// SPDX-License-Identifier: GPL-2.0-only
/*
* RDMA transport layer based on the trans_fd.c implementation.
*
* Copyright (C) 2008 by Tom Tucker <[email protected]>
* Copyright (C) 2006 by Russ Cox <[email protected]>
* Copyright (C) 2004-2005 by Latchesar Ionkov <[email protected]>
* Copyright (C) 2004-2008 by Eric Van Hensbergen <[email protected]>
* Copyright (C) 1997-2002 by Ron Minnich <[email protected]>
*/
#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/file.h>
#include <linux/parser.h>
#include <linux/semaphore.h>
#include <linux/slab.h>
#include <linux/seq_file.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
* @timeout: Number of uSecs to wait for connection management events
* @privport: Whether a privileged port may be used
* @port: The port to use
* @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;
long timeout;
bool privport;
u16 port;
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;
};
struct p9_rdma_req;
/**
* struct p9_rdma_context - Keeps track of in-process WR
*
* @cqe: completion queue entry
* @busa: Bus address to unmap when the WR completes
* @req: Keeps track of requests (send)
* @rc: Keepts track of replies (receive)
*/
struct p9_rdma_context {
struct ib_cqe cqe;
dma_addr_t busa;
union {
struct p9_req_t *req;
struct p9_fcall rc;
};
};
/**
* struct p9_rdma_opts - Collection of mount options
* @port: port of connection
* @privport: Whether a privileged port may be used
* @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;
bool privport;
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,
/* Options that take no argument */
Opt_privport,
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_privport, "privport"},
{Opt_err, NULL},
};
static int p9_rdma_show_options(struct seq_file *m, struct p9_client *clnt)
{
struct p9_trans_rdma *rdma = clnt->trans;
if (rdma->port != P9_PORT)
seq_printf(m, ",port=%u", rdma->port);
if (rdma->sq_depth != P9_RDMA_SQ_DEPTH)
seq_printf(m, ",sq=%u", rdma->sq_depth);
if (rdma->rq_depth != P9_RDMA_RQ_DEPTH)
seq_printf(m, ",rq=%u", rdma->rq_depth);
if (rdma->timeout != P9_RDMA_TIMEOUT)
seq_printf(m, ",timeout=%lu", rdma->timeout);
if (rdma->privport)
seq_puts(m, ",privport");
return 0;
}
/**
* 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;
opts->privport = false;
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) && (token != Opt_privport)) {
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;
case Opt_privport:
opts->privport = true;
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;
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
recv_done(struct ib_cq *cq, struct ib_wc *wc)
{
struct p9_client *client = cq->cq_context;
struct p9_trans_rdma *rdma = client->trans;
struct p9_rdma_context *c =
container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
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 (wc->status != IB_WC_SUCCESS)
goto err_out;
c->rc.size = wc->byte_len;
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.sdata)) {
pr_err("Duplicate reply for request %d", tag);
goto err_out;
}
req->rc.size = c->rc.size;
req->rc.sdata = c->rc.sdata;
p9_client_cb(client, req, REQ_STATUS_RCVD);
out:
up(&rdma->rq_sem);
kfree(c);
return;
err_out:
p9_debug(P9_DEBUG_ERROR, "req %p err %d status %d\n",
req, err, wc->status);
rdma->state = P9_RDMA_FLUSHING;
client->status = Disconnected;
goto out;
}
static void
send_done(struct ib_cq *cq, struct ib_wc *wc)
{
struct p9_client *client = cq->cq_context;
struct p9_trans_rdma *rdma = client->trans;
struct p9_rdma_context *c =
container_of(wc->wr_cqe, struct p9_rdma_context, cqe);
ib_dma_unmap_single(rdma->cm_id->device,
c->busa, c->req->tc.size,
DMA_TO_DEVICE);
up(&rdma->sq_sem);
p9_req_put(client, c->req);
