[infiniband] Do not use GRH for local paths
[ipxe.git] / src / net / infiniband / ib_pathrec.c
1 /*
2 * Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <byteswap.h>
30 #include <errno.h>
31 #include <ipxe/infiniband.h>
32 #include <ipxe/ib_mi.h>
33 #include <ipxe/ib_pathrec.h>
34
35 /** @file
36 *
37 * Infiniband path lookups
38 *
39 */
40
41 /**
42 * Handle path transaction completion
43 *
44 * @v ibdev Infiniband device
45 * @v mi Management interface
46 * @v madx Management transaction
47 * @v rc Status code
48 * @v mad Received MAD (or NULL on error)
49 * @v av Source address vector (or NULL on error)
50 */
51 static void ib_path_complete ( struct ib_device *ibdev,
52 struct ib_mad_interface *mi,
53 struct ib_mad_transaction *madx,
54 int rc, union ib_mad *mad,
55 struct ib_address_vector *av __unused ) {
56 struct ib_path *path = ib_madx_get_ownerdata ( madx );
57 union ib_gid *dgid = &path->av.gid;
58 struct ib_path_record *pathrec = &mad->sa.sa_data.path_record;
59
60 /* Report failures */
61 if ( ( rc == 0 ) && ( mad->hdr.status != htons ( IB_MGMT_STATUS_OK ) ))
62 rc = -ENETUNREACH;
63 if ( rc != 0 ) {
64 DBGC ( ibdev, "IBDEV %s path lookup for " IB_GID_FMT
65 " failed: %s\n",
66 ibdev->name, IB_GID_ARGS ( dgid ), strerror ( rc ) );
67 goto out;
68 }
69
70 /* Extract values from MAD */
71 path->av.lid = ntohs ( pathrec->dlid );
72 path->av.sl = ( pathrec->reserved__sl & 0x0f );
73 path->av.rate = ( pathrec->rate_selector__rate & 0x3f );
74 DBGC ( ibdev, "IBDEV %s path to " IB_GID_FMT " lid %d sl %d rate "
75 "%d\n", ibdev->name, IB_GID_ARGS ( dgid ), path->av.lid,
76 path->av.sl, path->av.rate );
77
78 /* Use only the LID if no GRH is needed for this path */
79 if ( memcmp ( &path->av.gid.s.prefix, &ibdev->gid.s.prefix,
80 sizeof ( path->av.gid.s.prefix ) ) == 0 ) {
81 path->av.gid_present = 0;
82 }
83
84 out:
85 /* Destroy the completed transaction */
86 ib_destroy_madx ( ibdev, mi, madx );
87 path->madx = NULL;
88
89 /* Hand off to upper completion handler */
90 path->op->complete ( ibdev, path, rc, &path->av );
91 }
92
93 /** Path transaction completion operations */
94 static struct ib_mad_transaction_operations ib_path_op = {
95 .complete = ib_path_complete,
96 };
97
98 /**
99 * Create path
100 *
101 * @v ibdev Infiniband device
102 * @v av Address vector to complete
103 * @v op Path operations
104 * @ret path Path
105 */
106 struct ib_path *
107 ib_create_path ( struct ib_device *ibdev, struct ib_address_vector *av,
108 struct ib_path_operations *op ) {
109 struct ib_path *path;
110 union ib_mad mad;
111 struct ib_mad_sa *sa = &mad.sa;
112
113 /* Allocate and initialise structure */
114 path = zalloc ( sizeof ( *path ) );
115 if ( ! path )
116 goto err_alloc_path;
117 path->ibdev = ibdev;
118 memcpy ( &path->av, av, sizeof ( path->av ) );
119 path->op = op;
120
121 /* Construct path request */
122 memset ( sa, 0, sizeof ( *sa ) );
123 sa->mad_hdr.mgmt_class = IB_MGMT_CLASS_SUBN_ADM;
124 sa->mad_hdr.class_version = IB_SA_CLASS_VERSION;
125 sa->mad_hdr.method = IB_MGMT_METHOD_GET;
126 sa->mad_hdr.attr_id = htons ( IB_SA_ATTR_PATH_REC );
127 sa->sa_hdr.comp_mask[1] =
128 htonl ( IB_SA_PATH_REC_DGID | IB_SA_PATH_REC_SGID );
129 memcpy ( &sa->sa_data.path_record.dgid, &path->av.gid,
130 sizeof ( sa->sa_data.path_record.dgid ) );
131 memcpy ( &sa->sa_data.path_record.sgid, &ibdev->gid,
132 sizeof ( sa->sa_data.path_record.sgid ) );
133
134 /* Create management transaction */
135 path->madx = ib_create_madx ( ibdev, ibdev->gsi, &mad, NULL,
136 &ib_path_op );
137 if ( ! path->madx )
138 goto err_create_madx;
139 ib_madx_set_ownerdata ( path->madx, path );
140
141 return path;
142
143 ib_destroy_madx ( ibdev, ibdev->gsi, path->madx );
144 err_create_madx:
145 free ( path );
146 err_alloc_path:
147 return NULL;
148 }
149
150 /**
151 * Destroy path
152 *
153 * @v ibdev Infiniband device
154 * @v path Path
155 */
156 void ib_destroy_path ( struct ib_device *ibdev, struct ib_path *path ) {
157
158 if ( path->madx )
159 ib_destroy_madx ( ibdev, ibdev->gsi, path->madx );
160 free ( path );
161 }
162
163 /** Number of path cache entries
164 *
165 * Must be a power of two.
