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e77340e003
linux/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
Chuck Lever e77340e003 svcrdma: Improve Read chunk sanity checking 
Identify malformed transport headers and unsupported chunk
combinations as early as possible.

- Reject RPC-over-RDMA messages that contain more than one Read chunk,
  since this implementation currently does not support more than one
  per RPC transaction.

- Ensure that segment lengths are not crazy.

- Remove the segment count check. With a 1KB inline threshold, the
  largest number of Read segments that can be conveyed is about 40
  (for a RDMA_NOMSG Call message). This is nowhere near
  RPCSVC_MAXPAGES. As far as I can tell, that was just a sanity
  check and does not enforce an implementation limit.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2017-06-28 14:21:43 -04:00

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/*
* Copyright (c) 2016, 2017 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 <tom@opengridcomputing.com>
*/
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/spinlock.h>
#include <asm/unaligned.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#include <linux/sunrpc/svc_rdma.h>
#define RPCDBG_FACILITY RPCDBG_SVCXPRT
/*
* Replace the pages in the rq_argpages array with the pages from the SGE in
* the RDMA_RECV completion. The SGL should contain full pages up until the
* last one.
*/
static void rdma_build_arg_xdr(struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *ctxt,
u32 byte_count)
{
struct rpcrdma_msg *rmsgp;
struct page *page;
u32 bc;
int sge_no;
/* Swap the page in the SGE with the page in argpages */
page = ctxt->pages[0];
put_page(rqstp->rq_pages[0]);
rqstp->rq_pages[0] = page;
/* Set up the XDR head */
rqstp->rq_arg.head[0].iov_base = page_address(page);
rqstp->rq_arg.head[0].iov_len =
min_t(size_t, byte_count, ctxt->sge[0].length);
rqstp->rq_arg.len = byte_count;
rqstp->rq_arg.buflen = byte_count;
/* Compute bytes past head in the SGL */
bc = byte_count - rqstp->rq_arg.head[0].iov_len;
/* If data remains, store it in the pagelist */
rqstp->rq_arg.page_len = bc;
rqstp->rq_arg.page_base = 0;
/* RDMA_NOMSG: RDMA READ data should land just after RDMA RECV data */
rmsgp = (struct rpcrdma_msg *)rqstp->rq_arg.head[0].iov_base;
if (rmsgp->rm_type == rdma_nomsg)
rqstp->rq_arg.pages = &rqstp->rq_pages[0];
else
rqstp->rq_arg.pages = &rqstp->rq_pages[1];
sge_no = 1;
while (bc && sge_no < ctxt->count) {
page = ctxt->pages[sge_no];
put_page(rqstp->rq_pages[sge_no]);
rqstp->rq_pages[sge_no] = page;
bc -= min_t(u32, bc, ctxt->sge[sge_no].length);
rqstp->rq_arg.buflen += ctxt->sge[sge_no].length;
sge_no++;
}
rqstp->rq_respages = &rqstp->rq_pages[sge_no];
rqstp->rq_next_page = rqstp->rq_respages + 1;
/* If not all pages were used from the SGL, free the remaining ones */
bc = sge_no;
while (sge_no < ctxt->count) {
page = ctxt->pages[sge_no++];
put_page(page);
}
ctxt->count = bc;
/* Set up tail */
rqstp->rq_arg.tail[0].iov_base = NULL;
rqstp->rq_arg.tail[0].iov_len = 0;
}
/* This accommodates the largest possible Position-Zero
* Read chunk or Reply chunk, in one segment.
*/
#define MAX_BYTES_SPECIAL_SEG ((u32)((RPCSVC_MAXPAGES + 2) << PAGE_SHIFT))
/* Sanity check the Read list.
*
* Implementation limits:
* - This implementation supports only one Read chunk.
*
* Sanity checks:
* - Read list does not overflow buffer.
* - Segment size limited by largest NFS data payload.
*
* 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.
*
* Returns pointer to the following Write list.
