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linuxdebug/net/sunrpc/xprtrdma/verbs.c

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null pointer error
2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Copyright (c) 2014-2017 Oracle. All rights reserved.
* Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the BSD-type
* license below:
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of the Network Appliance, Inc. nor the names of
* its contributors may be used to endorse or promote products
* derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* verbs.c
*
* Encapsulates the major functions managing:
* o adapters
* o endpoints
* o connections
* o buffer memory
*/
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/svc_rdma.h>
#include <linux/log2.h>
#include <asm-generic/barrier.h>
#include <asm/bitops.h>
#include <rdma/ib_cm.h>
#include "xprt_rdma.h"
#include <trace/events/rpcrdma.h>
static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt);
static void rpcrdma_sendctxs_destroy(struct rpcrdma_xprt *r_xprt);
static void rpcrdma_sendctx_put_locked(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_sendctx *sc);
static int rpcrdma_reqs_setup(struct rpcrdma_xprt *r_xprt);
static void rpcrdma_reqs_reset(struct rpcrdma_xprt *r_xprt);
static void rpcrdma_rep_destroy(struct rpcrdma_rep *rep);
static void rpcrdma_reps_unmap(struct rpcrdma_xprt *r_xprt);
static void rpcrdma_mrs_create(struct rpcrdma_xprt *r_xprt);
static void rpcrdma_mrs_destroy(struct rpcrdma_xprt *r_xprt);
static void rpcrdma_ep_get(struct rpcrdma_ep *ep);
static int rpcrdma_ep_put(struct rpcrdma_ep *ep);
static struct rpcrdma_regbuf *
rpcrdma_regbuf_alloc(size_t size, enum dma_data_direction direction);
static void rpcrdma_regbuf_dma_unmap(struct rpcrdma_regbuf *rb);
static void rpcrdma_regbuf_free(struct rpcrdma_regbuf *rb);
/* Wait for outstanding transport work to finish. ib_drain_qp
* handles the drains in the wrong order for us, so open code
* them here.
*/
static void rpcrdma_xprt_drain(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_ep *ep = r_xprt->rx_ep;
struct rdma_cm_id *id = ep->re_id;
/* Wait for rpcrdma_post_recvs() to leave its critical
* section.
*/
if (atomic_inc_return(&ep->re_receiving) > 1)
wait_for_completion(&ep->re_done);
/* Flush Receives, then wait for deferred Reply work
* to complete.
*/
ib_drain_rq(id->qp);
/* Deferred Reply processing might have scheduled
* local invalidations.
*/
ib_drain_sq(id->qp);
rpcrdma_ep_put(ep);
}
/* Ensure xprt_force_disconnect() is invoked exactly once when a
* connection is closed or lost. (The important thing is it needs
* to be invoked "at least" once).
*/
void rpcrdma_force_disconnect(struct rpcrdma_ep *ep)
{
if (atomic_add_unless(&ep->re_force_disconnect, 1, 1))
xprt_force_disconnect(ep->re_xprt);
}
/**
* rpcrdma_flush_disconnect - Disconnect on flushed completion
* @r_xprt: transport to disconnect
* @wc: work completion entry
*
* Must be called in process context.
*/
void rpcrdma_flush_disconnect(struct rpcrdma_xprt *r_xprt, struct ib_wc *wc)
{
if (wc->status != IB_WC_SUCCESS)
rpcrdma_force_disconnect(r_xprt->rx_ep);
}
/**
* rpcrdma_wc_send - Invoked by RDMA provider for each polled Send WC
* @cq: completion queue
* @wc: WCE for a completed Send WR
*
*/
static void rpcrdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
{
struct ib_cqe *cqe = wc->wr_cqe;
struct rpcrdma_sendctx *sc =
container_of(cqe, struct rpcrdma_sendctx, sc_cqe);
struct rpcrdma_xprt *r_xprt = cq->cq_context;
/* WARNING: Only wr_cqe and status are reliable at this point */
trace_xprtrdma_wc_send(wc, &sc->sc_cid);
rpcrdma_sendctx_put_locked(r_xprt, sc);
rpcrdma_flush_disconnect(r_xprt, wc);
}
/**
* rpcrdma_wc_receive - Invoked by RDMA provider for each polled Receive WC
* @cq: completion queue
* @wc: WCE for a completed Receive WR
*
*/
static void rpcrdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
{
struct ib_cqe *cqe = wc->wr_cqe;
struct rpcrdma_rep *rep = container_of(cqe, struct rpcrdma_rep,
rr_cqe);
struct rpcrdma_xprt *r_xprt = cq->cq_context;
/* WARNING: Only wr_cqe and status are reliable at this point */
trace_xprtrdma_wc_receive(wc, &rep->rr_cid);
--r_xprt->rx_ep->re_receive_count;
if (wc->status != IB_WC_SUCCESS)
goto out_flushed;
/* status == SUCCESS means all fields in wc are trustworthy */
rpcrdma_set_xdrlen(&rep->rr_hdrbuf, wc->byte_len);
rep->rr_wc_flags = wc->wc_flags;
rep->rr_inv_rkey = wc->ex.invalidate_rkey;
ib_dma_sync_single_for_cpu(rdmab_device(rep->rr_rdmabuf),
rdmab_addr(rep->rr_rdmabuf),
wc->byte_len, DMA_FROM_DEVICE);
rpcrdma_reply_handler(rep);
return;
out_flushed:
rpcrdma_flush_disconnect(r_xprt, wc);
rpcrdma_rep_put(&r_xprt->rx_buf, rep);
}
static void rpcrdma_update_cm_private(struct rpcrdma_ep *ep,
struct rdma_conn_param *param)
{
const struct rpcrdma_connect_private *pmsg = param->private_data;
unsigned int rsize, wsize;
/* Default settings for RPC-over-RDMA Version One */
rsize = RPCRDMA_V1_DEF_INLINE_SIZE;
wsize = RPCRDMA_V1_DEF_INLINE_SIZE;
if (pmsg &&
pmsg->cp_magic == rpcrdma_cmp_magic &&
pmsg->cp_version == RPCRDMA_CMP_VERSION) {
rsize = rpcrdma_decode_buffer_size(pmsg->cp_send_size);
wsize = rpcrdma_decode_buffer_size(pmsg->cp_recv_size);
}
if (rsize < ep->re_inline_recv)
ep->re_inline_recv = rsize;
if (wsize < ep->re_inline_send)
ep->re_inline_send = wsize;
rpcrdma_set_max_header_sizes(ep);
}
/**
* rpcrdma_cm_event_handler - Handle RDMA CM events
* @id: rdma_cm_id on which an event has occurred
* @event: details of the event
*
* Called with @id's mutex held. Returns 1 if caller should
* destroy @id, otherwise 0.