166 */
167 #define IB_NUM_CACHED_PATHS 4
168
169 /** A cached path */
170 struct ib_cached_path {
171 /** Path */
172 struct ib_path *path;
173 };
174
175 /** Path cache */
176 static struct ib_cached_path ib_path_cache[IB_NUM_CACHED_PATHS];
177
178 /** Oldest path cache entry index */
179 static unsigned int ib_path_cache_idx;
180
181 /**
182 * Find path cache entry
183 *
184 * @v ibdev Infiniband device
185 * @v dgid Destination GID
186 * @ret path Path cache entry, or NULL
187 */
188 static struct ib_cached_path *
189 ib_find_path_cache_entry ( struct ib_device *ibdev, union ib_gid *dgid ) {
190 struct ib_cached_path *cached;
191 unsigned int i;
192
193 for ( i = 0 ; i < IB_NUM_CACHED_PATHS ; i++ ) {
194 cached = &ib_path_cache[i];
195 if ( ! cached->path )
196 continue;
197 if ( cached->path->ibdev != ibdev )
198 continue;
199 if ( memcmp ( &cached->path->av.gid, dgid,
200 sizeof ( cached->path->av.gid ) ) != 0 )
201 continue;
202 return cached;
203 }
204
205 return NULL;
206 }
207
208 /**
209 * Handle cached path transaction completion
210 *
211 * @v ibdev Infiniband device
212 * @v path Path
213 * @v rc Status code
214 * @v av Address vector, or NULL on error
215 */
216 static void ib_cached_path_complete ( struct ib_device *ibdev,
217 struct ib_path *path, int rc,
218 struct ib_address_vector *av __unused ) {
219 struct ib_cached_path *cached = ib_path_get_ownerdata ( path );
220
221 /* If the transaction failed, erase the cache entry */
222 if ( rc != 0 ) {
223 /* Destroy the old cache entry */
224 ib_destroy_path ( ibdev, path );
225 memset ( cached, 0, sizeof ( *cached ) );
226 return;
227 }
228
229 /* Do not destroy the completed transaction; we still need to
230 * refer to the resolved path.
231 */
232 }
233
234 /** Cached path transaction completion operations */
235 static struct ib_path_operations ib_cached_path_op = {
236 .complete = ib_cached_path_complete,
237 };
238
239 /**
240 * Resolve path
241 *
242 * @v ibdev Infiniband device
243 * @v av Address vector to complete
244 * @ret rc Return status code
245 *
246 * This provides a non-transactional way to resolve a path, via a
247 * cache similar to ARP.
248 */
249 int ib_resolve_path ( struct ib_device *ibdev, struct ib_address_vector *av ) {
250 union ib_gid *gid = &av->gid;
251 struct ib_cached_path *cached;
252 unsigned int cache_idx;
253
254 /* Look in cache for a matching entry */
255 cached = ib_find_path_cache_entry ( ibdev, gid );
256 if ( cached && cached->path->av.lid ) {
257 /* Populated entry found */
258 av->lid = cached->path->av.lid;
259 av->rate = cached->path->av.rate;
260 av->sl = cached->path->av.sl;
261 DBGC2 ( ibdev, "IBDEV %s cache hit for " IB_GID_FMT "\n",
262 ibdev->name, IB_GID_ARGS ( gid ) );
263 return 0;
264 }
265 DBGC ( ibdev, "IBDEV %s cache miss for " IB_GID_FMT "%s\n", ibdev->name,
266 IB_GID_ARGS ( gid ), ( cached ? " (in progress)" : "" ) );
267
268 /* If lookup is already in progress, do nothing */
269 if ( cached )
270 return -ENOENT;
271
272 /* Locate a new cache entry to use */
273 cache_idx = ( (ib_path_cache_idx++) % IB_NUM_CACHED_PATHS );
274 cached = &ib_path_cache[cache_idx];
275
276 /* Destroy the old cache entry */
277 if ( cached->path )
278 ib_destroy_path ( ibdev, cached->path );
279 memset ( cached, 0, sizeof ( *cached ) );
280
281 /* Create new path */
282 cached->path = ib_create_path ( ibdev, av, &ib_cached_path_op );
283 if ( ! cached->path ) {
284 DBGC ( ibdev, "IBDEV %s could not create path\n",
285 ibdev->name );
286 return -ENOMEM;
287 }
288 ib_path_set_ownerdata ( cached->path, cached );
289
290 /* Not found yet */
291 return -ENOENT;
292 }