swh:1:snp:49cd9498d6cccc5e78252c27dcb645bcf7bf0c91
Tip revision: 1291a0d5049dbc06baaaf66a9ff3f53db493b19b authored by Linus Torvalds on 18 December 2017, 02:59:59 UTC
Linux 4.15-rc4
Linux 4.15-rc4
Tip revision: 1291a0d
rpc_rdma.c
/*
* 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.
*/
/*
* rpc_rdma.c
*
* This file contains the guts of the RPC RDMA protocol, and
* does marshaling/unmarshaling, etc. It is also where interfacing
* to the Linux RPC framework lives.
*/
#include "xprt_rdma.h"
#include <linux/highmem.h>
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_TRANS
#endif
static const char transfertypes[][12] = {
"inline", /* no chunks */
"read list", /* some argument via rdma read */
"*read list", /* entire request via rdma read */
"write list", /* some result via rdma write */
"reply chunk" /* entire reply via rdma write */
};
/* Returns size of largest RPC-over-RDMA header in a Call message
*
* The largest Call header contains a full-size Read list and a
* minimal Reply chunk.
*/
static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
{
unsigned int size;
/* Fixed header fields and list discriminators */
size = RPCRDMA_HDRLEN_MIN;
/* Maximum Read list size */
maxsegs += 2; /* segment for head and tail buffers */
size = maxsegs * rpcrdma_readchunk_maxsz * sizeof(__be32);
/* Minimal Read chunk size */
size += sizeof(__be32); /* segment count */
size += rpcrdma_segment_maxsz * sizeof(__be32);
size += sizeof(__be32); /* list discriminator */
dprintk("RPC: %s: max call header size = %u\n",
__func__, size);
return size;
}
/* Returns size of largest RPC-over-RDMA header in a Reply message
*
* There is only one Write list or one Reply chunk per Reply
* message. The larger list is the Write list.
*/
static unsigned int rpcrdma_max_reply_header_size(unsigned int maxsegs)
{
unsigned int size;
/* Fixed header fields and list discriminators */
size = RPCRDMA_HDRLEN_MIN;
/* Maximum Write list size */
maxsegs += 2; /* segment for head and tail buffers */
size = sizeof(__be32); /* segment count */
size += maxsegs * rpcrdma_segment_maxsz * sizeof(__be32);
size += sizeof(__be32); /* list discriminator */
dprintk("RPC: %s: max reply header size = %u\n",
__func__, size);
return size;
}
void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
unsigned int maxsegs = ia->ri_max_segs;
ia->ri_max_inline_write = cdata->inline_wsize -
rpcrdma_max_call_header_size(maxsegs);
ia->ri_max_inline_read = cdata->inline_rsize -
rpcrdma_max_reply_header_size(maxsegs);
}
/* The client can send a request inline as long as the RPCRDMA header
* plus the RPC call fit under the transport's inline limit. If the
* combined call message size exceeds that limit, the client must use
* a Read chunk for this operation.
*
* A Read chunk is also required if sending the RPC call inline would
* exceed this device's max_sge limit.
*/
static bool rpcrdma_args_inline(struct rpcrdma_xprt *r_xprt,
struct rpc_rqst *rqst)
{
struct xdr_buf *xdr = &rqst->rq_snd_buf;
unsigned int count, remaining, offset;
if (xdr->len > r_xprt->rx_ia.ri_max_inline_write)
return false;
if (xdr->page_len) {
remaining = xdr->page_len;
offset = offset_in_page(xdr->page_base);
count = 0;
while (remaining) {
remaining -= min_t(unsigned int,
PAGE_SIZE - offset, remaining);
offset = 0;
if (++count > r_xprt->rx_ia.ri_max_send_sges)
return false;
}
}
return true;
}
/* The client can't know how large the actual reply will be. Thus it
* plans for the largest possible reply for that particular ULP
* operation. If the maximum combined reply message size exceeds that
* limit, the client must provide a write list or a reply chunk for
* this request.
*/
static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt,
struct rpc_rqst *rqst)
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
return rqst->rq_rcv_buf.buflen <= ia->ri_max_inline_read;
}
/* Split @vec on page boundaries into SGEs. FMR registers pages, not
* a byte range. Other modes coalesce these SGEs into a single MR
* when they can.
*
* Returns pointer to next available SGE, and bumps the total number
* of SGEs consumed.
*/
static struct rpcrdma_mr_seg *
rpcrdma_convert_kvec(struct kvec *vec, struct rpcrdma_mr_seg *seg,
unsigned int *n)
{
u32 remaining, page_offset;
char *base;
base = vec->iov_base;
page_offset = offset_in_page(base);
remaining = vec->iov_len;
while (remaining) {
seg->mr_page = NULL;
seg->mr_offset = base;
seg->mr_len = min_t(u32, PAGE_SIZE - page_offset, remaining);
remaining -= seg->mr_len;
base += seg->mr_len;
++seg;
++(*n);
page_offset = 0;
}
return seg;
}
/* Convert @xdrbuf into SGEs no larger than a page each. As they
* are registered, these SGEs are then coalesced into RDMA segments
* when the selected memreg mode supports it.
*
* Returns positive number of SGEs consumed, or a negative errno.