*/
static int
rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
{
struct sockaddr *sap = (struct sockaddr *)&id->route.addr.dst_addr;
struct rpcrdma_ep *ep = id->context;
might_sleep();
switch (event->event) {
case RDMA_CM_EVENT_ADDR_RESOLVED:
case RDMA_CM_EVENT_ROUTE_RESOLVED:
ep->re_async_rc = 0;
complete(&ep->re_done);
return 0;
case RDMA_CM_EVENT_ADDR_ERROR:
ep->re_async_rc = -EPROTO;
complete(&ep->re_done);
return 0;
case RDMA_CM_EVENT_ROUTE_ERROR:
ep->re_async_rc = -ENETUNREACH;
complete(&ep->re_done);
return 0;
case RDMA_CM_EVENT_DEVICE_REMOVAL:
pr_info("rpcrdma: removing device %s for %pISpc\n",
ep->re_id->device->name, sap);
fallthrough;
case RDMA_CM_EVENT_ADDR_CHANGE:
ep->re_connect_status = -ENODEV;
goto disconnected;
case RDMA_CM_EVENT_ESTABLISHED:
rpcrdma_ep_get(ep);
ep->re_connect_status = 1;
rpcrdma_update_cm_private(ep, &event->param.conn);
trace_xprtrdma_inline_thresh(ep);
wake_up_all(&ep->re_connect_wait);
break;
case RDMA_CM_EVENT_CONNECT_ERROR:
ep->re_connect_status = -ENOTCONN;
goto wake_connect_worker;
case RDMA_CM_EVENT_UNREACHABLE:
ep->re_connect_status = -ENETUNREACH;
goto wake_connect_worker;
case RDMA_CM_EVENT_REJECTED:
ep->re_connect_status = -ECONNREFUSED;
if (event->status == IB_CM_REJ_STALE_CONN)
ep->re_connect_status = -ENOTCONN;
wake_connect_worker:
wake_up_all(&ep->re_connect_wait);
return 0;
case RDMA_CM_EVENT_DISCONNECTED:
ep->re_connect_status = -ECONNABORTED;
disconnected:
rpcrdma_force_disconnect(ep);
return rpcrdma_ep_put(ep);
default:
break;
}
return 0;
}
static struct rdma_cm_id *rpcrdma_create_id(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_ep *ep)
{
unsigned long wtimeout = msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT) + 1;
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
struct rdma_cm_id *id;
int rc;
init_completion(&ep->re_done);
id = rdma_create_id(xprt->xprt_net, rpcrdma_cm_event_handler, ep,
RDMA_PS_TCP, IB_QPT_RC);
if (IS_ERR(id))
return id;
ep->re_async_rc = -ETIMEDOUT;
rc = rdma_resolve_addr(id, NULL, (struct sockaddr *)&xprt->addr,
RDMA_RESOLVE_TIMEOUT);
if (rc)
goto out;
rc = wait_for_completion_interruptible_timeout(&ep->re_done, wtimeout);
if (rc < 0)
goto out;
rc = ep->re_async_rc;
if (rc)
goto out;
ep->re_async_rc = -ETIMEDOUT;
rc = rdma_resolve_route(id, RDMA_RESOLVE_TIMEOUT);
if (rc)
goto out;
rc = wait_for_completion_interruptible_timeout(&ep->re_done, wtimeout);
if (rc < 0)
goto out;
rc = ep->re_async_rc;
if (rc)
goto out;
return id;
out:
rdma_destroy_id(id);
return ERR_PTR(rc);
}
static void rpcrdma_ep_destroy(struct kref *kref)
{
struct rpcrdma_ep *ep = container_of(kref, struct rpcrdma_ep, re_kref);
if (ep->re_id->qp) {
rdma_destroy_qp(ep->re_id);
ep->re_id->qp = NULL;
}
if (ep->re_attr.recv_cq)
ib_free_cq(ep->re_attr.recv_cq);
ep->re_attr.recv_cq = NULL;
if (ep->re_attr.send_cq)
ib_free_cq(ep->re_attr.send_cq);
ep->re_attr.send_cq = NULL;
if (ep->re_pd)
ib_dealloc_pd(ep->re_pd);
ep->re_pd = NULL;
kfree(ep);
module_put(THIS_MODULE);
}
static noinline void rpcrdma_ep_get(struct rpcrdma_ep *ep)
{
kref_get(&ep->re_kref);
}
/* Returns:
* %0 if @ep still has a positive kref count, or
* %1 if @ep was destroyed successfully.
