_id(rdma->cm_id); kfree(rdma); } static int post_recv(struct p9_client *client, struct p9_rdma_context *c) { struct p9_trans_rdma *rdma = client->trans; struct ib_recv_wr wr, *bad_wr; struct ib_sge sge; c->busa = ib_dma_map_single(rdma->cm_id->device, c->rc->sdata, client->msize, DMA_FROM_DEVICE); if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) goto error; sge.addr = c->busa; sge.length = client->msize; sge.lkey = rdma->lkey; wr.next = NULL; c->wc_op = IB_WC_RECV; wr.wr_id = (unsigned long) c; wr.sg_list = &sge; wr.num_sge = 1; return ib_post_recv(rdma->qp, &wr, &bad_wr); error: p9_debug(P9_DEBUG_ERROR, "EIO\n"); return -EIO; } static int rdma_request(struct p9_client *client, struct p9_req_t *req) { struct p9_trans_rdma *rdma = client->trans; struct ib_send_wr wr, *bad_wr; struct ib_sge sge; int err = 0; unsigned long flags; struct p9_rdma_context *c = NULL; struct p9_rdma_context *rpl_context = NULL; /* When an error occurs between posting the recv and the send, * there will be a receive context posted without a pending request. * Since there is no way to "un-post" it, we remember it and skip * post_recv() for the next request. * So here, * see if we are this `next request' and need to absorb an excess rc. * If yes, then drop and free our own, and do not recv_post(). **/ if (unlikely(atomic_read(&rdma->excess_rc) > 0)) { if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) { /* Got one ! */ kfree(req->rc); req->rc = NULL; goto dont_need_post_recv; } else { /* We raced and lost. */ atomic_inc(&rdma->excess_rc); } } /* Allocate an fcall for the reply */ rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS); if (!rpl_context) { err = -ENOMEM; goto recv_error; } rpl_context->rc = req->rc; /* * Post a receive buffer for this request. We need to ensure * there is a reply buffer available for every outstanding * request. A flushed request can result in no reply for an * outstanding request, so we must keep a count to avoid * overflowing the RQ. */ if (down_interruptible(&rdma->rq_sem)) { err = -EINTR; goto recv_error; } err = post_recv(client, rpl_context); if (err) { p9_debug(P9_DEBUG_FCALL, "POST RECV failed\n"); goto recv_error; } /* remove posted receive buffer from request structure */ req->rc = NULL; dont_need_post_recv: /* Post the request */ c = kmalloc(sizeof *c, GFP_NOFS); if (!c) { err = -ENOMEM; goto send_error; } c->req = req; c->busa = ib_dma_map_single(rdma->cm_id->device, c->req->tc->sdata, c->req->tc->size, DMA_TO_DEVICE); if (ib_dma_mapping_error(rdma->cm_id->device, c->busa)) { err = -EIO; goto send_error; } sge.addr = c->busa; sge.length = c->req->tc->size; sge.lkey = rdma->lkey; wr.next = NULL; c->wc_op = IB_WC_SEND; wr.wr_id = (unsigned long) c; wr.opcode = IB_WR_SEND; wr.send_flags = IB_SEND_SIGNALED; wr.sg_list = &sge; wr.num_sge = 1; if (down_interruptible(&rdma->sq_sem)) { err = -EINTR; goto send_error; } /* Mark request as `sent' *before* we actually send it, * because doing if after could erase the REQ_STATUS_RCVD * status in case of a very fast reply. */ req->status = REQ_STATUS_SENT; err = ib_post_send(rdma->qp, &wr, &bad_wr); if (err) goto send_error; /* Success */ return 0; /* Handle errors that happened during or while preparing the send: */ send_error: req->status = REQ_STATUS_ERROR; kfree(c); p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err); /* Ach. * We did recv_post(), but not send. We have one recv_post in excess. */ atomic_inc(&rdma->excess_rc); return err; /* Handle errors that happened during or while preparing post_recv(): */ recv_error: kfree(rpl_context); spin_lock_irqsave(&rdma->req_lock, flags); if (rdma->state < P9_RDMA_CLOSING) { rdma->state = P9_RDMA_CLOSING; spin_unlock_irqrestore(&rdma->req_lock, flags); rdma_disconnect(rdma->cm_id); } else spin_unlock_irqrestore(&rdma->req_lock, flags); return err; } static void rdma_close(struct p9_client *client) { struct p9_trans_rdma *rdma; if (!client) return; rdma = client->trans; if (!rdma) return; client->status = Disconnected; rdma_disconnect(rdma->cm_id); rdma_destroy_trans(rdma); } /** * alloc_rdma - Allocate and initialize the rdma transport structure * @opts: Mount options structure */ static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts) { struct p9_trans_rdma *rdma; rdma = kzalloc(sizeof(struct p9_trans_rdma), GFP_KERNEL); if (!rdma) return NULL; rdma->sq_depth = opts->sq_depth; rdma->rq_depth = opts->rq_depth; rdma->timeout = opts->timeout; spin_lock_init(&rdma->req_lock); init_completion(&rdma->cm_done); sema_init(&rdma->sq_sem, rdma->sq_depth); sema_init(&rdma->rq_sem, rdma->rq_depth); atomic_set(&rdma->excess_rc, 