*/
static __be32 *xdr_check_read_list(__be32 *p, const __be32 *end)
{
u32 position;
bool first;
first = true;
while (*p++ != xdr_zero) {
if (first) {
position = be32_to_cpup(p++);
first = false;
} else if (be32_to_cpup(p++) != position) {
return NULL;
}
p++; /* handle */
if (be32_to_cpup(p++) > MAX_BYTES_SPECIAL_SEG)
return NULL;
p += 2; /* offset */
if (p > end)
return NULL;
}
return p;
}
static __be32 *xdr_check_write_list(__be32 *p, __be32 *end)
{
__be32 *next;
while (*p++ != xdr_zero) {
next = p + 1 + be32_to_cpup(p) * rpcrdma_segment_maxsz;
if (next > end)
return NULL;
p = next;
}
return p;
}
static __be32 *xdr_check_reply_chunk(__be32 *p, __be32 *end)
{
__be32 *next;
if (*p++ != xdr_zero) {
next = p + 1 + be32_to_cpup(p) * rpcrdma_segment_maxsz;
if (next > end)
return NULL;
p = next;
}
return p;
}
/* On entry, xdr->head[0].iov_base points to first byte in the
* RPC-over-RDMA 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)
{
__be32 *p, *end, *rdma_argp;
unsigned int hdr_len;
char *proc;
/* Verify that there's enough bytes for header + something */
if (rq_arg->len <= RPCRDMA_HDRLEN_ERR)
goto out_short;
rdma_argp = rq_arg->head[0].iov_base;
if (*(rdma_argp + 1) != rpcrdma_version)
goto out_version;
switch (*(rdma_argp + 3)) {
case rdma_msg:
proc = "RDMA_MSG";
break;
case rdma_nomsg:
proc = "RDMA_NOMSG";
break;
case rdma_done:
goto out_drop;
case rdma_error:
goto out_drop;
default:
goto out_proc;
}
end = (__be32 *)((unsigned long)rdma_argp + rq_arg->len);
p = xdr_check_read_list(rdma_argp + 4, end);
if (!p)
goto out_inval;
p = xdr_check_write_list(p, end);
if (!p)
goto out_inval;
p = xdr_check_reply_chunk(p, end);
if (!p)
goto out_inval;
if (p > end)
goto out_inval;
rq_arg->head[0].iov_base = p;
hdr_len = (unsigned long)p - (unsigned long)rdma_argp;
rq_arg->head[0].iov_len -= hdr_len;
dprintk("svcrdma: received %s request for XID 0x%08x, hdr_len=%u\n",
proc, be32_to_cpup(rdma_argp), hdr_len);
return hdr_len;
out_short:
dprintk("svcrdma: header too short = %d\n", rq_arg->len);
return -EINVAL;
out_version:
dprintk("svcrdma: bad xprt version: %u\n",
be32_to_cpup(rdma_argp + 1));
return -EPROTONOSUPPORT;
out_drop:
dprintk("svcrdma: dropping RDMA_DONE/ERROR message\n");
return 0;
out_proc:
dprintk("svcrdma: bad rdma procedure (%u)\n",
be32_to_cpup(rdma_argp + 3));
return -EINVAL;
out_inval:
dprintk("svcrdma: failed to parse transport header\n");
return -EINVAL;
}
/* Issue an RDMA_READ using the local lkey to map the data sink */
int rdma_read_chunk_lcl(struct svcxprt_rdma *xprt,
struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *head,
int *page_no,
u32 *page_offset,
u32 rs_handle,
u32 rs_length,
u64 rs_offset,
bool last)
{
struct ib_rdma_wr read_wr;
int pages_needed = PAGE_ALIGN(*page_offset + rs_length) >> PAGE_SHIFT;
struct svc_rdma_op_ctxt *ctxt = svc_rdma_get_context(xprt);
int ret, read, pno;
u32 pg_off = *page_offset;