*/
static int
rpcrdma_convert_iovs(struct rpcrdma_xprt *r_xprt, struct xdr_buf *xdrbuf,
unsigned int pos, enum rpcrdma_chunktype type,
struct rpcrdma_mr_seg *seg)
{
unsigned long page_base;
unsigned int len, n;
struct page **ppages;
n = 0;
if (pos == 0)
seg = rpcrdma_convert_kvec(&xdrbuf->head[0], seg, &n);
len = xdrbuf->page_len;
ppages = xdrbuf->pages + (xdrbuf->page_base >> PAGE_SHIFT);
page_base = offset_in_page(xdrbuf->page_base);
while (len) {
if (unlikely(!*ppages)) {
/* XXX: Certain upper layer operations do
* not provide receive buffer pages.
*/
*ppages = alloc_page(GFP_ATOMIC);
if (!*ppages)
return -EAGAIN;
}
seg->mr_page = *ppages;
seg->mr_offset = (char *)page_base;
seg->mr_len = min_t(u32, PAGE_SIZE - page_base, len);
len -= seg->mr_len;
++ppages;
++seg;
++n;
page_base = 0;
}
/* When encoding a Read chunk, the tail iovec contains an
* XDR pad and may be omitted.
*/
if (type == rpcrdma_readch && r_xprt->rx_ia.ri_implicit_roundup)
goto out;
/* When encoding a Write chunk, some servers need to see an
* extra segment for non-XDR-aligned Write chunks. The upper
* layer provides space in the tail iovec that may be used
* for this purpose.
*/
if (type == rpcrdma_writech && r_xprt->rx_ia.ri_implicit_roundup)
goto out;
if (xdrbuf->tail[0].iov_len)
seg = rpcrdma_convert_kvec(&xdrbuf->tail[0], seg, &n);
out:
if (unlikely(n > RPCRDMA_MAX_SEGS))
return -EIO;
return n;
}
static inline int
encode_item_present(struct xdr_stream *xdr)
{
__be32 *p;
p = xdr_reserve_space(xdr, sizeof(*p));
if (unlikely(!p))
return -EMSGSIZE;
*p = xdr_one;
return 0;
}
static inline int
encode_item_not_present(struct xdr_stream *xdr)
{
__be32 *p;
p = xdr_reserve_space(xdr, sizeof(*p));
if (unlikely(!p))
return -EMSGSIZE;
*p = xdr_zero;
return 0;
}
static void
xdr_encode_rdma_segment(__be32 *iptr, struct rpcrdma_mw *mw)
{
*iptr++ = cpu_to_be32(mw->mw_handle);
*iptr++ = cpu_to_be32(mw->mw_length);
xdr_encode_hyper(iptr, mw->mw_offset);
}
static int
encode_rdma_segment(struct xdr_stream *xdr, struct rpcrdma_mw *mw)
{
__be32 *p;
p = xdr_reserve_space(xdr, 4 * sizeof(*p));
if (unlikely(!p))
return -EMSGSIZE;
xdr_encode_rdma_segment(p, mw);
return 0;
}
static int
encode_read_segment(struct xdr_stream *xdr, struct rpcrdma_mw *mw,
u32 position)
{
__be32 *p;
p = xdr_reserve_space(xdr, 6 * sizeof(*p));
if (unlikely(!p))
return -EMSGSIZE;
*p++ = xdr_one; /* Item present */
*p++ = cpu_to_be32(position);
xdr_encode_rdma_segment(p, mw);
return 0;
}
/* Register and XDR encode the Read list. Supports encoding a list of read
* segments that belong to a single read chunk.
*
* Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
*
* Read chunklist (a linked list):
* N elements, position P (same P for all chunks of same arg!):
* 1 - PHLOO - 1 - PHLOO - ... - 1 - PHLOO - 0
*
* Returns zero on success, or a negative errno if a failure occurred.
* @xdr is advanced to the next position in the stream.
*
* Only a single @pos value is currently supported.
*/
static noinline int
rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
struct rpc_rqst *rqst, enum rpcrdma_chunktype rtype)
{
struct xdr_stream *xdr = &req->rl_stream;
struct rpcrdma_mr_seg *seg;
struct rpcrdma_mw *mw;
unsigned int pos;
int nsegs;
pos = rqst->rq_snd_buf.head[0].iov_len;
if (rtype == rpcrdma_areadch)
pos = 0;
seg = req->rl_segments;
nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_snd_buf, pos,
rtype, seg);
if (nsegs < 0)
return nsegs;
do {
seg = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
false, &mw);
if (IS_ERR(seg))
return PTR_ERR(seg);
rpcrdma_push_mw(mw, &req->rl_registered);
if (encode_read_segment(xdr, mw, pos) < 0)
return -EMSGSIZE;
dprintk("RPC: %5u %s: pos %u %u@0x%016llx:0x%08x (%s)\n",
rqst->rq_task->tk_pid, __func__, pos,
mw->mw_length, (unsigned long long)mw->mw_offset,
mw->mw_handle, mw->mw_nents < nsegs ? "more" : "last");
r_xprt->rx_stats.read_chunk_count++;
nsegs -= mw->mw_nents;
} while (nsegs);
return 0;
}
/* Register and XDR encode the Write list. Supports encoding a list
* containing one array of plain segments that belong to a single
* write chunk.
*
* Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
*
* Write chunklist (a list of (one) counted array):
* N elements:
* 1 - N - HLOO - HLOO - ... - HLOO - 0
*
* Returns zero on success, or a negative errno if a failure occurred.
* @xdr is advanced to the next position in the stream.