*/
static noinline int rpcrdma_ep_put(struct rpcrdma_ep *ep)
{
return kref_put(&ep->re_kref, rpcrdma_ep_destroy);
}
static int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_connect_private *pmsg;
struct ib_device *device;
struct rdma_cm_id *id;
struct rpcrdma_ep *ep;
int rc;
ep = kzalloc(sizeof(*ep), XPRTRDMA_GFP_FLAGS);
if (!ep)
return -ENOTCONN;
ep->re_xprt = &r_xprt->rx_xprt;
kref_init(&ep->re_kref);
id = rpcrdma_create_id(r_xprt, ep);
if (IS_ERR(id)) {
kfree(ep);
return PTR_ERR(id);
}
__module_get(THIS_MODULE);
device = id->device;
ep->re_id = id;
reinit_completion(&ep->re_done);
ep->re_max_requests = r_xprt->rx_xprt.max_reqs;
ep->re_inline_send = xprt_rdma_max_inline_write;
ep->re_inline_recv = xprt_rdma_max_inline_read;
rc = frwr_query_device(ep, device);
if (rc)
goto out_destroy;
r_xprt->rx_buf.rb_max_requests = cpu_to_be32(ep->re_max_requests);
ep->re_attr.srq = NULL;
ep->re_attr.cap.max_inline_data = 0;
ep->re_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
ep->re_attr.qp_type = IB_QPT_RC;
ep->re_attr.port_num = ~0;
ep->re_send_batch = ep->re_max_requests >> 3;
ep->re_send_count = ep->re_send_batch;
init_waitqueue_head(&ep->re_connect_wait);
ep->re_attr.send_cq = ib_alloc_cq_any(device, r_xprt,
ep->re_attr.cap.max_send_wr,
IB_POLL_WORKQUEUE);
if (IS_ERR(ep->re_attr.send_cq)) {
rc = PTR_ERR(ep->re_attr.send_cq);
ep->re_attr.send_cq = NULL;
goto out_destroy;
}
ep->re_attr.recv_cq = ib_alloc_cq_any(device, r_xprt,
ep->re_attr.cap.max_recv_wr,
IB_POLL_WORKQUEUE);
if (IS_ERR(ep->re_attr.recv_cq)) {
rc = PTR_ERR(ep->re_attr.recv_cq);
ep->re_attr.recv_cq = NULL;
goto out_destroy;
}
ep->re_receive_count = 0;
/* Initialize cma parameters */
memset(&ep->re_remote_cma, 0, sizeof(ep->re_remote_cma));
/* Prepare RDMA-CM private message */
pmsg = &ep->re_cm_private;
pmsg->cp_magic = rpcrdma_cmp_magic;
pmsg->cp_version = RPCRDMA_CMP_VERSION;
pmsg->cp_flags |= RPCRDMA_CMP_F_SND_W_INV_OK;
pmsg->cp_send_size = rpcrdma_encode_buffer_size(ep->re_inline_send);
pmsg->cp_recv_size = rpcrdma_encode_buffer_size(ep->re_inline_recv);
ep->re_remote_cma.private_data = pmsg;
ep->re_remote_cma.private_data_len = sizeof(*pmsg);
/* Client offers RDMA Read but does not initiate */
ep->re_remote_cma.initiator_depth = 0;
ep->re_remote_cma.responder_resources =
min_t(int, U8_MAX, device->attrs.max_qp_rd_atom);
/* Limit transport retries so client can detect server
* GID changes quickly. RPC layer handles re-establishing
* transport connection and retransmission.
*/
ep->re_remote_cma.retry_count = 6;
/* RPC-over-RDMA handles its own flow control. In addition,
* make all RNR NAKs visible so we know that RPC-over-RDMA
* flow control is working correctly (no NAKs should be seen).
*/
ep->re_remote_cma.flow_control = 0;
ep->re_remote_cma.rnr_retry_count = 0;
ep->re_pd = ib_alloc_pd(device, 0);
if (IS_ERR(ep->re_pd)) {
rc = PTR_ERR(ep->re_pd);
ep->re_pd = NULL;
goto out_destroy;
}
rc = rdma_create_qp(id, ep->re_pd, &ep->re_attr);
if (rc)
goto out_destroy;
r_xprt->rx_ep = ep;
return 0;
out_destroy:
rpcrdma_ep_put(ep);
rdma_destroy_id(id);
return rc;
}
/**
* rpcrdma_xprt_connect - Connect an unconnected transport
* @r_xprt: controlling transport instance
*
* Returns 0 on success or a negative errno.
