// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Copyright (c) 2016-2018 Oracle. All rights reserved.
* Copyright (c) 2014 Open Grid Computing, Inc. All rights reserved.
* Copyright (c) 2005-2006 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.
*
* Author: Tom Tucker <[email protected]>
*/
/* Operation
*
* The main entry point is svc_rdma_recvfrom. This is called from
* svc_recv when the transport indicates there is incoming data to
* be read. "Data Ready" is signaled when an RDMA Receive completes,
* or when a set of RDMA Reads complete.
*
* An svc_rqst is passed in. This structure contains an array of
* free pages (rq_pages) that will contain the incoming RPC message.
*
* Short messages are moved directly into svc_rqst::rq_arg, and
* the RPC Call is ready to be processed by the Upper Layer.
* svc_rdma_recvfrom returns the length of the RPC Call message,
* completing the reception of the RPC Call.
*
* However, when an incoming message has Read chunks,
* svc_rdma_recvfrom must post RDMA Reads to pull the RPC Call's
* data payload from the client. svc_rdma_recvfrom sets up the
* RDMA Reads using pages in svc_rqst::rq_pages, which are
* transferred to an svc_rdma_recv_ctxt for the duration of the
* I/O. svc_rdma_recvfrom then returns zero, since the RPC message
* is still not yet ready.
*
* When the Read chunk payloads have become available on the
* server, "Data Ready" is raised again, and svc_recv calls
* svc_rdma_recvfrom again. This second call may use a different
* svc_rqst than the first one, thus any information that needs
* to be preserved across these two calls is kept in an
* svc_rdma_recv_ctxt.
*
* The second call to svc_rdma_recvfrom performs final assembly
* of the RPC Call message, using the RDMA Read sink pages kept in
* the svc_rdma_recv_ctxt. The xdr_buf is copied from the
* svc_rdma_recv_ctxt to the second svc_rqst. The second call returns
* the length of the completed RPC Call message.
*
* Page Management
*
* Pages under I/O must be transferred from the first svc_rqst to an
* svc_rdma_recv_ctxt before the first svc_rdma_recvfrom call returns.
*
* The first svc_rqst supplies pages for RDMA Reads. These are moved
* from rqstp::rq_pages into ctxt::pages. The consumed elements of
* the rq_pages array are set to NULL and refilled with the first
* svc_rdma_recvfrom call returns.
*
* During the second svc_rdma_recvfrom call, RDMA Read sink pages
* are transferred from the svc_rdma_recv_ctxt to the second svc_rqst.
*/
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/unaligned.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/sunrpc/svc_rdma.h>
#include "xprt_rdma.h"
#include <trace/events/rpcrdma.h>
static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc);
static inline struct svc_rdma_recv_ctxt *
svc_rdma_next_recv_ctxt(struct list_head *list)
{
return list_first_entry_or_null(list, struct svc_rdma_recv_ctxt,
rc_list);
}
static struct svc_rdma_recv_ctxt *
svc_rdma_recv_ctxt_alloc(struct svcxprt_rdma *rdma)
{
int node = ibdev_to_node(rdma->sc_cm_id->device);
struct svc_rdma_recv_ctxt *ctxt;