kfree(c);
}
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 rdma_destroy_trans(struct p9_trans_rdma *rdma)
{
if (!rdma)
return;
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_free_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;
struct ib_sge sge;
int ret;
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;
c->cqe.done = recv_done;
sge.addr = c->busa;
sge.length = client->msize;
sge.lkey = rdma->pd->local_dma_lkey;
wr.next = NULL;
wr.wr_cqe = &c->cqe;
wr.sg_list = &sge;
wr.num_sge = 1;
ret = ib_post_recv(rdma->qp, &wr, NULL);
if (ret)
ib_dma_unmap_single(rdma->cm_id->device, c->busa,
client->msize, DMA_FROM_DEVICE);
return ret;
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;
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! */
p9_fcall_fini(&req->rc);
req->rc.sdata = 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.sdata = req->rc.sdata;
/*
* 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_ERROR, "POST RECV failed: %d\n", err);
goto recv_error;
}
/* remove posted receive buffer from request structure */
req->rc.sdata = 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;
}
c->cqe.done = send_done;
sge.addr = c->busa;
sge.length = c->req->tc.size;
sge.lkey = rdma->pd->local_dma_lkey;
wr.next = NULL;
wr.wr_cqe = &c->cqe;
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 dma_unmap;
}
/* 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.
*/
WRITE_ONCE(req->status, REQ_STATUS_SENT);
err = ib_post_send(rdma->qp, &wr, NULL);
if (err)
goto dma_unmap;
/* Success */
return 0;
dma_unmap:
ib_dma_unmap_single(rdma->cm_id->device, c->busa,
c->req->tc.size, DMA_TO_DEVICE);
/* Handle errors that happened during or while preparing the send: */
send_error:
WRITE_ONCE(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 (err != -EINTR && 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->port = opts->port;
rdma->privport = opts->privport;
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;
}
static int p9_rdma_bind_privport(struct p9_trans_rdma *rdma)
{
struct sockaddr_in cl = {
.sin_family = AF_INET,
.sin_addr.s_addr = htonl(INADDR_ANY),
};
int port, err = -EINVAL;
for (port = P9_DEF_MAX_RESVPORT; port >= P9_DEF_MIN_RESVPORT; port--) {
cl.sin_port = htons((ushort)port);
err = rdma_bind_addr(rdma->cm_id, (struct sockaddr *)&cl);
if (err != -EADDRINUSE)
break;
}
return err;
}
/**
* rdma_create_trans - Transport method for creating a transport 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;
if (addr == NULL)
return -EINVAL;
/* 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(&init_net, 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;
/* Bind to a privileged port if we need to */
if (opts.privport) {
err = p9_rdma_bind_privport(rdma);
if (err < 0) {
pr_err("%s (%d): problem binding to privport: %d\n",
__func__, task_pid_nr(current), -err);
goto error;
}
}
/* 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;
/* Create the Completion Queue */
rdma->cq = ib_alloc_cq_any(rdma->cm_id->device, client,
opts.sq_depth + opts.rq_depth + 1,
IB_POLL_SOFTIRQ);
if (IS_ERR(rdma->cq))
goto error;
/* Create the Protection Domain */
rdma->pd = ib_alloc_pd(rdma->cm_id->device, 0);
if (IS_ERR(rdma->pd))
goto error;
/* 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,
.pooled_rbuffers = true,
.def = 0,
.owner = THIS_MODULE,
.create = rdma_create_trans,
.close = rdma_close,
.request = rdma_request,
.cancel = rdma_cancel,
.cancelled = rdma_cancelled,
.show_options = p9_rdma_show_options,
};
/**
* 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_ALIAS_9P("rdma");
MODULE_AUTHOR("Tom Tucker <[email protected]>");
MODULE_DESCRIPTION("RDMA Transport for 9P");
MODULE_LICENSE("Dual BSD/GPL");
Codebase Browser
linux