*/
int rpcrdma_xprt_connect(struct rpcrdma_xprt *r_xprt)
{
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
struct rpcrdma_ep *ep;
int rc;
rc = rpcrdma_ep_create(r_xprt);
if (rc)
return rc;
ep = r_xprt->rx_ep;
xprt_clear_connected(xprt);
rpcrdma_reset_cwnd(r_xprt);
/* Bump the ep's reference count while there are
* outstanding Receives.
*/
rpcrdma_ep_get(ep);
rpcrdma_post_recvs(r_xprt, 1, true);
rc = rdma_connect(ep->re_id, &ep->re_remote_cma);
if (rc)
goto out;
if (xprt->reestablish_timeout < RPCRDMA_INIT_REEST_TO)
xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
wait_event_interruptible(ep->re_connect_wait,
ep->re_connect_status != 0);
if (ep->re_connect_status <= 0) {
rc = ep->re_connect_status;
goto out;
}
rc = rpcrdma_sendctxs_create(r_xprt);
if (rc) {
rc = -ENOTCONN;
goto out;
}
rc = rpcrdma_reqs_setup(r_xprt);
if (rc) {
rc = -ENOTCONN;
goto out;
}
rpcrdma_mrs_create(r_xprt);
frwr_wp_create(r_xprt);
out:
trace_xprtrdma_connect(r_xprt, rc);
return rc;
}
/**
* rpcrdma_xprt_disconnect - Disconnect underlying transport
* @r_xprt: controlling transport instance
*
* Caller serializes. Either the transport send lock is held,
* or we're being called to destroy the transport.
*
* On return, @r_xprt is completely divested of all hardware
* resources and prepared for the next ->connect operation.
*/
void rpcrdma_xprt_disconnect(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_ep *ep = r_xprt->rx_ep;
struct rdma_cm_id *id;
int rc;
if (!ep)
return;
id = ep->re_id;
rc = rdma_disconnect(id);
trace_xprtrdma_disconnect(r_xprt, rc);
rpcrdma_xprt_drain(r_xprt);
rpcrdma_reps_unmap(r_xprt);
rpcrdma_reqs_reset(r_xprt);
rpcrdma_mrs_destroy(r_xprt);
rpcrdma_sendctxs_destroy(r_xprt);
if (rpcrdma_ep_put(ep))
rdma_destroy_id(id);
r_xprt->rx_ep = NULL;
}
/* Fixed-size circular FIFO queue. This implementation is wait-free and
* lock-free.
*
* Consumer is the code path that posts Sends. This path dequeues a
* sendctx for use by a Send operation. Multiple consumer threads
* are serialized by the RPC transport lock, which allows only one
* ->send_request call at a time.
*
* Producer is the code path that handles Send completions. This path
* enqueues a sendctx that has been completed. Multiple producer
* threads are serialized by the ib_poll_cq() function.
*/
/* rpcrdma_sendctxs_destroy() assumes caller has already quiesced
* queue activity, and rpcrdma_xprt_drain has flushed all remaining
* Send requests.
*/
static void rpcrdma_sendctxs_destroy(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
unsigned long i;
if (!buf->rb_sc_ctxs)
return;
for (i = 0; i <= buf->rb_sc_last; i++)
kfree(buf->rb_sc_ctxs[i]);
kfree(buf->rb_sc_ctxs);
buf->rb_sc_ctxs = NULL;
}
static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ep *ep)
{
struct rpcrdma_sendctx *sc;
sc = kzalloc(struct_size(sc, sc_sges, ep->re_attr.cap.max_send_sge),
XPRTRDMA_GFP_FLAGS);
if (!sc)
return NULL;
sc->sc_cqe.done = rpcrdma_wc_send;
sc->sc_cid.ci_queue_id = ep->re_attr.send_cq->res.id;
sc->sc_cid.ci_completion_id =
atomic_inc_return(&ep->re_completion_ids);
return sc;
}
static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_sendctx *sc;
unsigned long i;
/* Maximum number of concurrent outstanding Send WRs. Capping
* the circular queue size stops Send Queue overflow by causing
* the ->send_request call to fail temporarily before too many
* Sends are posted.
*/
i = r_xprt->rx_ep->re_max_requests + RPCRDMA_MAX_BC_REQUESTS;
buf->rb_sc_ctxs = kcalloc(i, sizeof(sc), XPRTRDMA_GFP_FLAGS);
if (!buf->rb_sc_ctxs)
return -ENOMEM;
buf->rb_sc_last = i - 1;
for (i = 0; i <= buf->rb_sc_last; i++) {
sc = rpcrdma_sendctx_create(r_xprt->rx_ep);
if (!sc)
return -ENOMEM;
buf->rb_sc_ctxs[i] = sc;
}
buf->rb_sc_head = 0;
buf->rb_sc_tail = 0;
return 0;
}
/* The sendctx queue is not guaranteed to have a size that is a
* power of two, thus the helpers in circ_buf.h cannot be used.
* The other option is to use modulus (%), which can be expensive.
*/
static unsigned long rpcrdma_sendctx_next(struct rpcrdma_buffer *buf,
unsigned long item)
{
return likely(item < buf->rb_sc_last) ? item + 1 : 0;
}
/**
* rpcrdma_sendctx_get_locked - Acquire a send context
* @r_xprt: controlling transport instance
*
* Returns pointer to a free send completion context; or NULL if
* the queue is empty.
*
* Usage: Called to acquire an SGE array before preparing a Send WR.
*
* The caller serializes calls to this function (per transport), and
* provides an effective memory barrier that flushes the new value
* of rb_sc_head.