*
* Only a single Write chunk is currently supported.
*/
static noinline int
rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
struct rpc_rqst *rqst, enum rpcrdma_chunktype wtype)
{
struct xdr_stream *xdr = &req->rl_stream;
struct rpcrdma_mr_seg *seg;
struct rpcrdma_mw *mw;
int nsegs, nchunks;
__be32 *segcount;
seg = req->rl_segments;
nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf,
rqst->rq_rcv_buf.head[0].iov_len,
wtype, seg);
if (nsegs < 0)
return nsegs;
if (encode_item_present(xdr) < 0)
return -EMSGSIZE;
segcount = xdr_reserve_space(xdr, sizeof(*segcount));
if (unlikely(!segcount))
return -EMSGSIZE;
/* Actual value encoded below */
nchunks = 0;
do {
seg = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
true, &mw);
if (IS_ERR(seg))
return PTR_ERR(seg);
rpcrdma_push_mw(mw, &req->rl_registered);
if (encode_rdma_segment(xdr, mw) < 0)
return -EMSGSIZE;
dprintk("RPC: %5u %s: %u@0x016%llx:0x%08x (%s)\n",
rqst->rq_task->tk_pid, __func__,
mw->mw_length, (unsigned long long)mw->mw_offset,
mw->mw_handle, mw->mw_nents < nsegs ? "more" : "last");
r_xprt->rx_stats.write_chunk_count++;
r_xprt->rx_stats.total_rdma_request += seg->mr_len;
nchunks++;
nsegs -= mw->mw_nents;
} while (nsegs);
/* Update count of segments in this Write chunk */
*segcount = cpu_to_be32(nchunks);
return 0;
}
/* Register and XDR encode the Reply chunk. Supports encoding an array
* of plain segments that belong to a single write (reply) chunk.
*
* Encoding key for single-list chunks (HLOO = Handle32 Length32 Offset64):
*
* Reply chunk (a counted array):
* N elements:
* 1 - N - HLOO - HLOO - ... - HLOO
*
* Returns zero on success, or a negative errno if a failure occurred.
* @xdr is advanced to the next position in the stream.
*/
static noinline int
rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
struct rpc_rqst *rqst, enum rpcrdma_chunktype wtype)
{
struct xdr_stream *xdr = &req->rl_stream;
struct rpcrdma_mr_seg *seg;
struct rpcrdma_mw *mw;
int nsegs, nchunks;
__be32 *segcount;
seg = req->rl_segments;
nsegs = rpcrdma_convert_iovs(r_xprt, &rqst->rq_rcv_buf, 0, wtype, seg);
if (nsegs < 0)
return nsegs;
if (encode_item_present(xdr) < 0)
return -EMSGSIZE;
segcount = xdr_reserve_space(xdr, sizeof(*segcount));
if (unlikely(!segcount))
return -EMSGSIZE;
/* Actual value encoded below */
nchunks = 0;
do {
seg = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs,
true, &mw);
if (IS_ERR(seg))
return PTR_ERR(seg);
rpcrdma_push_mw(mw, &req->rl_registered);
if (encode_rdma_segment(xdr, mw) < 0)
return -EMSGSIZE;
dprintk("RPC: %5u %s: %u@0x%016llx:0x%08x (%s)\n",
rqst->rq_task->tk_pid, __func__,
mw->mw_length, (unsigned long long)mw->mw_offset,
mw->mw_handle, mw->mw_nents < nsegs ? "more" : "last");
r_xprt->rx_stats.reply_chunk_count++;
r_xprt->rx_stats.total_rdma_request += seg->mr_len;
nchunks++;
nsegs -= mw->mw_nents;
} while (nsegs);
/* Update count of segments in the Reply chunk */
*segcount = cpu_to_be32(nchunks);
return 0;
}
/**
* rpcrdma_unmap_sendctx - DMA-unmap Send buffers
* @sc: sendctx containing SGEs to unmap
*
*/
void
rpcrdma_unmap_sendctx(struct rpcrdma_sendctx *sc)
{
struct rpcrdma_ia *ia = &sc->sc_xprt->rx_ia;
struct ib_sge *sge;
unsigned int count;
dprintk("RPC: %s: unmapping %u sges for sc=%p\n",
__func__, sc->sc_unmap_count, sc);
/* The first two SGEs contain the transport header and
* the inline buffer. These are always left mapped so
* they can be cheaply re-used.
*/
sge = &sc->sc_sges[2];
for (count = sc->sc_unmap_count; count; ++sge, --count)
ib_dma_unmap_page(ia->ri_device,
sge->addr, sge->length, DMA_TO_DEVICE);
if (test_and_clear_bit(RPCRDMA_REQ_F_TX_RESOURCES, &sc->sc_req->rl_flags)) {
smp_mb__after_atomic();
wake_up_bit(&sc->sc_req->rl_flags, RPCRDMA_REQ_F_TX_RESOURCES);
}
}
/* Prepare an SGE for the RPC-over-RDMA transport header.