dma_addr_t addr;
void *buffer;
ctxt = kzalloc_node(sizeof(*ctxt), GFP_KERNEL, node);
if (!ctxt)
goto fail0;
buffer = kmalloc_node(rdma->sc_max_req_size, GFP_KERNEL, node);
if (!buffer)
goto fail1;
addr = ib_dma_map_single(rdma->sc_pd->device, buffer,
rdma->sc_max_req_size, DMA_FROM_DEVICE);
if (ib_dma_mapping_error(rdma->sc_pd->device, addr))
goto fail2;
svc_rdma_recv_cid_init(rdma, &ctxt->rc_cid);
pcl_init(&ctxt->rc_call_pcl);
pcl_init(&ctxt->rc_read_pcl);
pcl_init(&ctxt->rc_write_pcl);
pcl_init(&ctxt->rc_reply_pcl);
ctxt->rc_recv_wr.next = NULL;
ctxt->rc_recv_wr.wr_cqe = &ctxt->rc_cqe;
ctxt->rc_recv_wr.sg_list = &ctxt->rc_recv_sge;
ctxt->rc_recv_wr.num_sge = 1;
ctxt->rc_cqe.done = svc_rdma_wc_receive;
ctxt->rc_recv_sge.addr = addr;
ctxt->rc_recv_sge.length = rdma->sc_max_req_size;
ctxt->rc_recv_sge.lkey = rdma->sc_pd->local_dma_lkey;
ctxt->rc_recv_buf = buffer;
svc_rdma_cc_init(rdma, &ctxt->rc_cc);
return ctxt;
fail2:
kfree(buffer);
fail1:
kfree(ctxt);
fail0:
return NULL;
}
static void svc_rdma_recv_ctxt_destroy(struct svcxprt_rdma *rdma,
struct svc_rdma_recv_ctxt *ctxt)
{
ib_dma_unmap_single(rdma->sc_pd->device, ctxt->rc_recv_sge.addr,
ctxt->rc_recv_sge.length, DMA_FROM_DEVICE);
kfree(ctxt->rc_recv_buf);
kfree(ctxt);
}
/**
* svc_rdma_recv_ctxts_destroy - Release all recv_ctxt's for an xprt
* @rdma: svcxprt_rdma being torn down
*
*/
void svc_rdma_recv_ctxts_destroy(struct svcxprt_rdma *rdma)
{
struct svc_rdma_recv_ctxt *ctxt;
struct llist_node *node;
while ((node = llist_del_first(&rdma->sc_recv_ctxts))) {
ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node);
svc_rdma_recv_ctxt_destroy(rdma, ctxt);
}
}
/**
* svc_rdma_recv_ctxt_get - Allocate a recv_ctxt
* @rdma: controlling svcxprt_rdma
*
* Returns a recv_ctxt or (rarely) NULL if none are available.
*/
struct svc_rdma_recv_ctxt *svc_rdma_recv_ctxt_get(struct svcxprt_rdma *rdma)
{
struct svc_rdma_recv_ctxt *ctxt;
struct llist_node *node;
node = llist_del_first(&rdma->sc_recv_ctxts);
if (!node)
return NULL;
ctxt = llist_entry(node, struct svc_rdma_recv_ctxt, rc_node);
ctxt->rc_page_count = 0;
return ctxt;
}
/**
* svc_rdma_recv_ctxt_put - Return recv_ctxt to free list
* @rdma: controlling svcxprt_rdma
* @ctxt: object to return to the free list
*
*/
void svc_rdma_recv_ctxt_put(struct svcxprt_rdma *rdma,
struct svc_rdma_recv_ctxt *ctxt)
{
svc_rdma_cc_release(rdma, &ctxt->rc_cc, DMA_FROM_DEVICE);
/* @rc_page_count is normally zero here, but error flows
* can leave pages in @rc_pages.
*/
release_pages(ctxt->rc_pages, ctxt->rc_page_count);
pcl_free(&ctxt->rc_call_pcl);
pcl_free(&ctxt->rc_read_pcl);
pcl_free(&ctxt->rc_write_pcl);
pcl_free(&ctxt->rc_reply_pcl);
llist_add(&ctxt->rc_node, &rdma->sc_recv_ctxts);
}
/**
* svc_rdma_release_ctxt - Release transport-specific per-rqst resources
* @xprt: the transport which owned the context
* @vctxt: the context from rqstp->rq_xprt_ctxt or dr->xprt_ctxt
*
* Ensure that the recv_ctxt is released whether or not a Reply
* was sent. For example, the client could close the connection,
* or svc_process could drop an RPC, before the Reply is sent.