*/
struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_sendctx *sc;
unsigned long next_head;
next_head = rpcrdma_sendctx_next(buf, buf->rb_sc_head);
if (next_head == READ_ONCE(buf->rb_sc_tail))
goto out_emptyq;
/* ORDER: item must be accessed _before_ head is updated */
sc = buf->rb_sc_ctxs[next_head];
/* Releasing the lock in the caller acts as a memory
* barrier that flushes rb_sc_head.
*/
buf->rb_sc_head = next_head;
return sc;
out_emptyq:
/* The queue is "empty" if there have not been enough Send
* completions recently. This is a sign the Send Queue is
* backing up. Cause the caller to pause and try again.
*/
xprt_wait_for_buffer_space(&r_xprt->rx_xprt);
r_xprt->rx_stats.empty_sendctx_q++;
return NULL;
}
/**
* rpcrdma_sendctx_put_locked - Release a send context
* @r_xprt: controlling transport instance
* @sc: send context to release
*
* Usage: Called from Send completion to return a sendctxt
* to the queue.
*
* The caller serializes calls to this function (per transport).
*/
static void rpcrdma_sendctx_put_locked(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_sendctx *sc)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
unsigned long next_tail;
/* Unmap SGEs of previously completed but unsignaled
* Sends by walking up the queue until @sc is found.
*/
next_tail = buf->rb_sc_tail;
do {
next_tail = rpcrdma_sendctx_next(buf, next_tail);
/* ORDER: item must be accessed _before_ tail is updated */
rpcrdma_sendctx_unmap(buf->rb_sc_ctxs[next_tail]);
} while (buf->rb_sc_ctxs[next_tail] != sc);
/* Paired with READ_ONCE */
smp_store_release(&buf->rb_sc_tail, next_tail);
xprt_write_space(&r_xprt->rx_xprt);
}
static void
rpcrdma_mrs_create(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_ep *ep = r_xprt->rx_ep;
struct ib_device *device = ep->re_id->device;
unsigned int count;
/* Try to allocate enough to perform one full-sized I/O */
for (count = 0; count < ep->re_max_rdma_segs; count++) {
struct rpcrdma_mr *mr;
int rc;
mr = kzalloc_node(sizeof(*mr), XPRTRDMA_GFP_FLAGS,
ibdev_to_node(device));
if (!mr)
break;
rc = frwr_mr_init(r_xprt, mr);
if (rc) {
kfree(mr);
break;
}
spin_lock(&buf->rb_lock);
rpcrdma_mr_push(mr, &buf->rb_mrs);
list_add(&mr->mr_all, &buf->rb_all_mrs);
spin_unlock(&buf->rb_lock);
}
r_xprt->rx_stats.mrs_allocated += count;
trace_xprtrdma_createmrs(r_xprt, count);
}
static void
rpcrdma_mr_refresh_worker(struct work_struct *work)
{
struct rpcrdma_buffer *buf = container_of(work, struct rpcrdma_buffer,
rb_refresh_worker);
struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt,
rx_buf);
rpcrdma_mrs_create(r_xprt);
xprt_write_space(&r_xprt->rx_xprt);
}
/**
* rpcrdma_mrs_refresh - Wake the MR refresh worker
* @r_xprt: controlling transport instance
*
*/
void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_ep *ep = r_xprt->rx_ep;
/* If there is no underlying connection, it's no use
* to wake the refresh worker.
*/
if (ep->re_connect_status != 1)
return;
queue_work(system_highpri_wq, &buf->rb_refresh_worker);
}
/**
* rpcrdma_req_create - Allocate an rpcrdma_req object
* @r_xprt: controlling r_xprt
* @size: initial size, in bytes, of send and receive buffers
*
* Returns an allocated and fully initialized rpcrdma_req or NULL.
*/
struct rpcrdma_req *rpcrdma_req_create(struct rpcrdma_xprt *r_xprt,
size_t size)
{
struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
struct rpcrdma_req *req;
req = kzalloc(sizeof(*req), XPRTRDMA_GFP_FLAGS);
if (req == NULL)
goto out1;
req->rl_sendbuf = rpcrdma_regbuf_alloc(size, DMA_TO_DEVICE);
if (!req->rl_sendbuf)
goto out2;
req->rl_recvbuf = rpcrdma_regbuf_alloc(size, DMA_NONE);
if (!req->rl_recvbuf)
goto out3;
INIT_LIST_HEAD(&req->rl_free_mrs);
INIT_LIST_HEAD(&req->rl_registered);
spin_lock(&buffer->rb_lock);
list_add(&req->rl_all, &buffer->rb_allreqs);
spin_unlock(&buffer->rb_lock);
return req;
out3:
rpcrdma_regbuf_free(req->rl_sendbuf);
out2:
kfree(req);
out1:
return NULL;
}
/**
* rpcrdma_req_setup - Per-connection instance setup of an rpcrdma_req object
* @r_xprt: controlling transport instance
* @req: rpcrdma_req object to set up
*
* Returns zero on success, and a negative errno on failure.
