/*
* 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/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 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(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;
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(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];
/* We should never run out of SGE because the limit is defined to
* support the max allowed RPC data length
*/
BUG_ON(bc && (sge_no == ctxt->count));
BUG_ON((rqstp->rq_arg.head[0].iov_len + rqstp->rq_arg.page_len)
!= byte_count);
BUG_ON(rqstp->rq_arg.len != byte_count);
/* 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;
}
struct chunk_sge {
int start; /* sge no for this chunk */
int count; /* sge count for this chunk */
};
/* Encode a read-chunk-list as an array of IB SGE
*
* Assumptions:
* - chunk[0]->position points to pages[0] at an offset of 0
* - pages[] is not physically or virtually contigous and consists of
* PAGE_SIZE elements.
*
* Output:
* - sge array pointing into pages[] array.
* - chunk_sge array specifying sge index and count for each
* chunk in the read list
*
*/
static int rdma_rcl_to_sge(struct svcxprt_rdma *xprt,
struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *head,
struct rpcrdma_msg *rmsgp,
struct ib_sge *sge,
struct chunk_sge *ch_sge_ary,
int ch_count,
int byte_count)
{
int sge_no;
int sge_bytes;
int page_off;
int page_no;
int ch_bytes;
int ch_no;
struct rpcrdma_read_chunk *ch;
sge_no = 0;
page_no = 0;
page_off = 0;
ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
ch_no = 0;
ch_bytes = ch->rc_target.rs_length;
head->arg.head[0] = rqstp->rq_arg.head[0];
head->arg.tail[0] = rqstp->rq_arg.tail[0];
head->arg.pages = &head->pages[head->count];
head->sge[0].length = head->count; /* save count of hdr pages */
head->arg.page_base = 0;
head->arg.page_len = ch_bytes;
head->arg.len = rqstp->rq_arg.len + ch_bytes;
head->arg.buflen = rqstp->rq_arg.buflen + ch_bytes;
head->count++;
ch_sge_ary[0].start = 0;
while (byte_count) {
sge_bytes = min_t(int, PAGE_SIZE-page_off, ch_bytes);
sge[sge_no].addr =
ib_dma_map_page(xprt->sc_cm_id->device,
rqstp->rq_arg.pages[page_no],
page_off, sge_bytes,
DMA_FROM_DEVICE);
sge[sge_no].length = sge_bytes;
sge[sge_no].lkey = xprt->sc_phys_mr->lkey;
/*
* Don't bump head->count here because the same page
* may be used by multiple SGE.
*/
head->arg.pages[page_no] = rqstp->rq_arg.pages[page_no];
rqstp->rq_respages = &rqstp->rq_arg.pages[page_no+1];
byte_count -= sge_bytes;
ch_bytes -= sge_bytes;
sge_no++;
/*
* If all bytes for this chunk have been mapped to an
* SGE, move to the next SGE
*/
if (ch_bytes == 0) {
ch_sge_ary[ch_no].count =
sge_no - ch_sge_ary[ch_no].start;
ch_no++;
ch++;
ch_sge_ary[ch_no].start = sge_no;
ch_bytes = ch->rc_target.rs_length;
/* If bytes remaining account for next chunk */
if (byte_count) {
head->arg.page_len += ch_bytes;
head->arg.len += ch_bytes;
head->arg.buflen += ch_bytes;
}
}
/*
* If this SGE consumed all of the page, move to the
* next page
*/
if ((sge_bytes + page_off) == PAGE_SIZE) {
page_no++;
page_off = 0;
/*
* If there are still bytes left to map, bump
* the page count
*/
if (byte_count)
head->count++;
} else
page_off += sge_bytes;
}
BUG_ON(byte_count != 0);
return sge_no;
}
static void rdma_set_ctxt_sge(struct svc_rdma_op_ctxt *ctxt,
struct ib_sge *sge,
u64 *sgl_offset,
int count)
{
int i;
ctxt->count = count;
for (i = 0; i < count; i++) {
ctxt->sge[i].addr = sge[i].addr;
ctxt->sge[i].length = sge[i].length;
*sgl_offset = *sgl_offset + sge[i].length;
}
}
static int rdma_read_max_sge(struct svcxprt_rdma *xprt, int sge_count)
{
if ((RDMA_TRANSPORT_IWARP ==
rdma_node_get_transport(xprt->sc_cm_id->
device->node_type))
&& sge_count > 1)
return 1;
else
return min_t(int, sge_count, xprt->sc_max_sge);
}
/*
* Use RDMA_READ to read data from the advertised client buffer into the
* XDR stream starting at rq_arg.head[0].iov_base.