*/
void svc_rdma_release_ctxt(struct svc_xprt *xprt, void *vctxt)
{
struct svc_rdma_recv_ctxt *ctxt = vctxt;
struct svcxprt_rdma *rdma =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
if (ctxt)
svc_rdma_recv_ctxt_put(rdma, ctxt);
}
static bool svc_rdma_refresh_recvs(struct svcxprt_rdma *rdma,
unsigned int wanted)
{
const struct ib_recv_wr *bad_wr = NULL;
struct svc_rdma_recv_ctxt *ctxt;
struct ib_recv_wr *recv_chain;
int ret;
if (test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags))
return false;
recv_chain = NULL;
while (wanted--) {
ctxt = svc_rdma_recv_ctxt_get(rdma);
if (!ctxt)
break;
trace_svcrdma_post_recv(&ctxt->rc_cid);
ctxt->rc_recv_wr.next = recv_chain;
recv_chain = &ctxt->rc_recv_wr;
rdma->sc_pending_recvs++;
}
if (!recv_chain)
return true;
ret = ib_post_recv(rdma->sc_qp, recv_chain, &bad_wr);
if (ret)
goto err_free;
return true;
err_free:
trace_svcrdma_rq_post_err(rdma, ret);
while (bad_wr) {
ctxt = container_of(bad_wr, struct svc_rdma_recv_ctxt,
rc_recv_wr);
bad_wr = bad_wr->next;
svc_rdma_recv_ctxt_put(rdma, ctxt);
}
/* Since we're destroying the xprt, no need to reset
* sc_pending_recvs. */
return false;
}
/**
* svc_rdma_post_recvs - Post initial set of Recv WRs
* @rdma: fresh svcxprt_rdma
*
* Return values:
* %true: Receive Queue initialization successful
* %false: memory allocation or DMA error
*/
bool svc_rdma_post_recvs(struct svcxprt_rdma *rdma)
{
unsigned int total;
/* For each credit, allocate enough recv_ctxts for one
* posted Receive and one RPC in process.
*/
total = (rdma->sc_max_requests * 2) + rdma->sc_recv_batch;
while (total--) {
struct svc_rdma_recv_ctxt *ctxt;
ctxt = svc_rdma_recv_ctxt_alloc(rdma);
if (!ctxt)
return false;
llist_add(&ctxt->rc_node, &rdma->sc_recv_ctxts);
}
return svc_rdma_refresh_recvs(rdma, rdma->sc_max_requests);
}
/**
* svc_rdma_wc_receive - Invoked by RDMA provider for each polled Receive WC
* @cq: Completion Queue context
* @wc: Work Completion object
*
*/
static void svc_rdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
{
struct svcxprt_rdma *rdma = cq->cq_context;
struct ib_cqe *cqe = wc->wr_cqe;
struct svc_rdma_recv_ctxt *ctxt;
rdma->sc_pending_recvs--;
/* WARNING: Only wc->wr_cqe and wc->status are reliable */
ctxt = container_of(cqe, struct svc_rdma_recv_ctxt, rc_cqe);
if (wc->status != IB_WC_SUCCESS)
goto flushed;
trace_svcrdma_wc_recv(wc, &ctxt->rc_cid);
/* If receive posting fails, the connection is about to be
* lost anyway. The server will not be able to send a reply
* for this RPC, and the client will retransmit this RPC
* anyway when it reconnects.
*
* Therefore we drop the Receive, even if status was SUCCESS
* to reduce the likelihood of replayed requests once the
* client reconnects.
*/
if (rdma->sc_pending_recvs < rdma->sc_max_requests)
if (!svc_rdma_refresh_recvs(rdma, rdma->sc_recv_batch))
goto dropped;
/* All wc fields are now known to be valid */
ctxt->rc_byte_len = wc->byte_len;
spin_lock(&rdma->sc_rq_dto_lock);
list_add_tail(&ctxt->rc_list, &rdma->sc_rq_dto_q);
/* Note the unlock pairs with the smp_rmb in svc_xprt_ready: */
set_bit(XPT_DATA, &rdma->sc_xprt.xpt_flags);
spin_unlock(&rdma->sc_rq_dto_lock);
if (!test_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags))
svc_xprt_enqueue(&rdma->sc_xprt);
return;
flushed:
if (wc->status == IB_WC_WR_FLUSH_ERR)
trace_svcrdma_wc_recv_flush(wc, &ctxt->rc_cid);
else
trace_svcrdma_wc_recv_err(wc, &ctxt->rc_cid);
dropped:
svc_rdma_recv_ctxt_put(rdma, ctxt);
svc_xprt_deferred_close(&rdma->sc_xprt);
}
/**
* svc_rdma_flush_recv_queues - Drain pending Receive work