u32 pg_no = *page_no;
ctxt->direction = DMA_FROM_DEVICE;
ctxt->read_hdr = head;
pages_needed = min_t(int, pages_needed, xprt->sc_max_sge_rd);
read = min_t(int, (pages_needed << PAGE_SHIFT) - *page_offset,
rs_length);
for (pno = 0; pno < pages_needed; pno++) {
int len = min_t(int, rs_length, PAGE_SIZE - pg_off);
head->arg.pages[pg_no] = rqstp->rq_arg.pages[pg_no];
head->arg.page_len += len;
head->arg.len += len;
if (!pg_off)
head->count++;
rqstp->rq_respages = &rqstp->rq_arg.pages[pg_no+1];
rqstp->rq_next_page = rqstp->rq_respages + 1;
ctxt->sge[pno].addr =
ib_dma_map_page(xprt->sc_cm_id->device,
head->arg.pages[pg_no], pg_off,
PAGE_SIZE - pg_off,
DMA_FROM_DEVICE);
ret = ib_dma_mapping_error(xprt->sc_cm_id->device,
ctxt->sge[pno].addr);
if (ret)
goto err;
svc_rdma_count_mappings(xprt, ctxt);
ctxt->sge[pno].lkey = xprt->sc_pd->local_dma_lkey;
ctxt->sge[pno].length = len;
ctxt->count++;
/* adjust offset and wrap to next page if needed */
pg_off += len;
if (pg_off == PAGE_SIZE) {
pg_off = 0;
pg_no++;
}
rs_length -= len;
}
if (last && rs_length == 0)
set_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
else
clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
memset(&read_wr, 0, sizeof(read_wr));
ctxt->cqe.done = svc_rdma_wc_read;
read_wr.wr.wr_cqe = &ctxt->cqe;
read_wr.wr.opcode = IB_WR_RDMA_READ;
read_wr.wr.send_flags = IB_SEND_SIGNALED;
read_wr.rkey = rs_handle;
read_wr.remote_addr = rs_offset;
read_wr.wr.sg_list = ctxt->sge;
read_wr.wr.num_sge = pages_needed;
ret = svc_rdma_send(xprt, &read_wr.wr);
if (ret) {
pr_err("svcrdma: Error %d posting RDMA_READ\n", ret);
set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
goto err;
}
/* return current location in page array */
*page_no = pg_no;
*page_offset = pg_off;
ret = read;
atomic_inc(&rdma_stat_read);
return ret;
err:
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 0);
return ret;
}
/* Issue an RDMA_READ using an FRMR to map the data sink */
int rdma_read_chunk_frmr(struct svcxprt_rdma *xprt,
struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *head,
int *page_no,
u32 *page_offset,
u32 rs_handle,
u32 rs_length,
u64 rs_offset,
bool last)
{
struct ib_rdma_wr read_wr;
struct ib_send_wr inv_wr;
struct ib_reg_wr reg_wr;
u8 key;
int nents = PAGE_ALIGN(*page_offset + rs_length) >> PAGE_SHIFT;
struct svc_rdma_op_ctxt *ctxt = svc_rdma_get_context(xprt);
struct svc_rdma_fastreg_mr *frmr = svc_rdma_get_frmr(xprt);
int ret, read, pno, dma_nents, n;
u32 pg_off = *page_offset;
u32 pg_no = *page_no;
if (IS_ERR(frmr))
return -ENOMEM;
ctxt->direction = DMA_FROM_DEVICE;
ctxt->frmr = frmr;
nents = min_t(unsigned int, nents, xprt->sc_frmr_pg_list_len);
read = min_t(int, (nents << PAGE_SHIFT) - *page_offset, rs_length);
frmr->direction = DMA_FROM_DEVICE;
frmr->access_flags = (IB_ACCESS_LOCAL_WRITE|IB_ACCESS_REMOTE_WRITE);
frmr->sg_nents = nents;
for (pno = 0; pno < nents; pno++) {