0); return rdma; } static int rdma_cancel(struct p9_client *client, struct p9_req_t *req) { /* Nothing to do here. * We will take care of it (if we have to) in rdma_cancelled() */ return 1; } /* A request has been fully flushed without a reply. * That means we have posted one buffer in excess. */ static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req) { struct p9_trans_rdma *rdma = client->trans; atomic_inc(&rdma->excess_rc); return 0; } /** * trans_create_rdma - Transport method for creating atransport instance * @client: client instance * @addr: IP address string * @args: Mount options string */ static int rdma_create_trans(struct p9_client *client, const char *addr, char *args) { int err; struct p9_rdma_opts opts; struct p9_trans_rdma *rdma; struct rdma_conn_param conn_param; struct ib_qp_init_attr qp_attr; struct ib_device_attr devattr; /* Parse the transport specific mount options */ err = parse_opts(args, &opts); if (err < 0) return err; /* Create and initialize the RDMA transport structure */ rdma = alloc_rdma(&opts); if (!rdma) return -ENOMEM; /* Create the RDMA CM ID */ rdma->cm_id = rdma_create_id(p9_cm_event_handler, client, RDMA_PS_TCP, IB_QPT_RC); if (IS_ERR(rdma->cm_id)) goto error; /* Associate the client with the transport */ client->trans = rdma; /* Resolve the server's address */ rdma->addr.sin_family = AF_INET; rdma->addr.sin_addr.s_addr = in_aton(addr); rdma->addr.sin_port = htons(opts.port); err = rdma_resolve_addr(rdma->cm_id, NULL, (struct sockaddr *)&rdma->addr, rdma->timeout); if (err) goto error; err = wait_for_completion_interruptible(&rdma->cm_done); if (err || (rdma->state != P9_RDMA_ADDR_RESOLVED)) goto error; /* Resolve the route to the server */ err = rdma_resolve_route(rdma->cm_id, rdma->timeout); if (err) goto error; err = wait_for_completion_interruptible(&rdma->cm_done); if (err || (rdma->state != P9_RDMA_ROUTE_RESOLVED)) goto error; /* Query the device attributes */ err = ib_query_device(rdma->cm_id->device, &devattr); if (err) goto error; /* Create the Completion Queue */ rdma->cq = ib_create_cq(rdma->cm_id->device, cq_comp_handler, cq_event_handler, client, opts.sq_depth + opts.rq_depth + 1, 0); if (IS_ERR(rdma->cq)) goto error; ib_req_notify_cq(rdma->cq, IB_CQ_NEXT_COMP); /* Create the Protection Domain */ rdma->pd = ib_alloc_pd(rdma->cm_id->device); if (IS_ERR(rdma->pd)) goto error; /* Cache the DMA lkey in the transport */ rdma->dma_mr = NULL; if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY) rdma->lkey = rdma->cm_id->device->local_dma_lkey; else { rdma->dma_mr = ib_get_dma_mr(rdma->pd, IB_ACCESS_LOCAL_WRITE); if (IS_ERR(rdma->dma_mr)) goto error; rdma->lkey = rdma->dma_mr->lkey; } /* Create the Queue Pair */ memset(&qp_attr, 0, sizeof qp_attr); qp_attr.event_handler = qp_event_handler; qp_attr.qp_context = client; qp_attr.cap.max_send_wr = opts.sq_depth; qp_attr.cap.max_recv_wr = opts.rq_depth; qp_attr.cap.max_send_sge = P9_RDMA_SEND_SGE; qp_attr.cap.max_recv_sge = P9_RDMA_RECV_SGE; qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR; qp_attr.qp_type = IB_QPT_RC; qp_attr.send_cq = rdma->cq; qp_attr.recv_cq = rdma->cq; err = rdma_create_qp(rdma->cm_id, rdma->pd, &qp_attr); if (err) goto error; rdma->qp = rdma->cm_id->qp; /* Request a connection */ memset(&conn_param, 0, sizeof(conn_param)); conn_param.private_data = NULL; conn_param.private_data_len = 0; conn_param.responder_resources = P9_RDMA_IRD; conn_param.initiator_depth = P9_RDMA_ORD; err = rdma_connect(rdma->cm_id, &conn_param); if (err) goto error; err = wait_for_completion_interruptible(&rdma->cm_done); if (err || (rdma->state != P9_RDMA_CONNECTED)) goto error; client->status = Connected; return 0; error: rdma_destroy_trans(rdma); return -ENOTCONN; } static struct p9_trans_module p9_rdma_trans = { .name = "rdma", .maxsize = P9_RDMA_MAXSIZE, .def = 0, .owner = THIS_MODULE, .create = rdma_create_trans, .close = rdma_close, .request = rdma_request, .cancel = rdma_cancel, .cancelled = rdma_cancelled, }; /** * p9_trans_rdma_init - Register the 9P RDMA transport driver */ static int __init p9_trans_rdma_init(void) { v9fs_register_trans(&p9_rdma_trans); return 0; } static void __exit p9_trans_rdma_exit(void) { v9fs_unregister_trans(&p9_rdma_trans); } module_init(p9_trans_rdma_init); module_exit(p9_trans_rdma_exit); MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>"); MODULE_DESCRIPTION("RDMA Transport for 9P"); MODULE_LICENSE("Dual BSD/GPL");