* Each chunk in the array
* contains the following fields:
* discrim - '1', This isn't used for data placement
* position - The xdr stream offset (the same for every chunk)
* handle - RMR for client memory region
* length - data transfer length
* offset - 64 bit tagged offset in remote memory region
*
* On our side, we need to read into a pagelist. The first page immediately
* follows the RPC header.
*
* This function returns:
* 0 - No error and no read-list found.
*
* 1 - Successful read-list processing. The data is not yet in
* the pagelist and therefore the RPC request must be deferred. The
* I/O completion will enqueue the transport again and
* svc_rdma_recvfrom will complete the request.
*
* <0 - Error processing/posting read-list.
*
* NOTE: The ctxt must not be touched after the last WR has been posted
* because the I/O completion processing may occur on another
* processor and free / modify the context. Ne touche pas!
*/
static int rdma_read_xdr(struct svcxprt_rdma *xprt,
struct rpcrdma_msg *rmsgp,
struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *hdr_ctxt)
{
struct ib_send_wr read_wr;
int err = 0;
int ch_no;
struct ib_sge *sge;
int ch_count;
int byte_count;
int sge_count;
u64 sgl_offset;
struct rpcrdma_read_chunk *ch;
struct svc_rdma_op_ctxt *ctxt = NULL;
struct svc_rdma_op_ctxt *tmp_sge_ctxt;
struct svc_rdma_op_ctxt *tmp_ch_ctxt;
struct chunk_sge *ch_sge_ary;
/* If no read list is present, return 0 */
ch = svc_rdma_get_read_chunk(rmsgp);
if (!ch)
return 0;
/* Allocate temporary contexts to keep SGE */
BUG_ON(sizeof(struct ib_sge) < sizeof(struct chunk_sge));
tmp_sge_ctxt = svc_rdma_get_context(xprt);
sge = tmp_sge_ctxt->sge;
tmp_ch_ctxt = svc_rdma_get_context(xprt);
ch_sge_ary = (struct chunk_sge *)tmp_ch_ctxt->sge;
svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
sge_count = rdma_rcl_to_sge(xprt, rqstp, hdr_ctxt, rmsgp,
sge, ch_sge_ary,
ch_count, byte_count);
sgl_offset = 0;
ch_no = 0;
for (ch = (struct rpcrdma_read_chunk *)&rmsgp->rm_body.rm_chunks[0];
ch->rc_discrim != 0; ch++, ch_no++) {
next_sge:
ctxt = svc_rdma_get_context(xprt);
ctxt->direction = DMA_FROM_DEVICE;
clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
/* Prepare READ WR */
memset(&read_wr, 0, sizeof read_wr);
ctxt->wr_op = IB_WR_RDMA_READ;
read_wr.wr_id = (unsigned long)ctxt;
read_wr.opcode = IB_WR_RDMA_READ;
read_wr.send_flags = IB_SEND_SIGNALED;
read_wr.wr.rdma.rkey = ch->rc_target.rs_handle;
read_wr.wr.rdma.remote_addr =
get_unaligned(&(ch->rc_target.rs_offset)) +
sgl_offset;
read_wr.sg_list = &sge[ch_sge_ary[ch_no].start];
read_wr.num_sge =
rdma_read_max_sge(xprt, ch_sge_ary[ch_no].count);
rdma_set_ctxt_sge(ctxt, &sge[ch_sge_ary[ch_no].start],
&sgl_offset,
read_wr.num_sge);
if (((ch+1)->rc_discrim == 0) &&
(read_wr.num_sge == ch_sge_ary[ch_no].count)) {
/*
* Mark the last RDMA_READ with a bit to
* indicate all RPC data has been fetched from
* the client and the RPC needs to be enqueued.
