/*
* 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;
struct ib_send_wr inv_wr;
int err = 0;
int ch_no;
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_req_map *rpl_map;
struct svc_rdma_req_map *chl_map;
/* If no read list is present, return 0 */
ch = svc_rdma_get_read_chunk(rmsgp);
if (!ch)
return 0;
svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
if (ch_count > RPCSVC_MAXPAGES)
return -EINVAL;
/* Allocate temporary reply and chunk maps */
rpl_map = svc_rdma_get_req_map();
chl_map = svc_rdma_get_req_map();
if (!xprt->sc_frmr_pg_list_len)
sge_count = map_read_chunks(xprt, rqstp, hdr_ctxt, rmsgp,
rpl_map, chl_map, ch_count,
byte_count);
else
sge_count = fast_reg_read_chunks(xprt, rqstp, hdr_ctxt, rmsgp,
rpl_map, chl_map, ch_count,
byte_count);
if (sge_count < 0) {
err = -EIO;
goto out;
}
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;
ctxt->frmr = hdr_ctxt->frmr;
ctxt->read_hdr = NULL;
clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
/* Prepare READ WR */
memset(&read_wr, 0, sizeof read_wr);
read_wr.wr_id = (unsigned long)ctxt;
read_wr.opcode = IB_WR_RDMA_READ;
ctxt->wr_op = read_wr.opcode;
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 = ctxt->sge;
read_wr.num_sge =
rdma_read_max_sge(xprt, chl_map->ch[ch_no].count);
err = rdma_set_ctxt_sge(xprt, ctxt, hdr_ctxt->frmr,
&rpl_map->sge[chl_map->ch[ch_no].start],
&sgl_offset,
read_wr.num_sge);
if (err) {
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 0);
goto out;
}
if (((ch+1)->rc_discrim == 0) &&
(read_wr.num_sge == chl_map->ch[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);
if (hdr_ctxt->frmr) {
set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
/*
* Invalidate the local MR used to map the data
* sink.
*/
if (xprt->sc_dev_caps &
SVCRDMA_DEVCAP_READ_W_INV) {
read_wr.opcode =
IB_WR_RDMA_READ_WITH_INV;
ctxt->wr_op = read_wr.opcode;
read_wr.ex.invalidate_rkey =
ctxt->frmr->mr->lkey;
} else {
/* Prepare INVALIDATE WR */
memset(&inv_wr, 0, sizeof inv_wr);
inv_wr.opcode = IB_WR_LOCAL_INV;
inv_wr.send_flags = IB_SEND_SIGNALED;
inv_wr.ex.invalidate_rkey =
hdr_ctxt->frmr->mr->lkey;
read_wr.next = &inv_wr;
}
}
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_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 0);
goto out;
}
atomic_inc(&rdma_stat_read);
if (read_wr.num_sge < chl_map->ch[ch_no].count) {
chl_map->ch[ch_no].count -= read_wr.num_sge;
chl_map->ch[ch_no].start += read_wr.num_sge;
goto next_sge;
}
sgl_offset = 0;
err = 1;
}
out:
svc_rdma_put_req_map(rpl_map);
svc_rdma_put_req_map(chl_map);
/* 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_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;
struct ib_send_wr inv_wr;
int err = 0;
int ch_no;
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_req_map *rpl_map;
struct svc_rdma_req_map *chl_map;
/* */
ch = svc_rdma_get_read_chunk(rmsgp);
if (!ch)
return 0;
svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
if (ch_count > RPCSVC_MAXPAGES)
return -EINVAL;
/* */
rpl_map = svc_rdma_get_req_map();
chl_map = svc_rdma_get_req_map();
if (!xprt->sc_frmr_pg_list_len)
sge_count = map_read_chunks(xprt, rqstp, hdr_ctxt, rmsgp,
rpl_map, chl_map, ch_count,
byte_count);
else
sge_count = fast_reg_read_chunks(xprt, rqstp, hdr_ctxt, rmsgp,
rpl_map, chl_map, ch_count,
byte_count);
if (sge_count < 0) {
err = -EIO;
goto out;
}
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++) {
u64 rs_offset;
next_sge:
ctxt = svc_rdma_get_context(xprt);
ctxt->direction = DMA_FROM_DEVICE;
ctxt->frmr = hdr_ctxt->frmr;
ctxt->read_hdr = NULL;
clear_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
clear_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
/* */
memset(&read_wr, 0, sizeof read_wr);
read_wr.wr_id = (unsigned long)ctxt;
read_wr.opcode = IB_WR_RDMA_READ;
ctxt->wr_op = read_wr.opcode;
read_wr.send_flags = IB_SEND_SIGNALED;
read_wr.wr.rdma.rkey = ntohl(ch->rc_target.rs_handle);
xdr_decode_hyper((__be32 *)&ch->rc_target.rs_offset,
&rs_offset);
read_wr.wr.rdma.remote_addr = rs_offset + sgl_offset;
read_wr.sg_list = ctxt->sge;
read_wr.num_sge =
rdma_read_max_sge(xprt, chl_map->ch[ch_no].count);
err = rdma_set_ctxt_sge(xprt, ctxt, hdr_ctxt->frmr,
&rpl_map->sge[chl_map->ch[ch_no].start],
&sgl_offset,
read_wr.num_sge);
if (err) {
svc_rdma_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 0);
goto out;
}
if (((ch+1)->rc_discrim == 0) &&
(read_wr.num_sge == chl_map->ch[ch_no].count)) {
/*
*/
set_bit(RDMACTXT_F_LAST_CTXT, &ctxt->flags);
if (hdr_ctxt->frmr) {
set_bit(RDMACTXT_F_FAST_UNREG, &ctxt->flags);
/*
*/
if (xprt->sc_dev_caps &
SVCRDMA_DEVCAP_READ_W_INV) {
read_wr.opcode =
IB_WR_RDMA_READ_WITH_INV;
ctxt->wr_op = read_wr.opcode;
read_wr.ex.invalidate_rkey =
ctxt->frmr->mr->lkey;
} else {
/* */
memset(&inv_wr, 0, sizeof inv_wr);
inv_wr.opcode = IB_WR_LOCAL_INV;
inv_wr.send_flags = IB_SEND_SIGNALED;
inv_wr.ex.invalidate_rkey =
hdr_ctxt->frmr->mr->lkey;
read_wr.next = &inv_wr;
}
}
ctxt->read_hdr = hdr_ctxt;
}
/* */
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_unmap_dma(ctxt);
svc_rdma_put_context(ctxt, 0);
goto out;
}
atomic_inc(&rdma_stat_read);
if (read_wr.num_sge < chl_map->ch[ch_no].count) {
chl_map->ch[ch_no].count -= read_wr.num_sge;
chl_map->ch[ch_no].start += read_wr.num_sge;
goto next_sge;
}
sgl_offset = 0;
err = 1;
}
out:
svc_rdma_put_req_map(rpl_map);
svc_rdma_put_req_map(chl_map);
/* */
for (ch_no = 0; &rqstp->rq_pages[ch_no] < rqstp->rq_respages; ch_no++)
rqstp->rq_pages[ch_no] = NULL;
/*
*/
while (rqstp->rq_resused)
rqstp->rq_respages[--rqstp->rq_resused] = NULL;
return err;
}