*/
static bool
rpcrdma_prepare_hdr_sge(struct rpcrdma_ia *ia, struct rpcrdma_req *req,
u32 len)
{
struct rpcrdma_sendctx *sc = req->rl_sendctx;
struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
struct ib_sge *sge = sc->sc_sges;
if (!rpcrdma_dma_map_regbuf(ia, rb))
goto out_regbuf;
sge->addr = rdmab_addr(rb);
sge->length = len;
sge->lkey = rdmab_lkey(rb);
ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr,
sge->length, DMA_TO_DEVICE);
sc->sc_wr.num_sge++;
return true;
out_regbuf:
pr_err("rpcrdma: failed to DMA map a Send buffer\n");
return false;
}
/* Prepare the Send SGEs. The head and tail iovec, and each entry
* in the page list, gets its own SGE.
*/
static bool
rpcrdma_prepare_msg_sges(struct rpcrdma_ia *ia, struct rpcrdma_req *req,
struct xdr_buf *xdr, enum rpcrdma_chunktype rtype)
{
struct rpcrdma_sendctx *sc = req->rl_sendctx;
unsigned int sge_no, page_base, len, remaining;
struct rpcrdma_regbuf *rb = req->rl_sendbuf;
struct ib_device *device = ia->ri_device;
struct ib_sge *sge = sc->sc_sges;
u32 lkey = ia->ri_pd->local_dma_lkey;
struct page *page, **ppages;
/* The head iovec is straightforward, as it is already
* DMA-mapped. Sync the content that has changed.
*/
if (!rpcrdma_dma_map_regbuf(ia, rb))
goto out_regbuf;
sge_no = 1;
sge[sge_no].addr = rdmab_addr(rb);
sge[sge_no].length = xdr->head[0].iov_len;
sge[sge_no].lkey = rdmab_lkey(rb);
ib_dma_sync_single_for_device(rdmab_device(rb), sge[sge_no].addr,
sge[sge_no].length, DMA_TO_DEVICE);
/* If there is a Read chunk, the page list is being handled
* via explicit RDMA, and thus is skipped here. However, the
* tail iovec may include an XDR pad for the page list, as
* well as additional content, and may not reside in the
* same page as the head iovec.
*/
if (rtype == rpcrdma_readch) {
len = xdr->tail[0].iov_len;
/* Do not include the tail if it is only an XDR pad */
if (len < 4)
goto out;
page = virt_to_page(xdr->tail[0].iov_base);
page_base = offset_in_page(xdr->tail[0].iov_base);
/* If the content in the page list is an odd length,
* xdr_write_pages() has added a pad at the beginning
* of the tail iovec. Force the tail's non-pad content
* to land at the next XDR position in the Send message.
*/
page_base += len & 3;
len -= len & 3;
goto map_tail;
}
/* If there is a page list present, temporarily DMA map
* and prepare an SGE for each page to be sent.
*/
if (xdr->page_len) {
ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
page_base = offset_in_page(xdr->page_base);
remaining = xdr->page_len;
while (remaining) {
sge_no++;
if (sge_no > RPCRDMA_MAX_SEND_SGES - 2)
goto out_mapping_overflow;
len = min_t(u32, PAGE_SIZE - page_base, remaining);
sge[sge_no].addr = ib_dma_map_page(device, *ppages,
page_base, len,
DMA_TO_DEVICE);
if (ib_dma_mapping_error(device, sge[sge_no].addr))
goto out_mapping_err;
sge[sge_no].length = len;
sge[sge_no].lkey = lkey;
sc->sc_unmap_count++;
ppages++;
remaining -= len;
page_base = 0;
}
}
/* The tail iovec is not always constructed in the same
* page where the head iovec resides (see, for example,
* gss_wrap_req_priv). To neatly accommodate that case,
* DMA map it separately.
*/
if (xdr->tail[0].iov_len) {
page = virt_to_page(xdr->tail[0].iov_base);
page_base = offset_in_page(xdr->tail[0].iov_base);
len = xdr->tail[0].iov_len;
map_tail:
sge_no++;
sge[sge_no].addr = ib_dma_map_page(device, page,
page_base, len,
DMA_TO_DEVICE);
if (ib_dma_mapping_error(device, sge[sge_no].addr))
goto out_mapping_err;
sge[sge_no].length = len;
sge[sge_no].lkey = lkey;
sc->sc_unmap_count++;
}
out:
sc->sc_wr.num_sge += sge_no;
if (sc->sc_unmap_count)
__set_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags);
return true;
out_regbuf:
pr_err("rpcrdma: failed to DMA map a Send buffer\n");
return false;
out_mapping_overflow:
rpcrdma_unmap_sendctx(sc);
pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no);
return false;
out_mapping_err:
rpcrdma_unmap_sendctx(sc);
pr_err("rpcrdma: Send mapping error\n");
return false;
}
/**
* rpcrdma_prepare_send_sges - Construct SGEs for a Send WR
* @r_xprt: controlling transport
* @req: context of RPC Call being marshalled
* @hdrlen: size of transport header, in bytes
* @xdr: xdr_buf containing RPC Call
* @rtype: chunk type being encoded
*
* Returns 0 on success; otherwise a negative errno is returned.