int len = min_t(int, rs_length, PAGE_SIZE - pg_off);
head->arg.pages[pg_no] = rqstp->rq_arg.pages[pg_no];
head->arg.page_len += len;
head->arg.len += len;
if (!pg_off)
head->count++;
sg_set_page(&frmr->sg[pno], rqstp->rq_arg.pages[pg_no],
len, pg_off);
rqstp->rq_respages = &rqstp->rq_arg.pages[pg_no+1];
rqstp->rq_next_page = rqstp->rq_respages + 1;
/* adjust offset and wrap to next page if needed */
pg_off += len;
if (pg_off == PAGE_SIZE) {
pg_off = 0;
pg_no++;
}
rs_length -= len;
}
if (last && rs_length == 0)
set_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
else
clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
dma_nents = ib_dma_map_sg(xprt->sc_cm_id->device,
frmr->sg, frmr->sg_nents,
frmr->direction);
if (!dma_nents) {
pr_err("svcrdma: failed to dma map sg %p\n",
frmr->sg);
return -ENOMEM;
}
n = ib_map_mr_sg(frmr->mr, frmr->sg, frmr->sg_nents, NULL, PAGE_SIZE);
if (unlikely(n != frmr->sg_nents)) {
pr_err("svcrdma: failed to map mr %p (%d/%d elements)\n",
frmr->mr, n, frmr->sg_nents);
return n < 0 ? n : -EINVAL;
}
/* Bump the key */
key = (u8)(frmr->mr->lkey & 0x000000FF);
ib_update_fast_reg_key(frmr->mr, ++key);
ctxt->sge[0].addr = frmr->mr->iova;
ctxt->sge[0].lkey = frmr->mr->lkey;
ctxt->sge[0].length = frmr->mr->length;
ctxt->count = 1;
ctxt->read_hdr = head;
/* Prepare REG WR */
ctxt->reg_cqe.done = svc_rdma_wc_reg;
reg_wr.wr.wr_cqe = &ctxt->reg_cqe;
reg_wr.wr.opcode = IB_WR_REG_MR;
reg_wr.wr.send_flags = IB_SEND_SIGNALED;
reg_wr.wr.num_sge = 0;
reg_wr.mr = frmr->mr;
reg_wr.key = frmr->mr->lkey;
reg_wr.access = frmr->access_flags;
reg_wr.wr.next = &read_wr.wr;
/* Prepare RDMA_READ */
memset(&read_wr, 0, sizeof(read_wr));
ctxt->cqe.done = svc_rdma_wc_read;
read_wr.wr.wr_cqe = &ctxt->cqe;
read_wr.wr.send_flags = IB_SEND_SIGNALED;
read_wr.rkey = rs_handle;
read_wr.remote_addr = rs_offset;
read_wr.wr.sg_list = ctxt->sge;
read_wr.wr.num_sge = 1;
if (xprt->sc_dev_caps & SVCRDMA_DEVCAP_READ_W_INV) {
read_wr.wr.opcode = IB_WR_RDMA_READ_WITH_INV;
read_wr.wr.ex.invalidate_rkey = ctxt->frmr->mr->lkey;
} else {
read_wr.wr.opcode = IB_WR_RDMA_READ;
read_wr.wr.next = &inv_wr;
/* Prepare invalidate */
memset(&inv_wr, 0, sizeof(inv_wr));
ctxt->inv_cqe.done = svc_rdma_wc_inv;
inv_wr.wr_cqe = &ctxt->inv_cqe;
inv_wr.opcode = IB_WR_LOCAL_INV;
inv_wr.send_flags = IB_SEND_SIGNALED | IB_SEND_FENCE;
inv_wr.ex.invalidate_rkey = frmr->mr->lkey;
}
/* Post the chain */
ret = svc_rdma_send(xprt, &reg_wr.wr);
if (ret) {
pr_err("svcrdma: Error %d posting RDMA_READ\n", ret);
set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
goto err;
}
/* return current location in page array */
*page_no = pg_no;
*page_offset = pg_off;
ret = read;
atomic_inc(&rdma_stat_read);
return ret;
err:
svc_rdma_put_context(ctxt, 0);
svc_rdma_put_frmr(xprt, frmr);
return ret;
}
/* If there was additional inline content, append it to the end of arg.pages.