* @rdma: svcxprt_rdma being shut down
*
*/
void svc_rdma_flush_recv_queues(struct svcxprt_rdma *rdma)
{
struct svc_rdma_recv_ctxt *ctxt;
while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_read_complete_q))) {
list_del(&ctxt->rc_list);
svc_rdma_recv_ctxt_put(rdma, ctxt);
}
while ((ctxt = svc_rdma_next_recv_ctxt(&rdma->sc_rq_dto_q))) {
list_del(&ctxt->rc_list);
svc_rdma_recv_ctxt_put(rdma, ctxt);
}
}
static void svc_rdma_build_arg_xdr(struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *ctxt)
{
struct xdr_buf *arg = &rqstp->rq_arg;
arg->head[0].iov_base = ctxt->rc_recv_buf;
arg->head[0].iov_len = ctxt->rc_byte_len;
arg->tail[0].iov_base = NULL;
arg->tail[0].iov_len = 0;
arg->page_len = 0;
arg->page_base = 0;
arg->buflen = ctxt->rc_byte_len;
arg->len = ctxt->rc_byte_len;
}
/**
* xdr_count_read_segments - Count number of Read segments in Read list
* @rctxt: Ingress receive context
* @p: Start of an un-decoded Read list
*
* Before allocating anything, ensure the ingress Read list is safe
* to use.
*
* The segment count is limited to how many segments can fit in the
* transport header without overflowing the buffer. That's about 40
* Read segments for a 1KB inline threshold.
*
* Return values:
* %true: Read list is valid. @rctxt's xdr_stream is updated to point
* to the first byte past the Read list. rc_read_pcl and
* rc_call_pcl cl_count fields are set to the number of
* Read segments in the list.
* %false: Read list is corrupt. @rctxt's xdr_stream is left in an
* unknown state.
*/
static bool xdr_count_read_segments(struct svc_rdma_recv_ctxt *rctxt, __be32 *p)
{
rctxt->rc_call_pcl.cl_count = 0;
rctxt->rc_read_pcl.cl_count = 0;
while (xdr_item_is_present(p)) {
u32 position, handle, length;
u64 offset;
p = xdr_inline_decode(&rctxt->rc_stream,
rpcrdma_readseg_maxsz * sizeof(*p));
if (!p)
return false;
xdr_decode_read_segment(p, &position, &handle,
&length, &offset);
if (position) {
if (position & 3)
return false;
++rctxt->rc_read_pcl.cl_count;
} else {
++rctxt->rc_call_pcl.cl_count;
}
p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
if (!p)
return false;
}
return true;
}
/* Sanity check the Read list.
*
* Sanity checks:
* - Read list does not overflow Receive buffer.
* - Chunk size limited by largest NFS data payload.
*
* Return values:
* %true: Read list is valid. @rctxt's xdr_stream is updated
* to point to the first byte past the Read list.
* %false: Read list is corrupt. @rctxt's xdr_stream is left
* in an unknown state.
*/
static bool xdr_check_read_list(struct svc_rdma_recv_ctxt *rctxt)
{
__be32 *p;
p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
if (!p)
return false;
if (!xdr_count_read_segments(rctxt, p))
return false;
if (!pcl_alloc_call(rctxt, p))
return false;
return pcl_alloc_read(rctxt, p);
}
static bool xdr_check_write_chunk(struct svc_rdma_recv_ctxt *rctxt)
{
u32 segcount;
__be32 *p;
if (xdr_stream_decode_u32(&rctxt->rc_stream, &segcount))
return false;
/* A bogus segcount causes this buffer overflow check to fail. */
p = xdr_inline_decode(&rctxt->rc_stream,
segcount * rpcrdma_segment_maxsz * sizeof(*p));
return p != NULL;
}
/**
* xdr_count_write_chunks - Count number of Write chunks in Write list
* @rctxt: Received header and decoding state
* @p: start of an un-decoded Write list
*
* Before allocating anything, ensure the ingress Write list is
* safe to use.
*
* Return values:
* %true: Write list is valid. @rctxt's xdr_stream is updated
* to point to the first byte past the Write list, and
* the number of Write chunks is in rc_write_pcl.cl_count.