*/
int
rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_req *req, u32 hdrlen,
struct xdr_buf *xdr, enum rpcrdma_chunktype rtype)
{
req->rl_sendctx = rpcrdma_sendctx_get_locked(&r_xprt->rx_buf);
if (!req->rl_sendctx)
return -ENOBUFS;
req->rl_sendctx->sc_wr.num_sge = 0;
req->rl_sendctx->sc_unmap_count = 0;
req->rl_sendctx->sc_req = req;
__clear_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags);
if (!rpcrdma_prepare_hdr_sge(&r_xprt->rx_ia, req, hdrlen))
return -EIO;
if (rtype != rpcrdma_areadch)
if (!rpcrdma_prepare_msg_sges(&r_xprt->rx_ia, req, xdr, rtype))
return -EIO;
return 0;
}
/**
* rpcrdma_marshal_req - Marshal and send one RPC request
* @r_xprt: controlling transport
* @rqst: RPC request to be marshaled
*
* For the RPC in "rqst", this function:
* - Chooses the transfer mode (eg., RDMA_MSG or RDMA_NOMSG)
* - Registers Read, Write, and Reply chunks
* - Constructs the transport header
* - Posts a Send WR to send the transport header and request
*
* Returns:
* %0 if the RPC was sent successfully,
* %-ENOTCONN if the connection was lost,
* %-EAGAIN if not enough pages are available for on-demand reply buffer,
* %-ENOBUFS if no MRs are available to register chunks,
* %-EMSGSIZE if the transport header is too small,
* %-EIO if a permanent problem occurred while marshaling.
*/
int
rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
{
struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
struct xdr_stream *xdr = &req->rl_stream;
enum rpcrdma_chunktype rtype, wtype;
bool ddp_allowed;
__be32 *p;
int ret;
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
if (test_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state))
return rpcrdma_bc_marshal_reply(rqst);
#endif
rpcrdma_set_xdrlen(&req->rl_hdrbuf, 0);
xdr_init_encode(xdr, &req->rl_hdrbuf,
req->rl_rdmabuf->rg_base);
/* Fixed header fields */
ret = -EMSGSIZE;
p = xdr_reserve_space(xdr, 4 * sizeof(*p));
if (!p)
goto out_err;
*p++ = rqst->rq_xid;
*p++ = rpcrdma_version;
*p++ = cpu_to_be32(r_xprt->rx_buf.rb_max_requests);
/* When the ULP employs a GSS flavor that guarantees integrity
* or privacy, direct data placement of individual data items
* is not allowed.
*/
ddp_allowed = !(rqst->rq_cred->cr_auth->au_flags &
RPCAUTH_AUTH_DATATOUCH);
/*
* Chunks needed for results?
*
* o If the expected result is under the inline threshold, all ops
* return as inline.
* o Large read ops return data as write chunk(s), header as
* inline.
* o Large non-read ops return as a single reply chunk.
*/
if (rpcrdma_results_inline(r_xprt, rqst))
wtype = rpcrdma_noch;
else if (ddp_allowed && rqst->rq_rcv_buf.flags & XDRBUF_READ)
wtype = rpcrdma_writech;
else
wtype = rpcrdma_replych;
/*
* Chunks needed for arguments?
*
* o If the total request is under the inline threshold, all ops
* are sent as inline.
* o Large write ops transmit data as read chunk(s), header as
* inline.
* o Large non-write ops are sent with the entire message as a
* single read chunk (protocol 0-position special case).
*
* This assumes that the upper layer does not present a request
* that both has a data payload, and whose non-data arguments
* by themselves are larger than the inline threshold.
*/
if (rpcrdma_args_inline(r_xprt, rqst)) {
*p++ = rdma_msg;
rtype = rpcrdma_noch;
} else if (ddp_allowed && rqst->rq_snd_buf.flags & XDRBUF_WRITE) {
*p++ = rdma_msg;
rtype = rpcrdma_readch;
} else {
r_xprt->rx_stats.nomsg_call_count++;
*p++ = rdma_nomsg;
rtype = rpcrdma_areadch;
}
/* This implementation supports the following combinations
* of chunk lists in one RPC-over-RDMA Call message:
*
* - Read list
* - Write list
* - Reply chunk
* - Read list + Reply chunk
*
* It might not yet support the following combinations:
*
* - Read list + Write list
*
* It does not support the following combinations:
*
* - Write list + Reply chunk
* - Read list + Write list + Reply chunk
*
* This implementation supports only a single chunk in each
* Read or Write list. Thus for example the client cannot
* send a Call message with a Position Zero Read chunk and a
* regular Read chunk at the same time.
*/
if (rtype != rpcrdma_noch) {
ret = rpcrdma_encode_read_list(r_xprt, req, rqst, rtype);
if (ret)
goto out_err;
}
ret = encode_item_not_present(xdr);
if (ret)
goto out_err;
if (wtype == rpcrdma_writech) {
ret = rpcrdma_encode_write_list(r_xprt, req, rqst, wtype);
if (ret)
goto out_err;
}
ret = encode_item_not_present(xdr);
if (ret)
goto out_err;
if (wtype != rpcrdma_replych)
ret = encode_item_not_present(xdr);
else
ret = rpcrdma_encode_reply_chunk(r_xprt, req, rqst, wtype);
if (ret)
goto out_err;
dprintk("RPC: %5u %s: %s/%s: hdrlen %u rpclen\n",
rqst->rq_task->tk_pid, __func__,
transfertypes[rtype], transfertypes[wtype],
xdr_stream_pos(xdr));
ret = rpcrdma_prepare_send_sges(r_xprt, req, xdr_stream_pos(xdr),
&rqst->rq_snd_buf, rtype);
if (ret)
goto out_err;
return 0;
out_err:
if (ret != -ENOBUFS) {
pr_err("rpcrdma: header marshaling failed (%d)\n", ret);
r_xprt->rx_stats.failed_marshal_count++;
}
return ret;
}
/**
* rpcrdma_inline_fixup - Scatter inline received data into rqst's iovecs
* @rqst: controlling RPC request
* @srcp: points to RPC message payload in receive buffer
* @copy_len: remaining length of receive buffer content
* @pad: Write chunk pad bytes needed (zero for pure inline)
*
* The upper layer has set the maximum number of bytes it can
* receive in each component of rq_rcv_buf. These values are set in
* the head.iov_len, page_len, tail.iov_len, and buflen fields.