*/
set_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
ctxt->read_hdr = hdr_ctxt;
}
/* Post the read */
err = svc_rdma_send(xprt, &read_wr);
if (err) {
printk(KERN_ERR "svcrdma: Error %d posting RDMA_READ\n",
err);
set_bit(XPT_CLOSE, &xprt->sc_xprt.xpt_flags);
svc_rdma_put_context(ctxt, 0);
goto out;
}
atomic_inc(&rdma_stat_read);
if (read_wr.num_sge < ch_sge_ary[ch_no].count) {
ch_sge_ary[ch_no].count -= read_wr.num_sge;
ch_sge_ary[ch_no].start += read_wr.num_sge;
goto next_sge;
}
sgl_offset = 0;
err = 1;
}
out:
svc_rdma_put_context(tmp_sge_ctxt, 0);
svc_rdma_put_context(tmp_ch_ctxt, 0);
/* Detach arg pages. svc_recv will replenish them */
for (ch_no = 0; &rqstp->rq_pages[ch_no] < rqstp->rq_respages; ch_no++)
rqstp->rq_pages[ch_no] = NULL;
/*
* Detach res pages. svc_release must see a resused count of
* zero or it will attempt to put them.
*/
while (rqstp->rq_resused)
rqstp->rq_respages[--rqstp->rq_resused] = NULL;
return err;
}
static int rdma_read_complete(struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *head)
{
int page_no;
int ret;
BUG_ON(!head);
/* 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];
}
/* Point rq_arg.pages past header */
rqstp->rq_arg.pages = &rqstp->rq_pages[head->sge[0].length];
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_arg.pages[page_no];
rqstp->rq_resused = 0;
/* 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;
/* Free the context */
svc_rdma_put_context(head, 0);
/* XXX: What should this be? */
rqstp->rq_prot = IPPROTO_MAX;
ret = rqstp->rq_arg.head[0].iov_len
+ rqstp->rq_arg.page_len
+ rqstp->rq_arg.tail[0].iov_len;
dprintk("svcrdma: deferred read ret=%d, rq_arg.len =%d, "
"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);
svc_xprt_received(rqstp->rq_xprt);
return ret;
}
/*
* 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;
int len;
dprintk("svcrdma: rqstp=%p\n", rqstp);
spin_lock_bh(&rdma_xprt->sc_read_complete_lock);
if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
ctxt = list_entry(rdma_xprt->sc_read_complete_q.next,
struct svc_rdma_op_ctxt,
dto_q);
list_del_init(&ctxt->dto_q);
}
spin_unlock_bh(&rdma_xprt->sc_read_complete_lock);
if (ctxt)
return rdma_read_complete(rqstp, ctxt);
spin_lock_bh(&rdma_xprt->sc_rq_dto_lock);
if (!list_empty(&rdma_xprt->sc_rq_dto_q)) {
ctxt = list_entry(rdma_xprt->sc_rq_dto_q.next,
struct svc_rdma_op_ctxt,
dto_q);
list_del_init(&ctxt->dto_q);
} else {
atomic_inc(&rdma_stat_rq_starve);
clear_bit(XPT_DATA, &xprt->xpt_flags);
ctxt = NULL;
}
spin_unlock_bh(&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 close_out;
BUG_ON(ret);
goto out;
}
dprintk("svcrdma: processing ctxt=%p on xprt=%p, rqstp=%p, status=%d\n",
ctxt, rdma_xprt, rqstp, ctxt->wc_status);
BUG_ON(ctxt->wc_status != IB_WC_SUCCESS);
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. */
len = svc_rdma_xdr_decode_req(&rmsgp, rqstp);
rqstp->rq_xprt_hlen = len;
/* If the request is invalid, reply with an error */
if (len < 0) {
if (len == -ENOSYS)
(void)svc_rdma_send_error(rdma_xprt, rmsgp, ERR_VERS);
goto close_out;
}
/* Read read-list data. */
ret = rdma_read_xdr(rdma_xprt, rmsgp, rqstp, ctxt);
if (ret > 0) {
/* read-list posted, defer until data received from client. */
svc_xprt_received(xprt);
return 0;
}
if (ret < 0) {
/* Post of read-list failed, free context. */
svc_rdma_put_context(ctxt, 1);
return 0;
}
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 =%d, "
"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);
svc_xprt_received(xprt);
return ret;
close_out:
if (ctxt)
svc_rdma_put_context(ctxt, 1);
dprintk("svcrdma: transport %p is closing\n", xprt);
/*
* Set the close bit and enqueue it. svc_recv will see the
* close bit and call svc_xprt_delete
*/
set_bit(XPT_CLOSE, &xprt->xpt_flags);
svc_xprt_received(xprt);
return 0;
}