* %false: Write list is corrupt. @rctxt's xdr_stream is left
* in an indeterminate state.
*/
static bool xdr_count_write_chunks(struct svc_rdma_recv_ctxt *rctxt, __be32 *p)
{
rctxt->rc_write_pcl.cl_count = 0;
while (xdr_item_is_present(p)) {
if (!xdr_check_write_chunk(rctxt))
return false;
++rctxt->rc_write_pcl.cl_count;
p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
if (!p)
return false;
}
return true;
}
/* Sanity check the Write list.
*
* Implementation limits:
* - This implementation currently supports only one Write chunk.
*
* Sanity checks:
* - Write list does not overflow Receive buffer.
* - Chunk size limited by largest NFS data payload.
*
* Return values:
* %true: Write list is valid. @rctxt's xdr_stream is updated
* to point to the first byte past the Write list.
* %false: Write list is corrupt. @rctxt's xdr_stream is left
* in an unknown state.
*/
static bool xdr_check_write_list(struct svc_rdma_recv_ctxt *rctxt)
{
__be32 *p;
p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
if (!p)
return false;
if (!xdr_count_write_chunks(rctxt, p))
return false;
if (!pcl_alloc_write(rctxt, &rctxt->rc_write_pcl, p))
return false;
rctxt->rc_cur_result_payload = pcl_first_chunk(&rctxt->rc_write_pcl);
return true;
}
/* Sanity check the Reply chunk.
*
* Sanity checks:
* - Reply chunk does not overflow Receive buffer.
* - Chunk size limited by largest NFS data payload.
*
* Return values:
* %true: Reply chunk is valid. @rctxt's xdr_stream is updated
* to point to the first byte past the Reply chunk.
* %false: Reply chunk is corrupt. @rctxt's xdr_stream is left
* in an unknown state.
*/
static bool xdr_check_reply_chunk(struct svc_rdma_recv_ctxt *rctxt)
{
__be32 *p;
p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
if (!p)
return false;
if (!xdr_item_is_present(p))
return true;
if (!xdr_check_write_chunk(rctxt))
return false;
rctxt->rc_reply_pcl.cl_count = 1;
return pcl_alloc_write(rctxt, &rctxt->rc_reply_pcl, p);
}
/* RPC-over-RDMA Version One private extension: Remote Invalidation.
* Responder's choice: requester signals it can handle Send With
* Invalidate, and responder chooses one R_key to invalidate.
*
* If there is exactly one distinct R_key in the received transport
* header, set rc_inv_rkey to that R_key. Otherwise, set it to zero.
*/
static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma,
struct svc_rdma_recv_ctxt *ctxt)
{
struct svc_rdma_segment *segment;
struct svc_rdma_chunk *chunk;
u32 inv_rkey;
ctxt->rc_inv_rkey = 0;
if (!rdma->sc_snd_w_inv)
return;
inv_rkey = 0;
pcl_for_each_chunk(chunk, &ctxt->rc_call_pcl) {
pcl_for_each_segment(segment, chunk) {
if (inv_rkey == 0)
inv_rkey = segment->rs_handle;
else if (inv_rkey != segment->rs_handle)
return;
}
}
pcl_for_each_chunk(chunk, &ctxt->rc_read_pcl) {
pcl_for_each_segment(segment, chunk) {
if (inv_rkey == 0)
inv_rkey = segment->rs_handle;
else if (inv_rkey != segment->rs_handle)
return;
}
}
pcl_for_each_chunk(chunk, &ctxt->rc_write_pcl) {
pcl_for_each_segment(segment, chunk) {
if (inv_rkey == 0)
inv_rkey = segment->rs_handle;
else if (inv_rkey != segment->rs_handle)
return;
}
}
pcl_for_each_chunk(chunk, &ctxt->rc_reply_pcl) {
pcl_for_each_segment(segment, chunk) {
if (inv_rkey == 0)
inv_rkey = segment->rs_handle;
else if (inv_rkey != segment->rs_handle)
return;
}
}
ctxt->rc_inv_rkey = inv_rkey;
}
/**
* svc_rdma_xdr_decode_req - Decode the transport header
* @rq_arg: xdr_buf containing ingress RPC/RDMA message
* @rctxt: state of decoding
*
* On entry, xdr->head[0].iov_base points to first byte of the
* RPC-over-RDMA transport header.