*
* Unlike the TCP equivalent (xdr_partial_copy_from_skb), in
* many cases this function simply updates iov_base pointers in
* rq_rcv_buf to point directly to the received reply data, to
* avoid copying reply data.
*
* Returns the count of bytes which had to be memcopied.
*/
static unsigned long
rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
{
unsigned long fixup_copy_count;
int i, npages, curlen;
char *destp;
struct page **ppages;
int page_base;
/* The head iovec is redirected to the RPC reply message
* in the receive buffer, to avoid a memcopy.
*/
rqst->rq_rcv_buf.head[0].iov_base = srcp;
rqst->rq_private_buf.head[0].iov_base = srcp;
/* The contents of the receive buffer that follow
* head.iov_len bytes are copied into the page list.
*/
curlen = rqst->rq_rcv_buf.head[0].iov_len;
if (curlen > copy_len)
curlen = copy_len;
dprintk("RPC: %s: srcp 0x%p len %d hdrlen %d\n",
__func__, srcp, copy_len, curlen);
srcp += curlen;
copy_len -= curlen;
ppages = rqst->rq_rcv_buf.pages +
(rqst->rq_rcv_buf.page_base >> PAGE_SHIFT);
page_base = offset_in_page(rqst->rq_rcv_buf.page_base);
fixup_copy_count = 0;
if (copy_len && rqst->rq_rcv_buf.page_len) {
int pagelist_len;
pagelist_len = rqst->rq_rcv_buf.page_len;
if (pagelist_len > copy_len)
pagelist_len = copy_len;
npages = PAGE_ALIGN(page_base + pagelist_len) >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
curlen = PAGE_SIZE - page_base;
if (curlen > pagelist_len)
curlen = pagelist_len;
dprintk("RPC: %s: page %d"
" srcp 0x%p len %d curlen %d\n",
__func__, i, srcp, copy_len, curlen);
destp = kmap_atomic(ppages[i]);
memcpy(destp + page_base, srcp, curlen);
flush_dcache_page(ppages[i]);
kunmap_atomic(destp);
srcp += curlen;
copy_len -= curlen;
fixup_copy_count += curlen;
pagelist_len -= curlen;
if (!pagelist_len)
break;
page_base = 0;
}
/* Implicit padding for the last segment in a Write
* chunk is inserted inline at the front of the tail
* iovec. The upper layer ignores the content of
* the pad. Simply ensure inline content in the tail
* that follows the Write chunk is properly aligned.
*/
if (pad)
srcp -= pad;
}
/* The tail iovec is redirected to the remaining data
* in the receive buffer, to avoid a memcopy.
*/
if (copy_len || pad) {
rqst->rq_rcv_buf.tail[0].iov_base = srcp;
rqst->rq_private_buf.tail[0].iov_base = srcp;
}
return fixup_copy_count;
}
/* Caller must guarantee @rep remains stable during this call.
*/
static void
rpcrdma_mark_remote_invalidation(struct list_head *mws,
struct rpcrdma_rep *rep)
{
struct rpcrdma_mw *mw;
if (!(rep->rr_wc_flags & IB_WC_WITH_INVALIDATE))
return;
list_for_each_entry(mw, mws, mw_list)
if (mw->mw_handle == rep->rr_inv_rkey) {
mw->mw_flags = RPCRDMA_MW_F_RI;
break; /* only one invalidated MR per RPC */
}
}
/* 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
rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
{
struct xdr_stream *xdr = &rep->rr_stream;
__be32 *p;
if (rep->rr_proc != rdma_msg)
return false;
/* Peek at stream contents without advancing. */
p = xdr_inline_decode(xdr, 0);
/* Chunk lists */
if (*p++ != xdr_zero)
return false;
if (*p++ != xdr_zero)
return false;
if (*p++ != xdr_zero)
return false;
/* RPC header */
if (*p++ != rep->rr_xid)
return false;
if (*p != cpu_to_be32(RPC_CALL))
return false;
/* Now that we are sure this is a backchannel call,
* advance to the RPC header.
*/
p = xdr_inline_decode(xdr, 3 * sizeof(*p));
if (unlikely(!p))
goto out_short;
rpcrdma_bc_receive_call(r_xprt, rep);
return true;
out_short:
pr_warn("RPC/RDMA short backward direction call\n");
if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, rep))
xprt_disconnect_done(&r_xprt->rx_xprt);
return true;
}
#else /* CONFIG_SUNRPC_BACKCHANNEL */
{
return false;
}
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
static int decode_rdma_segment(struct xdr_stream *xdr, u32 *length)
{
__be32 *p;
p = xdr_inline_decode(xdr, 4 * sizeof(*p));
if (unlikely(!p))
return -EIO;
ifdebug(FACILITY) {
u64 offset;
u32 handle;
handle = be32_to_cpup(p++);
*length = be32_to_cpup(p++);
xdr_decode_hyper(p, &offset);
dprintk("RPC: %s: segment %u@0x%016llx:0x%08x\n",
__func__, *length, (unsigned long long)offset,
handle);
} else {
*length = be32_to_cpup(p + 1);
}
return 0;
}
static int decode_write_chunk(struct xdr_stream *xdr, u32 *length)
{
u32 segcount, seglength;
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
*length = 0;
segcount = be32_to_cpup(p);
while (segcount--) {
if (decode_rdma_segment(xdr, &seglength))
return -EIO;
*length += seglength;
}
dprintk("RPC: %s: segcount=%u, %u bytes\n",
__func__, be32_to_cpup(p), *length);
return 0;
}
/* In RPC-over-RDMA Version One replies, a Read list is never
* expected. This decoder is a stub that returns an error if
* a Read list is present.