*/
int rpcrdma_req_setup(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
{
struct rpcrdma_regbuf *rb;
size_t maxhdrsize;
/* Compute maximum header buffer size in bytes */
maxhdrsize = rpcrdma_fixed_maxsz + 3 +
r_xprt->rx_ep->re_max_rdma_segs * rpcrdma_readchunk_maxsz;
maxhdrsize *= sizeof(__be32);
rb = rpcrdma_regbuf_alloc(__roundup_pow_of_two(maxhdrsize),
DMA_TO_DEVICE);
if (!rb)
goto out;
if (!__rpcrdma_regbuf_dma_map(r_xprt, rb))
goto out_free;
req->rl_rdmabuf = rb;
xdr_buf_init(&req->rl_hdrbuf, rdmab_data(rb), rdmab_length(rb));
return 0;
out_free:
rpcrdma_regbuf_free(rb);
out:
return -ENOMEM;
}
/* ASSUMPTION: the rb_allreqs list is stable for the duration,
* and thus can be walked without holding rb_lock. Eg. the
* caller is holding the transport send lock to exclude
* device removal or disconnection.
*/
static int rpcrdma_reqs_setup(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_req *req;
int rc;
list_for_each_entry(req, &buf->rb_allreqs, rl_all) {
rc = rpcrdma_req_setup(r_xprt, req);
if (rc)
return rc;
}
return 0;
}
static void rpcrdma_req_reset(struct rpcrdma_req *req)
{
/* Credits are valid for only one connection */
req->rl_slot.rq_cong = 0;
rpcrdma_regbuf_free(req->rl_rdmabuf);
req->rl_rdmabuf = NULL;
rpcrdma_regbuf_dma_unmap(req->rl_sendbuf);
rpcrdma_regbuf_dma_unmap(req->rl_recvbuf);
frwr_reset(req);
}
/* ASSUMPTION: the rb_allreqs list is stable for the duration,
* and thus can be walked without holding rb_lock. Eg. the
* caller is holding the transport send lock to exclude
* device removal or disconnection.
*/
static void rpcrdma_reqs_reset(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_req *req;
list_for_each_entry(req, &buf->rb_allreqs, rl_all)
rpcrdma_req_reset(req);
}
static noinline
struct rpcrdma_rep *rpcrdma_rep_create(struct rpcrdma_xprt *r_xprt,
bool temp)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_rep *rep;
rep = kzalloc(sizeof(*rep), XPRTRDMA_GFP_FLAGS);
if (rep == NULL)
goto out;
rep->rr_rdmabuf = rpcrdma_regbuf_alloc(r_xprt->rx_ep->re_inline_recv,
DMA_FROM_DEVICE);
if (!rep->rr_rdmabuf)
goto out_free;
rep->rr_cid.ci_completion_id =
atomic_inc_return(&r_xprt->rx_ep->re_completion_ids);
xdr_buf_init(&rep->rr_hdrbuf, rdmab_data(rep->rr_rdmabuf),
rdmab_length(rep->rr_rdmabuf));
rep->rr_cqe.done = rpcrdma_wc_receive;
rep->rr_rxprt = r_xprt;
rep->rr_recv_wr.next = NULL;
rep->rr_recv_wr.wr_cqe = &rep->rr_cqe;
rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
rep->rr_recv_wr.num_sge = 1;
rep->rr_temp = temp;
spin_lock(&buf->rb_lock);
list_add(&rep->rr_all, &buf->rb_all_reps);
spin_unlock(&buf->rb_lock);
return rep;
out_free:
kfree(rep);
out:
return NULL;
}
static void rpcrdma_rep_free(struct rpcrdma_rep *rep)
{
rpcrdma_regbuf_free(rep->rr_rdmabuf);
kfree(rep);
}
static void rpcrdma_rep_destroy(struct rpcrdma_rep *rep)
{
struct rpcrdma_buffer *buf = &rep->rr_rxprt->rx_buf;
spin_lock(&buf->rb_lock);
list_del(&rep->rr_all);
spin_unlock(&buf->rb_lock);
rpcrdma_rep_free(rep);
}
static struct rpcrdma_rep *rpcrdma_rep_get_locked(struct rpcrdma_buffer *buf)
{
struct llist_node *node;
/* Calls to llist_del_first are required to be serialized */
node = llist_del_first(&buf->rb_free_reps);
if (!node)
return NULL;
return llist_entry(node, struct rpcrdma_rep, rr_node);
}
/**
* rpcrdma_rep_put - Release rpcrdma_rep back to free list
* @buf: buffer pool
* @rep: rep to release
*
*/
void rpcrdma_rep_put(struct rpcrdma_buffer *buf, struct rpcrdma_rep *rep)
{
llist_add(&rep->rr_node, &buf->rb_free_reps);
}
/* Caller must ensure the QP is quiescent (RQ is drained) before
* invoking this function, to guarantee rb_all_reps is not
* changing.
*/
static void rpcrdma_reps_unmap(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_rep *rep;
list_for_each_entry(rep, &buf->rb_all_reps, rr_all) {
rpcrdma_regbuf_dma_unmap(rep->rr_rdmabuf);
rep->rr_temp = true; /* Mark this rep for destruction */
}
}
static void rpcrdma_reps_destroy(struct rpcrdma_buffer *buf)
{
struct rpcrdma_rep *rep;
spin_lock(&buf->rb_lock);
while ((rep = list_first_entry_or_null(&buf->rb_all_reps,
struct rpcrdma_rep,
rr_all)) != NULL) {
list_del(&rep->rr_all);
spin_unlock(&buf->rb_lock);
rpcrdma_rep_free(rep);
spin_lock(&buf->rb_lock);
}
spin_unlock(&buf->rb_lock);
}
/**
* rpcrdma_buffer_create - Create initial set of req/rep objects
* @r_xprt: transport instance to (re)initialize
*
* Returns zero on success, otherwise a negative errno.
