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/*
* Copyright (c) 2015 Oracle. All rights reserved.
* Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
*/
/* No-op chunk preparation. All client memory is pre-registered.
* Sometimes referred to as ALLPHYSICAL mode.
*
* Physical registration is simple because all client memory is
* pre-registered and never deregistered. This mode is good for
* adapter bring up, but is considered not safe: the server is
* trusted not to abuse its access to client memory not involved
* in RDMA I/O.
*/
#include "xprt_rdma.h"
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_TRANS
#endif
static int
physical_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
struct rpcrdma_create_data_internal *cdata)
{
struct ib_mr *mr;
/* Obtain an rkey to use for RPC data payloads.
*/
mr = ib_get_dma_mr(ia->ri_pd,
IB_ACCESS_LOCAL_WRITE |
IB_ACCESS_REMOTE_WRITE |
IB_ACCESS_REMOTE_READ);
if (IS_ERR(mr)) {
pr_err("%s: ib_get_dma_mr for failed with %lX\n",
__func__, PTR_ERR(mr));
return -ENOMEM;
}
ia->ri_dma_mr = mr;
rpcrdma_set_max_header_sizes(ia, cdata, min_t(unsigned int,
RPCRDMA_MAX_DATA_SEGS,
RPCRDMA_MAX_HDR_SEGS));
return 0;
}
/* PHYSICAL memory registration conveys one page per chunk segment.
*/
static size_t
physical_op_maxpages(struct rpcrdma_xprt *r_xprt)
{
return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
RPCRDMA_MAX_HDR_SEGS);
}
static int
physical_op_init(struct rpcrdma_xprt *r_xprt)
{
return 0;
}
/* The client's physical memory is already exposed for
* remote access via RDMA READ or RDMA WRITE.
*/
static int
physical_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
int nsegs, bool writing)
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
rpcrdma_map_one(ia->ri_device, seg, rpcrdma_data_dir(writing));
seg->mr_rkey = ia->ri_dma_mr->rkey;
seg->mr_base = seg->mr_dma;
return 1;
}
/* Unmap a memory region, but leave it registered.
*/
static int
physical_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
rpcrdma_unmap_one(ia->ri_device, seg);
return 1;
}
/* DMA unmap all memory regions that were mapped for "req".
*/
static void
physical_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
{
struct ib_device *device = r_xprt->rx_ia.ri_device;
unsigned int i;
for (i = 0; req->rl_nchunks; --req->rl_nchunks)
rpcrdma_unmap_one(device, &req->rl_segments[i++]);
}
/* Use a slow, safe mechanism to invalidate all memory regions
* that were registered for "req".
*
* For physical memory registration, there is no good way to
* fence a single MR that has been advertised to the server. The
* client has already handed the server an R_key that cannot be
* invalidated and is shared by all MRs on this connection.
* Tearing down the PD might be the only safe choice, but it's
* not clear that a freshly acquired DMA R_key would be different
* than the one used by the PD that was just destroyed.
* FIXME.
*/
static void
physical_op_unmap_safe(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
bool sync)
{
physical_op_unmap_sync(r_xprt, req);
}
static void
physical_op_destroy(struct rpcrdma_buffer *buf)
{
}
const struct rpcrdma_memreg_ops rpcrdma_physical_memreg_ops = {
.ro_map = physical_op_map,
.ro_unmap_sync = physical_op_unmap_sync,
.ro_unmap_safe = physical_op_unmap_safe,
.ro_unmap = physical_op_unmap,
.ro_open = physical_op_open,
.ro_maxpages = physical_op_maxpages,
.ro_init = physical_op_init,
.ro_destroy = physical_op_destroy,
.ro_displayname = "physical",
};
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