*/
static int decode_read_list(struct xdr_stream *xdr)
{
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
if (unlikely(*p != xdr_zero))
return -EIO;
return 0;
}
/* Supports only one Write chunk in the Write list
*/
static int decode_write_list(struct xdr_stream *xdr, u32 *length)
{
u32 chunklen;
bool first;
__be32 *p;
*length = 0;
first = true;
do {
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
if (*p == xdr_zero)
break;
if (!first)
return -EIO;
if (decode_write_chunk(xdr, &chunklen))
return -EIO;
*length += chunklen;
first = false;
} while (true);
return 0;
}
static int decode_reply_chunk(struct xdr_stream *xdr, u32 *length)
{
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
*length = 0;
if (*p != xdr_zero)
if (decode_write_chunk(xdr, length))
return -EIO;
return 0;
}
static int
rpcrdma_decode_msg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
struct rpc_rqst *rqst)
{
struct xdr_stream *xdr = &rep->rr_stream;
u32 writelist, replychunk, rpclen;
char *base;
/* Decode the chunk lists */
if (decode_read_list(xdr))
return -EIO;
if (decode_write_list(xdr, &writelist))
return -EIO;
if (decode_reply_chunk(xdr, &replychunk))
return -EIO;
/* RDMA_MSG sanity checks */
if (unlikely(replychunk))
return -EIO;
/* Build the RPC reply's Payload stream in rqst->rq_rcv_buf */
base = (char *)xdr_inline_decode(xdr, 0);
rpclen = xdr_stream_remaining(xdr);
r_xprt->rx_stats.fixup_copy_count +=
rpcrdma_inline_fixup(rqst, base, rpclen, writelist & 3);
r_xprt->rx_stats.total_rdma_reply += writelist;
return rpclen + xdr_align_size(writelist);
}
static noinline int
rpcrdma_decode_nomsg(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
{
struct xdr_stream *xdr = &rep->rr_stream;
u32 writelist, replychunk;
/* Decode the chunk lists */
if (decode_read_list(xdr))
return -EIO;
if (decode_write_list(xdr, &writelist))
return -EIO;
if (decode_reply_chunk(xdr, &replychunk))
return -EIO;
/* RDMA_NOMSG sanity checks */
if (unlikely(writelist))
return -EIO;
if (unlikely(!replychunk))
return -EIO;
/* Reply chunk buffer already is the reply vector */
r_xprt->rx_stats.total_rdma_reply += replychunk;
return replychunk;
}
static noinline int
rpcrdma_decode_error(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep,
struct rpc_rqst *rqst)
{
struct xdr_stream *xdr = &rep->rr_stream;
__be32 *p;
p = xdr_inline_decode(xdr, sizeof(*p));
if (unlikely(!p))
return -EIO;
switch (*p) {
case err_vers:
p = xdr_inline_decode(xdr, 2 * sizeof(*p));
if (!p)
break;
dprintk("RPC: %5u: %s: server reports version error (%u-%u)\n",
rqst->rq_task->tk_pid, __func__,
be32_to_cpup(p), be32_to_cpu(*(p + 1)));
break;
case err_chunk:
dprintk("RPC: %5u: %s: server reports header decoding error\n",
rqst->rq_task->tk_pid, __func__);
break;
default:
dprintk("RPC: %5u: %s: server reports unrecognized error %d\n",
rqst->rq_task->tk_pid, __func__, be32_to_cpup(p));
}
r_xprt->rx_stats.bad_reply_count++;
return -EREMOTEIO;
}
/* Perform XID lookup, reconstruction of the RPC reply, and
* RPC completion while holding the transport lock to ensure
* the rep, rqst, and rq_task pointers remain stable.
*/
void rpcrdma_complete_rqst(struct rpcrdma_rep *rep)
{
struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
struct rpc_rqst *rqst = rep->rr_rqst;
unsigned long cwnd;
int status;
xprt->reestablish_timeout = 0;
switch (rep->rr_proc) {
case rdma_msg:
status = rpcrdma_decode_msg(r_xprt, rep, rqst);
break;
case rdma_nomsg:
status = rpcrdma_decode_nomsg(r_xprt, rep);
break;
case rdma_error:
status = rpcrdma_decode_error(r_xprt, rep, rqst);
break;
default:
status = -EIO;
}
if (status < 0)
goto out_badheader;
out:
spin_lock(&xprt->recv_lock);
cwnd = xprt->cwnd;
xprt->cwnd = r_xprt->rx_buf.rb_credits << RPC_CWNDSHIFT;
if (xprt->cwnd > cwnd)
xprt_release_rqst_cong(rqst->rq_task);
xprt_complete_rqst(rqst->rq_task, status);
xprt_unpin_rqst(rqst);
spin_unlock(&xprt->recv_lock);
return;
/* If the incoming reply terminated a pending RPC, the next
* RPC call will post a replacement receive buffer as it is
* being marshaled.