*
* On successful exit, head[0] points to first byte past the
* RPC-over-RDMA header. For RDMA_MSG, this is the RPC message.
*
* The length of the RPC-over-RDMA header is returned.
*
* Assumptions:
* - The transport header is entirely contained in the head iovec.
*/
static int svc_rdma_xdr_decode_req(struct xdr_buf *rq_arg,
struct svc_rdma_recv_ctxt *rctxt)
{
__be32 *p, *rdma_argp;
unsigned int hdr_len;
rdma_argp = rq_arg->head[0].iov_base;
xdr_init_decode(&rctxt->rc_stream, rq_arg, rdma_argp, NULL);
p = xdr_inline_decode(&rctxt->rc_stream,
rpcrdma_fixed_maxsz * sizeof(*p));
if (unlikely(!p))
goto out_short;
p++;
if (*p != rpcrdma_version)
goto out_version;
p += 2;
rctxt->rc_msgtype = *p;
switch (rctxt->rc_msgtype) {
case rdma_msg:
break;
case rdma_nomsg:
break;
case rdma_done:
goto out_drop;
case rdma_error:
goto out_drop;
default:
goto out_proc;
}
if (!xdr_check_read_list(rctxt))
goto out_inval;
if (!xdr_check_write_list(rctxt))
goto out_inval;
if (!xdr_check_reply_chunk(rctxt))
goto out_inval;
rq_arg->head[0].iov_base = rctxt->rc_stream.p;
hdr_len = xdr_stream_pos(&rctxt->rc_stream);
rq_arg->head[0].iov_len -= hdr_len;
rq_arg->len -= hdr_len;
trace_svcrdma_decode_rqst(rctxt, rdma_argp, hdr_len);
return hdr_len;
out_short:
trace_svcrdma_decode_short_err(rctxt, rq_arg->len);
return -EINVAL;
out_version:
trace_svcrdma_decode_badvers_err(rctxt, rdma_argp);
return -EPROTONOSUPPORT;
out_drop:
trace_svcrdma_decode_drop_err(rctxt, rdma_argp);
return 0;
out_proc:
trace_svcrdma_decode_badproc_err(rctxt, rdma_argp);
return -EINVAL;
out_inval:
trace_svcrdma_decode_parse_err(rctxt, rdma_argp);
return -EINVAL;
}
static void svc_rdma_send_error(struct svcxprt_rdma *rdma,
struct svc_rdma_recv_ctxt *rctxt,
int status)
{
struct svc_rdma_send_ctxt *sctxt;
sctxt = svc_rdma_send_ctxt_get(rdma);
if (!sctxt)
return;
svc_rdma_send_error_msg(rdma, sctxt, rctxt, status);
}
/* By convention, backchannel calls arrive via rdma_msg type
* messages, and never populate the chunk lists. This makes
* the RPC/RDMA header small and fixed in size, so it is
* straightforward to check the RPC header's direction field.
*/
static bool svc_rdma_is_reverse_direction_reply(struct svc_xprt *xprt,
struct svc_rdma_recv_ctxt *rctxt)
{
__be32 *p = rctxt->rc_recv_buf;
if (!xprt->xpt_bc_xprt)
return false;
if (rctxt->rc_msgtype != rdma_msg)
return false;
if (!pcl_is_empty(&rctxt->rc_call_pcl))
return false;
if (!pcl_is_empty(&rctxt->rc_read_pcl))
return false;
if (!pcl_is_empty(&rctxt->rc_write_pcl))
return false;
if (!pcl_is_empty(&rctxt->rc_reply_pcl))
return false;
/* RPC call direction */
if (*(p + 8) == cpu_to_be32(RPC_CALL))
return false;
return true;
}
/* Finish constructing the RPC Call message in rqstp::rq_arg.
*
* The incoming RPC/RDMA message is an RDMA_MSG type message
* with a single Read chunk (only the upper layer data payload
* was conveyed via RDMA Read).