* Tail copy has to be done after the reader function has determined how many
* pages are needed for RDMA READ.
*/
static int
rdma_copy_tail(struct svc_rqst *rqstp, struct svc_rdma_op_ctxt *head,
u32 position, u32 byte_count, u32 page_offset, int page_no)
{
char *srcp, *destp;
srcp = head->arg.head[0].iov_base + position;
byte_count = head->arg.head[0].iov_len - position;
if (byte_count > PAGE_SIZE) {
dprintk("svcrdma: large tail unsupported\n");
return 0;
}
/* Fit as much of the tail on the current page as possible */
if (page_offset != PAGE_SIZE) {
destp = page_address(rqstp->rq_arg.pages[page_no]);
destp += page_offset;
while (byte_count--) {
*destp++ = *srcp++;
page_offset++;
if (page_offset == PAGE_SIZE && byte_count)
goto more;
}
goto done;
}
more:
/* Fit the rest on the next page */
page_no++;
destp = page_address(rqstp->rq_arg.pages[page_no]);
while (byte_count--)
*destp++ = *srcp++;
rqstp->rq_respages = &rqstp->rq_arg.pages[page_no+1];
rqstp->rq_next_page = rqstp->rq_respages + 1;
done:
byte_count = head->arg.head[0].iov_len - position;
head->arg.page_len += byte_count;
head->arg.len += byte_count;
head->arg.buflen += byte_count;
return 1;
}
/* Returns the address of the first read chunk or <nul> if no read chunk
* is present
*/
static struct rpcrdma_read_chunk *
svc_rdma_get_read_chunk(struct rpcrdma_msg *rmsgp)
{
struct rpcrdma_read_chunk *ch =
(struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
if (ch->rc_discrim == xdr_zero)
return NULL;
return ch;
}
static int rdma_read_chunks(struct svcxprt_rdma *xprt,
struct rpcrdma_msg *rmsgp,
struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *head)
{
int page_no, ret;
struct rpcrdma_read_chunk *ch;
u32 handle, page_offset, byte_count;
u32 position;
u64 rs_offset;
bool last;
/* If no read list is present, return 0 */
ch = svc_rdma_get_read_chunk(rmsgp);
if (!ch)
return 0;
/* The request is completed when the RDMA_READs complete. The
* head context keeps all the pages that comprise the
* request.
*/
head->arg.head[0] = rqstp->rq_arg.head[0];
head->arg.tail[0] = rqstp->rq_arg.tail[0];
head->hdr_count = head->count;
head->arg.page_base = 0;
head->arg.page_len = 0;
head->arg.len = rqstp->rq_arg.len;
head->arg.buflen = rqstp->rq_arg.buflen;
/* RDMA_NOMSG: RDMA READ data should land just after RDMA RECV data */
position = be32_to_cpu(ch->rc_position);
if (position == 0) {
head->arg.pages = &head->pages[0];
page_offset = head->byte_len;
} else {
head->arg.pages = &head->pages[head->count];
page_offset = 0;
}
ret = 0;
page_no = 0;
for (; ch->rc_discrim != xdr_zero; ch++) {
if (be32_to_cpu(ch->rc_position) != position)
goto err;
handle = be32_to_cpu(ch->rc_target.rs_handle),
byte_count = be32_to_cpu(ch->rc_target.rs_length);
xdr_decode_hyper((__be32 *)&ch->rc_target.rs_offset,
&rs_offset);
while (byte_count > 0) {
last = (ch + 1)->rc_discrim == xdr_zero;
ret = xprt->sc_reader(xprt, rqstp, head,
&page_no, &page_offset,
handle, byte_count,
rs_offset, last);
if (ret < 0)
goto err;
byte_count -= ret;
rs_offset += ret;
head->arg.buflen += ret;
}
}
/* Read list may need XDR round-up (see RFC 5666, s. 3.7) */
if (page_offset & 3) {
u32 pad = 4 - (page_offset & 3);
head->arg.tail[0].iov_len += pad;
head->arg.len += pad;