*/
int rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
int i, rc;
buf->rb_bc_srv_max_requests = 0;
spin_lock_init(&buf->rb_lock);
INIT_LIST_HEAD(&buf->rb_mrs);
INIT_LIST_HEAD(&buf->rb_all_mrs);
INIT_WORK(&buf->rb_refresh_worker, rpcrdma_mr_refresh_worker);
INIT_LIST_HEAD(&buf->rb_send_bufs);
INIT_LIST_HEAD(&buf->rb_allreqs);
INIT_LIST_HEAD(&buf->rb_all_reps);
rc = -ENOMEM;
for (i = 0; i < r_xprt->rx_xprt.max_reqs; i++) {
struct rpcrdma_req *req;
req = rpcrdma_req_create(r_xprt,
RPCRDMA_V1_DEF_INLINE_SIZE * 2);
if (!req)
goto out;
list_add(&req->rl_list, &buf->rb_send_bufs);
}
init_llist_head(&buf->rb_free_reps);
return 0;
out:
rpcrdma_buffer_destroy(buf);
return rc;
}
/**
* rpcrdma_req_destroy - Destroy an rpcrdma_req object
* @req: unused object to be destroyed
*
* Relies on caller holding the transport send lock to protect
* removing req->rl_all from buf->rb_all_reqs safely.
*/
void rpcrdma_req_destroy(struct rpcrdma_req *req)
{
struct rpcrdma_mr *mr;
list_del(&req->rl_all);
while ((mr = rpcrdma_mr_pop(&req->rl_free_mrs))) {
struct rpcrdma_buffer *buf = &mr->mr_xprt->rx_buf;
spin_lock(&buf->rb_lock);
list_del(&mr->mr_all);
spin_unlock(&buf->rb_lock);
frwr_mr_release(mr);
}
rpcrdma_regbuf_free(req->rl_recvbuf);
rpcrdma_regbuf_free(req->rl_sendbuf);
rpcrdma_regbuf_free(req->rl_rdmabuf);
kfree(req);
}
/**
* rpcrdma_mrs_destroy - Release all of a transport's MRs
* @r_xprt: controlling transport instance
*
* Relies on caller holding the transport send lock to protect
* removing mr->mr_list from req->rl_free_mrs safely.
*/
static void rpcrdma_mrs_destroy(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_mr *mr;
cancel_work_sync(&buf->rb_refresh_worker);
spin_lock(&buf->rb_lock);
while ((mr = list_first_entry_or_null(&buf->rb_all_mrs,
struct rpcrdma_mr,
mr_all)) != NULL) {
list_del(&mr->mr_list);
list_del(&mr->mr_all);
spin_unlock(&buf->rb_lock);
frwr_mr_release(mr);
spin_lock(&buf->rb_lock);
}
spin_unlock(&buf->rb_lock);
}
/**
* rpcrdma_buffer_destroy - Release all hw resources
* @buf: root control block for resources
*
* ORDERING: relies on a prior rpcrdma_xprt_drain :
* - No more Send or Receive completions can occur
* - All MRs, reps, and reqs are returned to their free lists
*/
void
rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
{
rpcrdma_reps_destroy(buf);
while (!list_empty(&buf->rb_send_bufs)) {
struct rpcrdma_req *req;
req = list_first_entry(&buf->rb_send_bufs,
struct rpcrdma_req, rl_list);
list_del(&req->rl_list);
rpcrdma_req_destroy(req);
}
}
/**
* rpcrdma_mr_get - Allocate an rpcrdma_mr object
* @r_xprt: controlling transport
*
* Returns an initialized rpcrdma_mr or NULL if no free
* rpcrdma_mr objects are available.
*/
struct rpcrdma_mr *
rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_mr *mr;
spin_lock(&buf->rb_lock);
mr = rpcrdma_mr_pop(&buf->rb_mrs);
spin_unlock(&buf->rb_lock);
return mr;
}
/**
* rpcrdma_reply_put - Put reply buffers back into pool
* @buffers: buffer pool
* @req: object to return
*
*/
void rpcrdma_reply_put(struct rpcrdma_buffer *buffers, struct rpcrdma_req *req)
{
if (req->rl_reply) {
rpcrdma_rep_put(buffers, req->rl_reply);
req->rl_reply = NULL;
}
}
/**
* rpcrdma_buffer_get - Get a request buffer
* @buffers: Buffer pool from which to obtain a buffer
*
* Returns a fresh rpcrdma_req, or NULL if none are available.
*/
struct rpcrdma_req *
rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)
{
struct rpcrdma_req *req;
spin_lock(&buffers->rb_lock);
req = list_first_entry_or_null(&buffers->rb_send_bufs,
struct rpcrdma_req, rl_list);
if (req)
list_del_init(&req->rl_list);
spin_unlock(&buffers->rb_lock);
return req;
}
/**
* rpcrdma_buffer_put - Put request/reply buffers back into pool
* @buffers: buffer pool
* @req: object to return
*
*/
void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers, struct rpcrdma_req *req)
{
rpcrdma_reply_put(buffers, req);
spin_lock(&buffers->rb_lock);
list_add(&req->rl_list, &buffers->rb_send_bufs);
spin_unlock(&buffers->rb_lock);
}
/* Returns a pointer to a rpcrdma_regbuf object, or NULL.