*/
static void svc_rdma_read_complete_one(struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *ctxt)
{
struct svc_rdma_chunk *chunk = pcl_first_chunk(&ctxt->rc_read_pcl);
struct xdr_buf *buf = &rqstp->rq_arg;
unsigned int length;
/* Split the Receive buffer between the head and tail
* buffers at Read chunk's position. XDR roundup of the
* chunk is not included in either the pagelist or in
* the tail.
*/
buf->tail[0].iov_base = buf->head[0].iov_base + chunk->ch_position;
buf->tail[0].iov_len = buf->head[0].iov_len - chunk->ch_position;
buf->head[0].iov_len = chunk->ch_position;
/* Read chunk may need XDR roundup (see RFC 8166, s. 3.4.5.2).
*
* If the client already rounded up the chunk length, the
* length does not change. Otherwise, the length of the page
* list is increased to include XDR round-up.
*
* Currently these chunks always start at page offset 0,
* thus the rounded-up length never crosses a page boundary.
*/
buf->pages = &rqstp->rq_pages[0];
length = xdr_align_size(chunk->ch_length);
buf->page_len = length;
buf->len += length;
buf->buflen += length;
}
/* Finish constructing the RPC Call message in rqstp::rq_arg.
*
* The incoming RPC/RDMA message is an RDMA_MSG type message
* with payload in multiple Read chunks and no PZRC.
*/
static void svc_rdma_read_complete_multiple(struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *ctxt)
{
struct xdr_buf *buf = &rqstp->rq_arg;
buf->len += ctxt->rc_readbytes;
buf->buflen += ctxt->rc_readbytes;
buf->head[0].iov_base = page_address(rqstp->rq_pages[0]);
buf->head[0].iov_len = min_t(size_t, PAGE_SIZE, ctxt->rc_readbytes);
buf->pages = &rqstp->rq_pages[1];
buf->page_len = ctxt->rc_readbytes - buf->head[0].iov_len;
}
/* Finish constructing the RPC Call message in rqstp::rq_arg.
*
* The incoming RPC/RDMA message is an RDMA_NOMSG type message
* (the RPC message body was conveyed via RDMA Read).
*/
static void svc_rdma_read_complete_pzrc(struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *ctxt)
{
struct xdr_buf *buf = &rqstp->rq_arg;
buf->len += ctxt->rc_readbytes;
buf->buflen += ctxt->rc_readbytes;
buf->head[0].iov_base = page_address(rqstp->rq_pages[0]);
buf->head[0].iov_len = min_t(size_t, PAGE_SIZE, ctxt->rc_readbytes);
buf->pages = &rqstp->rq_pages[1];
buf->page_len = ctxt->rc_readbytes - buf->head[0].iov_len;
}
static noinline void svc_rdma_read_complete(struct svc_rqst *rqstp,
struct svc_rdma_recv_ctxt *ctxt)
{
unsigned int i;
/* Transfer the Read chunk pages into @rqstp.rq_pages, replacing
* the rq_pages that were already allocated for this rqstp.
*/
release_pages(rqstp->rq_respages, ctxt->rc_page_count);
for (i = 0; i < ctxt->rc_page_count; i++)
rqstp->rq_pages[i] = ctxt->rc_pages[i];
/* Update @rqstp's result send buffer to start after the
* last page in the RDMA Read payload.
*/
rqstp->rq_respages = &rqstp->rq_pages[ctxt->rc_page_count];
rqstp->rq_next_page = rqstp->rq_respages + 1;
/* Prevent svc_rdma_recv_ctxt_put() from releasing the
* pages in ctxt::rc_pages a second time.
*/
ctxt->rc_page_count = 0;
/* Finish constructing the RPC Call message. The exact
* procedure for that depends on what kind of RPC/RDMA
* chunks were provided by the client.
*/
rqstp->rq_arg = ctxt->rc_saved_arg;
if (pcl_is_empty(&ctxt->rc_call_pcl)) {
if (ctxt->rc_read_pcl.cl_count == 1)
svc_rdma_read_complete_one(rqstp, ctxt);
else
svc_rdma_read_complete_multiple(rqstp, ctxt);
} else {
svc_rdma_read_complete_pzrc(rqstp, ctxt);
}
trace_svcrdma_read_finished(&ctxt->rc_cid);
}
/**
* svc_rdma_recvfrom - Receive an RPC call
* @rqstp: request structure into which to receive an RPC Call
*
* Returns:
* The positive number of bytes in the RPC Call message,
* %0 if there were no Calls ready to return,
* %-EINVAL if the Read chunk data is too large,
* %-ENOMEM if rdma_rw context pool was exhausted,
* %-ENOTCONN if posting failed (connection is lost),
* %-EIO if rdma_rw initialization failed (DMA mapping, etc).
