blob: 52f9ad5fe19bb1e06c06c482a0afc80a146701e4 [file] [log] [blame]
Chuck Levera0ce85f2015-03-30 14:34:21 -04001/*
2 * Copyright (c) 2015 Oracle. All rights reserved.
3 * Copyright (c) 2003-2007 Network Appliance, Inc. All rights reserved.
4 */
5
6/* Lightweight memory registration using Fast Memory Regions (FMR).
7 * Referred to sometimes as MTHCAFMR mode.
8 *
9 * FMR uses synchronous memory registration and deregistration.
10 * FMR registration is known to be fast, but FMR deregistration
11 * can take tens of usecs to complete.
12 */
13
Chuck Leverfc7fbb52015-05-26 11:52:16 -040014/* Normal operation
15 *
16 * A Memory Region is prepared for RDMA READ or WRITE using the
17 * ib_map_phys_fmr verb (fmr_op_map). When the RDMA operation is
18 * finished, the Memory Region is unmapped using the ib_unmap_fmr
19 * verb (fmr_op_unmap).
20 */
21
22/* Transport recovery
23 *
24 * After a transport reconnect, fmr_op_map re-uses the MR already
25 * allocated for the RPC, but generates a fresh rkey then maps the
26 * MR again. This process is synchronous.
27 */
28
Chuck Levera0ce85f2015-03-30 14:34:21 -040029#include "xprt_rdma.h"
30
31#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
32# define RPCDBG_FACILITY RPCDBG_TRANS
33#endif
34
Chuck Lever1c9351e2015-03-30 14:34:30 -040035/* Maximum scatter/gather per FMR */
36#define RPCRDMA_MAX_FMR_SGES (64)
37
Chuck Lever3968cb52015-03-30 14:35:26 -040038static int
39fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
40 struct rpcrdma_create_data_internal *cdata)
41{
42 return 0;
43}
44
Chuck Lever1c9351e2015-03-30 14:34:30 -040045/* FMR mode conveys up to 64 pages of payload per chunk segment.
46 */
47static size_t
48fmr_op_maxpages(struct rpcrdma_xprt *r_xprt)
49{
50 return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
51 rpcrdma_max_segments(r_xprt) * RPCRDMA_MAX_FMR_SGES);
52}
53
Chuck Lever91e70e72015-03-30 14:34:58 -040054static int
55fmr_op_init(struct rpcrdma_xprt *r_xprt)
56{
57 struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
58 int mr_access_flags = IB_ACCESS_REMOTE_WRITE | IB_ACCESS_REMOTE_READ;
59 struct ib_fmr_attr fmr_attr = {
60 .max_pages = RPCRDMA_MAX_FMR_SGES,
61 .max_maps = 1,
62 .page_shift = PAGE_SHIFT
63 };
64 struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
65 struct rpcrdma_mw *r;
66 int i, rc;
67
Chuck Lever58d1dcf2015-05-26 11:53:13 -040068 spin_lock_init(&buf->rb_mwlock);
Chuck Lever91e70e72015-03-30 14:34:58 -040069 INIT_LIST_HEAD(&buf->rb_mws);
70 INIT_LIST_HEAD(&buf->rb_all);
71
72 i = (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS;
Linus Torvalds59953fb2015-04-26 17:33:59 -070073 dprintk("RPC: %s: initializing %d FMRs\n", __func__, i);
Chuck Lever91e70e72015-03-30 14:34:58 -040074
75 while (i--) {
76 r = kzalloc(sizeof(*r), GFP_KERNEL);
77 if (!r)
78 return -ENOMEM;
79
80 r->r.fmr = ib_alloc_fmr(pd, mr_access_flags, &fmr_attr);
81 if (IS_ERR(r->r.fmr))
82 goto out_fmr_err;
83
84 list_add(&r->mw_list, &buf->rb_mws);
85 list_add(&r->mw_all, &buf->rb_all);
86 }
87 return 0;
88
89out_fmr_err:
90 rc = PTR_ERR(r->r.fmr);
91 dprintk("RPC: %s: ib_alloc_fmr status %i\n", __func__, rc);
92 kfree(r);
93 return rc;
94}
95
Chuck Leverfc7fbb52015-05-26 11:52:16 -040096static int
97__fmr_unmap(struct rpcrdma_mw *r)
98{
99 LIST_HEAD(l);
100
101 list_add(&r->r.fmr->list, &l);
102 return ib_unmap_fmr(&l);
103}
104
Chuck Lever9c1b4d72015-03-30 14:34:39 -0400105/* Use the ib_map_phys_fmr() verb to register a memory region
106 * for remote access via RDMA READ or RDMA WRITE.