head->arg.buflen += pad;
page_offset += pad;
}
ret = 1;
if (position && position < head->arg.head[0].iov_len)
ret = rdma_copy_tail(rqstp, head, position,
byte_count, page_offset, page_no);
head->arg.head[0].iov_len = position;
head->position = position;
err:
/* Detach arg pages. svc_recv will replenish them */
for (page_no = 0;
&rqstp->rq_pages[page_no] < rqstp->rq_respages; page_no++)
rqstp->rq_pages[page_no] = NULL;
return ret;
}
static void rdma_read_complete(struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *head)
{
int page_no;
/* Copy RPC pages */
for (page_no = 0; page_no < head->count; page_no++) {
put_page(rqstp->rq_pages[page_no]);
rqstp->rq_pages[page_no] = head->pages[page_no];
}
/* Adjustments made for RDMA_NOMSG type requests */
if (head->position == 0) {
if (head->arg.len <= head->sge[0].length) {
head->arg.head[0].iov_len = head->arg.len -
head->byte_len;
head->arg.page_len = 0;
} else {
head->arg.head[0].iov_len = head->sge[0].length -
head->byte_len;
head->arg.page_len = head->arg.len -
head->sge[0].length;
}
}
/* Point rq_arg.pages past header */
rqstp->rq_arg.pages = &rqstp->rq_pages[head->hdr_count];
rqstp->rq_arg.page_len = head->arg.page_len;
rqstp->rq_arg.page_base = head->arg.page_base;
/* rq_respages starts after the last arg page */
rqstp->rq_respages = &rqstp->rq_pages[page_no];
rqstp->rq_next_page = rqstp->rq_respages + 1;
/* Rebuild rq_arg head and tail. */
rqstp->rq_arg.head[0] = head->arg.head[0];
rqstp->rq_arg.tail[0] = head->arg.tail[0];
rqstp->rq_arg.len = head->arg.len;
rqstp->rq_arg.buflen = head->arg.buflen;
}
static void svc_rdma_send_error(struct svcxprt_rdma *xprt,
__be32 *rdma_argp, int status)
{
struct svc_rdma_op_ctxt *ctxt;
__be32 *p, *err_msgp;
unsigned int length;
struct page *page;
int ret;
ret = svc_rdma_repost_recv(xprt, GFP_KERNEL);
if (ret)
return;
page = alloc_page(GFP_KERNEL);
if (!page)
return;
err_msgp = page_address(page);
p = err_msgp;
*p++ = *rdma_argp;
*p++ = *(rdma_argp + 1);
*p++ = xprt->sc_fc_credits;
*p++ = rdma_error;
if (status == -EPROTONOSUPPORT) {
*p++ = err_vers;
*p++ = rpcrdma_version;
*p++ = rpcrdma_version;
} else {
*p++ = err_chunk;
}
length = (unsigned long)p - (unsigned long)err_msgp;
/* Map transport header; no RPC message payload */
ctxt = svc_rdma_get_context(xprt);
ret = svc_rdma_map_reply_hdr(xprt, ctxt, err_msgp, length);
if (ret) {
dprintk("svcrdma: Error %d mapping send for protocol error\n",
ret);
return;
}
ret = svc_rdma_post_send_wr(xprt, ctxt, 1, 0);
if (ret) {
dprintk("svcrdma: Error %d posting send for protocol error\n",
ret);
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 1);
}
}
/* 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_backchannel_reply(struct svc_xprt *xprt,
__be32 *rdma_resp)
{
__be32 *p;
if (!xprt->xpt_bc_xprt)
return false;
p = rdma_resp + 3;
if (*p++ != rdma_msg)
return false;
if (*p++ != xdr_zero)
return false;
if (*p++ != xdr_zero)
return false;
if (*p++ != xdr_zero)
return false;
/* XID sanity */
if (*p++ != *rdma_resp)
return false;
/* call direction */
if (*p == cpu_to_be32(RPC_CALL))
return false;
return true;
}
/*
* Set up the rqstp thread context to point to the RQ buffer. If
* necessary, pull additional data from the client with an RDMA_READ
* request.