*
* Called in a loop when XPT_DATA is set. XPT_DATA is cleared only
* when there are no remaining ctxt's to process.
*
* The next ctxt is removed from the "receive" lists.
*
* - If the ctxt completes a Receive, then construct the Call
* message from the contents of the Receive buffer.
*
* - If there are no Read chunks in this message, then finish
* assembling the Call message and return the number of bytes
* in the message.
*
* - If there are Read chunks in this message, post Read WRs to
* pull that payload. When the Read WRs complete, build the
* full message and return the number of bytes in it.
*/
int svc_rdma_recvfrom(struct svc_rqst *rqstp)
{
struct svc_xprt *xprt = rqstp->rq_xprt;
struct svcxprt_rdma *rdma_xprt =
container_of(xprt, struct svcxprt_rdma, sc_xprt);
struct svc_rdma_recv_ctxt *ctxt;
int ret;
/* Prevent svc_xprt_release() from releasing pages in rq_pages
* when returning 0 or an error.
*/
rqstp->rq_respages = rqstp->rq_pages;
rqstp->rq_next_page = rqstp->rq_respages;
rqstp->rq_xprt_ctxt = NULL;
spin_lock(&rdma_xprt->sc_rq_dto_lock);
ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_read_complete_q);
if (ctxt) {
list_del(&ctxt->rc_list);
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
svc_xprt_received(xprt);
svc_rdma_read_complete(rqstp, ctxt);
goto complete;
}
ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q);
if (ctxt)
list_del(&ctxt->rc_list);
else
/* No new incoming requests, terminate the loop */
clear_bit(XPT_DATA, &xprt->xpt_flags);
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
/* Unblock the transport for the next receive */
svc_xprt_received(xprt);
if (!ctxt)
return 0;
percpu_counter_inc(&svcrdma_stat_recv);
ib_dma_sync_single_for_cpu(rdma_xprt->sc_pd->device,
ctxt->rc_recv_sge.addr, ctxt->rc_byte_len,
DMA_FROM_DEVICE);
svc_rdma_build_arg_xdr(rqstp, ctxt);
ret = svc_rdma_xdr_decode_req(&rqstp->rq_arg, ctxt);
if (ret < 0)
goto out_err;
if (ret == 0)
goto out_drop;
if (svc_rdma_is_reverse_direction_reply(xprt, ctxt))
goto out_backchannel;
svc_rdma_get_inv_rkey(rdma_xprt, ctxt);
if (!pcl_is_empty(&ctxt->rc_read_pcl) ||
!pcl_is_empty(&ctxt->rc_call_pcl))
goto out_readlist;
complete:
rqstp->rq_xprt_ctxt = ctxt;
rqstp->rq_prot = IPPROTO_MAX;
svc_xprt_copy_addrs(rqstp, xprt);
set_bit(RQ_SECURE, &rqstp->rq_flags);
return rqstp->rq_arg.len;
out_err:
svc_rdma_send_error(rdma_xprt, ctxt, ret);
svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
return 0;
out_readlist:
/* This @rqstp is about to be recycled. Save the work
* already done constructing the Call message in rq_arg
* so it can be restored when the RDMA Reads have
* completed.
*/
ctxt->rc_saved_arg = rqstp->rq_arg;
ret = svc_rdma_process_read_list(rdma_xprt, rqstp, ctxt);
if (ret < 0) {
if (ret == -EINVAL)
svc_rdma_send_error(rdma_xprt, ctxt, ret);
svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
svc_xprt_deferred_close(xprt);
return ret;
}
return 0;
out_backchannel:
svc_rdma_handle_bc_reply(rqstp, ctxt);
out_drop:
svc_rdma_recv_ctxt_put(rdma_xprt, ctxt);
return 0;
}
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