*
* xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for
* receiving the payload of RDMA RECV operations. During Long Calls
* or Replies they may be registered externally via frwr_map.
*/
static struct rpcrdma_regbuf *
rpcrdma_regbuf_alloc(size_t size, enum dma_data_direction direction)
{
struct rpcrdma_regbuf *rb;
rb = kmalloc(sizeof(*rb), XPRTRDMA_GFP_FLAGS);
if (!rb)
return NULL;
rb->rg_data = kmalloc(size, XPRTRDMA_GFP_FLAGS);
if (!rb->rg_data) {
kfree(rb);
return NULL;
}
rb->rg_device = NULL;
rb->rg_direction = direction;
rb->rg_iov.length = size;
return rb;
}
/**
* rpcrdma_regbuf_realloc - re-allocate a SEND/RECV buffer
* @rb: regbuf to reallocate
* @size: size of buffer to be allocated, in bytes
* @flags: GFP flags
*
* Returns true if reallocation was successful. If false is
* returned, @rb is left untouched.
*/
bool rpcrdma_regbuf_realloc(struct rpcrdma_regbuf *rb, size_t size, gfp_t flags)
{
void *buf;
buf = kmalloc(size, flags);
if (!buf)
return false;
rpcrdma_regbuf_dma_unmap(rb);
kfree(rb->rg_data);
rb->rg_data = buf;
rb->rg_iov.length = size;
return true;
}
/**
* __rpcrdma_regbuf_dma_map - DMA-map a regbuf
* @r_xprt: controlling transport instance
* @rb: regbuf to be mapped
*
* Returns true if the buffer is now DMA mapped to @r_xprt's device
*/
bool __rpcrdma_regbuf_dma_map(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_regbuf *rb)
{
struct ib_device *device = r_xprt->rx_ep->re_id->device;
if (rb->rg_direction == DMA_NONE)
return false;
rb->rg_iov.addr = ib_dma_map_single(device, rdmab_data(rb),
rdmab_length(rb), rb->rg_direction);
if (ib_dma_mapping_error(device, rdmab_addr(rb))) {
trace_xprtrdma_dma_maperr(rdmab_addr(rb));
return false;
}
rb->rg_device = device;
rb->rg_iov.lkey = r_xprt->rx_ep->re_pd->local_dma_lkey;
return true;
}
static void rpcrdma_regbuf_dma_unmap(struct rpcrdma_regbuf *rb)
{
if (!rb)
return;
if (!rpcrdma_regbuf_is_mapped(rb))
return;
ib_dma_unmap_single(rb->rg_device, rdmab_addr(rb), rdmab_length(rb),
rb->rg_direction);
rb->rg_device = NULL;
}
static void rpcrdma_regbuf_free(struct rpcrdma_regbuf *rb)
{
rpcrdma_regbuf_dma_unmap(rb);
if (rb)
kfree(rb->rg_data);
kfree(rb);
}
/**
* rpcrdma_post_recvs - Refill the Receive Queue
* @r_xprt: controlling transport instance
* @needed: current credit grant
* @temp: mark Receive buffers to be deleted after one use
*
*/
void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, int needed, bool temp)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_ep *ep = r_xprt->rx_ep;
struct ib_recv_wr *wr, *bad_wr;
struct rpcrdma_rep *rep;
int count, rc;
rc = 0;
count = 0;
if (likely(ep->re_receive_count > needed))
goto out;
needed -= ep->re_receive_count;
if (!temp)
needed += RPCRDMA_MAX_RECV_BATCH;
if (atomic_inc_return(&ep->re_receiving) > 1)
goto out;
/* fast path: all needed reps can be found on the free list */
wr = NULL;
while (needed) {
rep = rpcrdma_rep_get_locked(buf);
if (rep && rep->rr_temp) {
rpcrdma_rep_destroy(rep);
continue;
}
if (!rep)
rep = rpcrdma_rep_create(r_xprt, temp);
if (!rep)
break;
if (!rpcrdma_regbuf_dma_map(r_xprt, rep->rr_rdmabuf)) {
rpcrdma_rep_put(buf, rep);
break;
}
rep->rr_cid.ci_queue_id = ep->re_attr.recv_cq->res.id;
trace_xprtrdma_post_recv(rep);
rep->rr_recv_wr.next = wr;
wr = &rep->rr_recv_wr;
--needed;
++count;
}
if (!wr)
goto out;
rc = ib_post_recv(ep->re_id->qp, wr,
(const struct ib_recv_wr **)&bad_wr);
if (rc) {
trace_xprtrdma_post_recvs_err(r_xprt, rc);
for (wr = bad_wr; wr;) {
struct rpcrdma_rep *rep;
rep = container_of(wr, struct rpcrdma_rep, rr_recv_wr);
wr = wr->next;
rpcrdma_rep_put(buf, rep);
--count;
}
}
if (atomic_dec_return(&ep->re_receiving) > 0)
complete(&ep->re_done);
out:
trace_xprtrdma_post_recvs(r_xprt, count);
ep->re_receive_count += count;
return;
}