*/
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_op_ctxt *ctxt = NULL;
struct rpcrdma_msg *rmsgp;
int ret = 0;
dprintk("svcrdma: rqstp=%p\n", rqstp);
spin_lock(&rdma_xprt->sc_rq_dto_lock);
if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
ctxt = list_first_entry(&rdma_xprt->sc_read_complete_q,
struct svc_rdma_op_ctxt, list);
list_del(&ctxt->list);
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
rdma_read_complete(rqstp, ctxt);
goto complete;
} else if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
ctxt = list_first_entry(&rdma_xprt->sc_rq_dto_q,
struct svc_rdma_op_ctxt, list);
list_del(&ctxt->list);
} else {
atomic_inc(&rdma_stat_rq_starve);
clear_bit(XPT_DATA, &xprt->xpt_flags);
ctxt = NULL;
}
spin_unlock(&rdma_xprt->sc_rq_dto_lock);
if (!ctxt) {
/* This is the EAGAIN path. The svc_recv routine will
* return -EAGAIN, the nfsd thread will go to call into
* svc_recv again and we shouldn't be on the active
* transport list
*/
if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
goto defer;
goto out;
}
dprintk("svcrdma: processing ctxt=%p on xprt=%p, rqstp=%p\n",
ctxt, rdma_xprt, rqstp);
atomic_inc(&rdma_stat_recv);
/* Build up the XDR from the receive buffers. */
rdma_build_arg_xdr(rqstp, ctxt, ctxt->byte_len);
/* Decode the RDMA header. */
rmsgp = (struct rpcrdma_msg *)rqstp->rq_arg.head[0].iov_base;
ret = svc_rdma_xdr_decode_req(&rqstp->rq_arg);
if (ret < 0)
goto out_err;
if (ret == 0)
goto out_drop;
rqstp->rq_xprt_hlen = ret;
if (svc_rdma_is_backchannel_reply(xprt, &rmsgp->rm_xid)) {
ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt,
&rmsgp->rm_xid,
&rqstp->rq_arg);
svc_rdma_put_context(ctxt, 0);
if (ret)
goto repost;
return ret;
}
/* Read read-list data. */
ret = rdma_read_chunks(rdma_xprt, rmsgp, rqstp, ctxt);
if (ret > 0) {
/* read-list posted, defer until data received from client. */
goto defer;
} else if (ret < 0) {
/* Post of read-list failed, free context. */
svc_rdma_put_context(ctxt, 1);
return 0;
}
complete:
ret = rqstp->rq_arg.head[0].iov_len
+ rqstp->rq_arg.page_len
+ rqstp->rq_arg.tail[0].iov_len;
svc_rdma_put_context(ctxt, 0);
out:
dprintk("svcrdma: ret=%d, rq_arg.len=%u, "
"rq_arg.head[0].iov_base=%p, rq_arg.head[0].iov_len=%zd\n",
ret, rqstp->rq_arg.len,
rqstp->rq_arg.head[0].iov_base,
rqstp->rq_arg.head[0].iov_len);
rqstp->rq_prot = IPPROTO_MAX;
svc_xprt_copy_addrs(rqstp, xprt);
return ret;
out_err:
svc_rdma_send_error(rdma_xprt, &rmsgp->rm_xid, ret);
svc_rdma_put_context(ctxt, 0);
return 0;
defer:
return 0;
out_drop:
svc_rdma_put_context(ctxt, 1);
repost:
return svc_rdma_repost_recv(rdma_xprt, GFP_KERNEL);
}
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