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9p: rdma: RDMA Transport Support for 9P

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This patch implements the RDMA transport provider for 9P. It allows
mounts to be performed over iWARP and IB capable network interfaces.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: Latchesar Ionkov <lionkov@lanl.gov>
This commit is contained in:
Tom Tucker 2008-10-22 18:47:39 -05:00 committed by Eric Van Hensbergen
parent ea2e7996fc
commit fc79d4b104
4 changed files with 723 additions and 0 deletions
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1
include/net/9p/client.h
View File

@ -206,6 +206,7 @@ int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
void p9_client_cb(struct p9_client *c, struct p9_req_t *req);
int p9_parse_header(struct p9_fcall *, int32_t *, int8_t *, int16_t *, int);
int p9stat_read(char *, int, struct p9_wstat *, int);
void p9stat_free(struct p9_wstat *);

6
net/9p/Kconfig
View File

@ -20,6 +20,12 @@ config NET_9P_VIRTIO
This builds support for a transports between
guest partitions and a host partition.
config NET_9P_RDMA
depends on NET_9P && INFINIBAND && EXPERIMENTAL
tristate "9P RDMA Transport (Experimental)"
help
This builds support for a RDMA transport.
config NET_9P_DEBUG
bool "Debug information"
depends on NET_9P

4
net/9p/Makefile
View File

@ -1,5 +1,6 @@
obj-$(CONFIG_NET_9P) := 9pnet.o
obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o
9pnet-objs := \
mod.o \
@ -11,3 +12,6 @@ obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
9pnet_virtio-objs := \
trans_virtio.o \
9pnet_rdma-objs := \
trans_rdma.o \

712
net/9p/trans_rdma.c Normal file
View File

@ -0,0 +1,712 @@
/*
* 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
*
*/
#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 <net/9p/9p.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#include <rdma/ib_verbs.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 (4*4096) /* Min SGE is 4, so we can
* safely advertise a maxsize
* of 64k */
#define P9_RDMA_MAX_SGE (P9_RDMA_MAXSIZE >> PAGE_SHIFT)
/**
* 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
* @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.
* @addr: The remote peer's address
* @req_lock: Protects the active request list
* @send_wait: Wait list when the SQ fills up
* @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;
atomic_t rq_count;
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_options - parse mount options into session structure
* @options: options string passed from mount
* @opts: 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;
int ret;
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;
options = kstrdup(params, GFP_KERNEL);
if (!options) {
P9_DPRINTK(P9_DEBUG_ERROR,
"failed to allocate copy of option string\n");
return -ENOMEM;
}
while ((p = strsep(&options, ",")) != NULL) {
int token;
int r;
if (!*p)
continue;
token = match_token(p, tokens, args);
r = match_int(&args[0], &option);
if (r < 0) {
P9_DPRINTK(P9_DEBUG_ERROR,
"integer field, but no integer?\n");
ret = r;
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(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;
req->rc = c->rc;
p9_client_cb(client, req);
return;
err_out:
P9_DPRINTK(P9_DEBUG_ERROR, "req %p err %d status %d\n",
req, err, status);
rdma->state = P9_RDMA_FLUSHING;
client->status = Disconnected;
return;
}
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_DPRINTK(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:
atomic_dec(&rdma->rq_count);
handle_recv(client, rdma, c, wc.status, wc.byte_len);
break;
case IB_WC_SEND:
handle_send(client, rdma, c, wc.status, wc.byte_len);
up(&rdma->sq_sem);
break;
default:
printk(KERN_ERR "9prdma: 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_DPRINTK(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_DPRINTK(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;
/* Allocate an fcall for the reply */
rpl_context = kmalloc(sizeof *rpl_context, GFP_KERNEL);
if (!rpl_context)
goto err_close;
/*
* If the request has a buffer, steal it, otherwise
* allocate a new one. Typically, requests should already
* have receive buffers allocated and just swap them around
*/
if (!req->rc) {
req->rc = kmalloc(sizeof(struct p9_fcall)+client->msize,
GFP_KERNEL);
if (req->rc) {
req->rc->sdata = (char *) req->rc +
sizeof(struct p9_fcall);
req->rc->capacity = client->msize;
}
}
rpl_context->rc = req->rc;
if (!rpl_context->rc) {
kfree(rpl_context);
goto err_close;
}
/*
* 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 (atomic_inc_return(&rdma->rq_count) <= rdma->rq_depth) {
err = post_recv(client, rpl_context);
if (err) {
kfree(rpl_context->rc);
kfree(rpl_context);
goto err_close;
}
} else
atomic_dec(&rdma->rq_count);
/* remove posted receive buffer from request structure */
req->rc = NULL;
/* Post the request */
c = kmalloc(sizeof *c, GFP_KERNEL);
if (!c)
goto err_close;
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))
goto 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))
goto error;
return ib_post_send(rdma->qp, &wr, &bad_wr);
error:
P9_DPRINTK(P9_DEBUG_ERROR, "EIO\n");
return -EIO;
err_close:
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
* @msize: MTU
* @dotu: Extension attribute
* @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);
atomic_set(&rdma->rq_count, 0);
return rdma;
}
/* its not clear to me we can do anything after send has been posted */
static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
{
return 1;
}
/**
* 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);
if (IS_ERR(rdma->cm_id))
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;
/* 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->trans = rdma;
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,
};
/**
* 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");