*/
out_badheader:
dprintk("RPC: %5u %s: invalid rpcrdma reply (type %u)\n",
rqst->rq_task->tk_pid, __func__, be32_to_cpu(rep->rr_proc));
r_xprt->rx_stats.bad_reply_count++;
status = -EIO;
goto out;
}
void rpcrdma_release_rqst(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
{
/* Invalidate and unmap the data payloads before waking
* the waiting application. This guarantees the memory
* regions are properly fenced from the server before the
* application accesses the data. It also ensures proper
* send flow control: waking the next RPC waits until this
* RPC has relinquished all its Send Queue entries.
*/
if (!list_empty(&req->rl_registered))
r_xprt->rx_ia.ri_ops->ro_unmap_sync(r_xprt,
&req->rl_registered);
/* Ensure that any DMA mapped pages associated with
* the Send of the RPC Call have been unmapped before
* allowing the RPC to complete. This protects argument
* memory not controlled by the RPC client from being
* re-used before we're done with it.
*/
if (test_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags)) {
r_xprt->rx_stats.reply_waits_for_send++;
out_of_line_wait_on_bit(&req->rl_flags,
RPCRDMA_REQ_F_TX_RESOURCES,
bit_wait,
TASK_UNINTERRUPTIBLE);
}
}
/* Reply handling runs in the poll worker thread. Anything that
* might wait is deferred to a separate workqueue.
*/
void rpcrdma_deferred_completion(struct work_struct *work)
{
struct rpcrdma_rep *rep =
container_of(work, struct rpcrdma_rep, rr_work);
struct rpcrdma_req *req = rpcr_to_rdmar(rep->rr_rqst);
rpcrdma_mark_remote_invalidation(&req->rl_registered, rep);
rpcrdma_release_rqst(rep->rr_rxprt, req);
rpcrdma_complete_rqst(rep);
}
/* Process received RPC/RDMA messages.
*
* Errors must result in the RPC task either being awakened, or
* allowed to timeout, to discover the errors at that time.
*/
void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
{
struct rpcrdma_xprt *r_xprt = rep->rr_rxprt;
struct rpc_xprt *xprt = &r_xprt->rx_xprt;
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_req *req;
struct rpc_rqst *rqst;
u32 credits;
__be32 *p;
dprintk("RPC: %s: incoming rep %p\n", __func__, rep);
if (rep->rr_hdrbuf.head[0].iov_len == 0)
goto out_badstatus;
xdr_init_decode(&rep->rr_stream, &rep->rr_hdrbuf,
rep->rr_hdrbuf.head[0].iov_base);
/* Fixed transport header fields */
p = xdr_inline_decode(&rep->rr_stream, 4 * sizeof(*p));
if (unlikely(!p))
goto out_shortreply;
rep->rr_xid = *p++;
rep->rr_vers = *p++;
credits = be32_to_cpu(*p++);
rep->rr_proc = *p++;
if (rep->rr_vers != rpcrdma_version)
goto out_badversion;
if (rpcrdma_is_bcall(r_xprt, rep))
return;
/* Match incoming rpcrdma_rep to an rpcrdma_req to
* get context for handling any incoming chunks.
*/
spin_lock(&xprt->recv_lock);
rqst = xprt_lookup_rqst(xprt, rep->rr_xid);
if (!rqst)
goto out_norqst;
xprt_pin_rqst(rqst);
if (credits == 0)
credits = 1; /* don't deadlock */
else if (credits > buf->rb_max_requests)
credits = buf->rb_max_requests;
buf->rb_credits = credits;
spin_unlock(&xprt->recv_lock);
req = rpcr_to_rdmar(rqst);
req->rl_reply = rep;
rep->rr_rqst = rqst;
clear_bit(RPCRDMA_REQ_F_PENDING, &req->rl_flags);
dprintk("RPC: %s: reply %p completes request %p (xid 0x%08x)\n",
__func__, rep, req, be32_to_cpu(rep->rr_xid));
queue_work_on(req->rl_cpu, rpcrdma_receive_wq, &rep->rr_work);
return;
out_badstatus:
rpcrdma_recv_buffer_put(rep);
if (r_xprt->rx_ep.rep_connected == 1) {
r_xprt->rx_ep.rep_connected = -EIO;
rpcrdma_conn_func(&r_xprt->rx_ep);
}
return;
out_badversion:
dprintk("RPC: %s: invalid version %d\n",
__func__, be32_to_cpu(rep->rr_vers));
goto repost;
/* The RPC transaction has already been terminated, or the header
* is corrupt.
*/
out_norqst:
spin_unlock(&xprt->recv_lock);
dprintk("RPC: %s: no match for incoming xid 0x%08x\n",
__func__, be32_to_cpu(rep->rr_xid));
goto repost;
out_shortreply:
dprintk("RPC: %s: short/invalid reply\n", __func__);
/* If no pending RPC transaction was matched, post a replacement
* receive buffer before returning.
*/
repost:
r_xprt->rx_stats.bad_reply_count++;
if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, rep))
rpcrdma_recv_buffer_put(rep);
}
