net/sunrpc/xprtrdma/physical_ops.c

   1 /*
   2  * Copyright (c) 2015 Oracle.  All rights reserved.
   3  * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
   4  */
   5
   6 /* No-op chunk preparation. All client memory is pre-registered.
   7  * Sometimes referred to as ALLPHYSICAL mode.
   8  *
   9  * Physical registration is simple because all client memory is
  10  * pre-registered and never deregistered. This mode is good for
  11  * adapter bring up, but is considered not safe: the server is
  12  * trusted not to abuse its access to client memory not involved
  13  * in RDMA I/O.
  14  */
  15
  16 #include "xprt_rdma.h"
  17
  18 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  19 # define RPCDBG_FACILITY        RPCDBG_TRANS
  20 #endif
  21
  22 static int
  23 physical_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
  24                  struct rpcrdma_create_data_internal *cdata)
  25 {
  26         return 0;
  27 }
  28
  29 /* PHYSICAL memory registration conveys one page per chunk segment.
  30  */
  31 static size_t
  32 physical_op_maxpages(struct rpcrdma_xprt *r_xprt)
  33 {
  34         return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
  35                      rpcrdma_max_segments(r_xprt));
  36 }
  37
  38 static int
  39 physical_op_init(struct rpcrdma_xprt *r_xprt)
  40 {
  41         return 0;
  42 }
  43
  44 /* The client's physical memory is already exposed for
  45  * remote access via RDMA READ or RDMA WRITE.
  46  */
  47 static int
  48 physical_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
  49                 int nsegs, bool writing)
  50 {
  51         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
  52
  53         rpcrdma_map_one(ia->ri_device, seg, rpcrdma_data_dir(writing));
  54         seg->mr_rkey = ia->ri_bind_mem->rkey;
  55         seg->mr_base = seg->mr_dma;
  56         seg->mr_nsegs = 1;
  57         return 1;
  58 }
  59
  60 /* Unmap a memory region, but leave it registered.
  61  */
  62 static int
  63 physical_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
  64 {
  65         struct rpcrdma_ia *ia = &r_xprt->rx_ia;
  66
  67         rpcrdma_unmap_one(ia->ri_device, seg);
  68         return 1;
  69 }
  70
  71 static void
  72 physical_op_destroy(struct rpcrdma_buffer *buf)
  73 {
  74 }
  75
  76 const struct rpcrdma_memreg_ops rpcrdma_physical_memreg_ops = {
  77         .ro_map                         = physical_op_map,
  78         .ro_unmap                       = physical_op_unmap,
  79         .ro_open                        = physical_op_open,
  80         .ro_maxpages                    = physical_op_maxpages,
  81         .ro_init                        = physical_op_init,
  82         .ro_destroy                     = physical_op_destroy,
  83         .ro_displayname                 = "physical",
  84 };