107 */
108static int
109fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
110 int nsegs, bool writing)
111{
112 struct rpcrdma_ia *ia = &r_xprt->rx_ia;
Chuck Lever89e0d1122015-05-26 11:51:56 -0400113 struct ib_device *device = ia->ri_device;
Chuck Leverd6547882015-03-30 14:35:44 -0400114 enum dma_data_direction direction = rpcrdma_data_dir(writing);
Chuck Lever9c1b4d72015-03-30 14:34:39 -0400115 struct rpcrdma_mr_seg *seg1 = seg;
Chuck Lever9c1b4d72015-03-30 14:34:39 -0400116 u64 physaddrs[RPCRDMA_MAX_DATA_SEGS];
117 int len, pageoff, i, rc;
Chuck Leverfc7fbb52015-05-26 11:52:16 -0400118 struct rpcrdma_mw *mw;
119
120 mw = seg1->rl_mw;
121 seg1->rl_mw = NULL;
122 if (!mw) {
123 mw = rpcrdma_get_mw(r_xprt);
124 if (!mw)
125 return -ENOMEM;
126 } else {
127 /* this is a retransmit; generate a fresh rkey */
128 rc = __fmr_unmap(mw);
129 if (rc)
130 return rc;
131 }
Chuck Lever9c1b4d72015-03-30 14:34:39 -0400132
133 pageoff = offset_in_page(seg1->mr_offset);
134 seg1->mr_offset -= pageoff; /* start of page */
135 seg1->mr_len += pageoff;
136 len = -pageoff;
137 if (nsegs > RPCRDMA_MAX_FMR_SGES)
138 nsegs = RPCRDMA_MAX_FMR_SGES;
139 for (i = 0; i < nsegs;) {
Chuck Leverd6547882015-03-30 14:35:44 -0400140 rpcrdma_map_one(device, seg, direction);
Chuck Lever9c1b4d72015-03-30 14:34:39 -0400141 physaddrs[i] = seg->mr_dma;
142 len += seg->mr_len;
143 ++seg;
144 ++i;
145 /* Check for holes */
146 if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
147 offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
148 break;
149 }
150
151 rc = ib_map_phys_fmr(mw->r.fmr, physaddrs, i, seg1->mr_dma);
152 if (rc)
153 goto out_maperr;
154
Chuck Leverfc7fbb52015-05-26 11:52:16 -0400155 seg1->rl_mw = mw;
Chuck Lever9c1b4d72015-03-30 14:34:39 -0400156 seg1->mr_rkey = mw->r.fmr->rkey;
157 seg1->mr_base = seg1->mr_dma + pageoff;
158 seg1->mr_nsegs = i;
159 seg1->mr_len = len;
160 return i;
161
162out_maperr:
163 dprintk("RPC: %s: ib_map_phys_fmr %u@0x%llx+%i (%d) status %i\n",
164 __func__, len, (unsigned long long)seg1->mr_dma,
165 pageoff, i, rc);
166 while (i--)
Chuck Leverd6547882015-03-30 14:35:44 -0400167 rpcrdma_unmap_one(device, --seg);
Chuck Lever9c1b4d72015-03-30 14:34:39 -0400168 return rc;
169}
170
Chuck Lever6814bae2015-03-30 14:34:48 -0400171/* Use the ib_unmap_fmr() verb to prevent further remote
172 * access via RDMA READ or RDMA WRITE.
173 */
174static int
175fmr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
176{
177 struct rpcrdma_ia *ia = &r_xprt->rx_ia;
178 struct rpcrdma_mr_seg *seg1 = seg;
Chuck Leverfc7fbb52015-05-26 11:52:16 -0400179 struct rpcrdma_mw *mw = seg1->rl_mw;
Chuck Lever6814bae2015-03-30 14:34:48 -0400180 int rc, nsegs = seg->mr_nsegs;
Chuck Lever6814bae2015-03-30 14:34:48 -0400181
Chuck Leverfc7fbb52015-05-26 11:52:16 -0400182 dprintk("RPC: %s: FMR %p\n", __func__, mw);
183
184 seg1->rl_mw = NULL;
Chuck Lever6814bae2015-03-30 14:34:48 -0400185 while (seg1->mr_nsegs--)
Chuck Lever89e0d1122015-05-26 11:51:56 -0400186 rpcrdma_unmap_one(ia->ri_device, seg++);
Chuck Leverfc7fbb52015-05-26 11:52:16 -0400187 rc = __fmr_unmap(mw);
Chuck Lever6814bae2015-03-30 14:34:48 -0400188 if (rc)
189 goto out_err;
Chuck Leverfc7fbb52015-05-26 11:52:16 -0400190 rpcrdma_put_mw(r_xprt, mw);
Chuck Lever6814bae2015-03-30 14:34:48 -0400191 return nsegs;
192
193out_err:
Chuck Leverfc7fbb52015-05-26 11:52:16 -0400194 /* The FMR is abandoned, but remains in rb_all. fmr_op_destroy
195 * will attempt to release it when the transport is destroyed.
196 */
Chuck Lever6814bae2015-03-30 14:34:48 -0400197 dprintk("RPC: %s: ib_unmap_fmr status %i\n", __func__, rc);
198 return nsegs;
199}
200
Chuck Lever4561f342015-03-30 14:35:17 -0400201static void
202fmr_op_destroy(struct rpcrdma_buffer *buf)
203{
204 struct rpcrdma_mw *r;
205 int rc;
206
207 while (!list_empty(&buf->rb_all)) {
208 r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
209 list_del(&r->mw_all);
210 rc = ib_dealloc_fmr(r->r.fmr);
211 if (rc)
212 dprintk("RPC: %s: ib_dealloc_fmr failed %i\n",
213 __func__, rc);
214 kfree(r);
215 }
216}
217
Chuck Levera0ce85f2015-03-30 14:34:21 -0400218const struct rpcrdma_memreg_ops rpcrdma_fmr_memreg_ops = {
Chuck Lever9c1b4d72015-03-30 14:34:39 -0400219 .ro_map = fmr_op_map,
Chuck Lever6814bae2015-03-30 14:34:48 -0400220 .ro_unmap = fmr_op_unmap,
Chuck Lever3968cb52015-03-30 14:35:26 -0400221 .ro_open = fmr_op_open,
Chuck Lever1c9351e2015-03-30 14:34:30 -0400222 .ro_maxpages = fmr_op_maxpages,
Chuck Lever91e70e72015-03-30 14:34:58 -0400223 .ro_init = fmr_op_init,
Chuck Lever4561f342015-03-30 14:35:17 -0400224 .ro_destroy = fmr_op_destroy,
Chuck Levera0ce85f2015-03-30 14:34:21 -0400225 .ro_displayname = "fmr",
226};