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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Shared Memory Communications Direct over loopback-ism device.
4 *
5 * Functions for loopback-ism device.
6 *
7 * Copyright (c) 2024, Alibaba Inc.
8 *
9 * Author: Wen Gu <guwen@linux.alibaba.com>
10 * Tony Lu <tonylu@linux.alibaba.com>
11 *
12 */
13
14#include <linux/device.h>
15#include <linux/types.h>
16#include <net/smc.h>
17
18#include "smc_cdc.h"
19#include "smc_ism.h"
20#include "smc_loopback.h"
21
22#define SMC_LO_V2_CAPABLE 0x1 /* loopback-ism acts as ISMv2 */
23#define SMC_LO_SUPPORT_NOCOPY 0x1
24#define SMC_DMA_ADDR_INVALID (~(dma_addr_t)0)
25
26static const char smc_lo_dev_name[] = "loopback-ism";
27static struct smc_lo_dev *lo_dev;
28
29static void smc_lo_generate_ids(struct smc_lo_dev *ldev)
30{
31 struct smcd_gid *lgid = &ldev->local_gid;
32 uuid_t uuid;
33
34 uuid_gen(&uuid);
35 memcpy(&lgid->gid, &uuid, sizeof(lgid->gid));
36 memcpy(&lgid->gid_ext, (u8 *)&uuid + sizeof(lgid->gid),
37 sizeof(lgid->gid_ext));
38
39 ldev->chid = SMC_LO_RESERVED_CHID;
40}
41
42static int smc_lo_query_rgid(struct smcd_dev *smcd, struct smcd_gid *rgid,
43 u32 vid_valid, u32 vid)
44{
45 struct smc_lo_dev *ldev = smcd->priv;
46
47 /* rgid should be the same as lgid */
48 if (!ldev || rgid->gid != ldev->local_gid.gid ||
49 rgid->gid_ext != ldev->local_gid.gid_ext)
50 return -ENETUNREACH;
51 return 0;
52}
53
54static int smc_lo_register_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb,
55 void *client_priv)
56{
57 struct smc_lo_dmb_node *dmb_node, *tmp_node;
58 struct smc_lo_dev *ldev = smcd->priv;
59 int sba_idx, rc;
60
61 /* check space for new dmb */
62 for_each_clear_bit(sba_idx, ldev->sba_idx_mask, SMC_LO_MAX_DMBS) {
63 if (!test_and_set_bit(sba_idx, ldev->sba_idx_mask))
64 break;
65 }
66 if (sba_idx == SMC_LO_MAX_DMBS)
67 return -ENOSPC;
68
69 dmb_node = kzalloc(sizeof(*dmb_node), GFP_KERNEL);
70 if (!dmb_node) {
71 rc = -ENOMEM;
72 goto err_bit;
73 }
74
75 dmb_node->sba_idx = sba_idx;
76 dmb_node->len = dmb->dmb_len;
77 dmb_node->cpu_addr = kzalloc(dmb_node->len, GFP_KERNEL |
78 __GFP_NOWARN | __GFP_NORETRY |
79 __GFP_NOMEMALLOC);
80 if (!dmb_node->cpu_addr) {
81 rc = -ENOMEM;
82 goto err_node;
83 }
84 dmb_node->dma_addr = SMC_DMA_ADDR_INVALID;
85 refcount_set(&dmb_node->refcnt, 1);
86
87again:
88 /* add new dmb into hash table */
89 get_random_bytes(&dmb_node->token, sizeof(dmb_node->token));
90 write_lock_bh(&ldev->dmb_ht_lock);
91 hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_node->token) {
92 if (tmp_node->token == dmb_node->token) {
93 write_unlock_bh(&ldev->dmb_ht_lock);
94 goto again;
95 }
96 }
97 hash_add(ldev->dmb_ht, &dmb_node->list, dmb_node->token);
98 write_unlock_bh(&ldev->dmb_ht_lock);
99 atomic_inc(&ldev->dmb_cnt);
100
101 dmb->sba_idx = dmb_node->sba_idx;
102 dmb->dmb_tok = dmb_node->token;
103 dmb->cpu_addr = dmb_node->cpu_addr;
104 dmb->dma_addr = dmb_node->dma_addr;
105 dmb->dmb_len = dmb_node->len;
106
107 return 0;
108
109err_node:
110 kfree(dmb_node);
111err_bit:
112 clear_bit(sba_idx, ldev->sba_idx_mask);
113 return rc;
114}
115
116static void __smc_lo_unregister_dmb(struct smc_lo_dev *ldev,
117 struct smc_lo_dmb_node *dmb_node)
118{
119 /* remove dmb from hash table */
120 write_lock_bh(&ldev->dmb_ht_lock);
121 hash_del(&dmb_node->list);
122 write_unlock_bh(&ldev->dmb_ht_lock);
123
124 clear_bit(dmb_node->sba_idx, ldev->sba_idx_mask);
125 kvfree(dmb_node->cpu_addr);
126 kfree(dmb_node);
127
128 if (atomic_dec_and_test(&ldev->dmb_cnt))
129 wake_up(&ldev->ldev_release);
130}
131
132static int smc_lo_unregister_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
133{
134 struct smc_lo_dmb_node *dmb_node = NULL, *tmp_node;
135 struct smc_lo_dev *ldev = smcd->priv;
136
137 /* find dmb from hash table */
138 read_lock_bh(&ldev->dmb_ht_lock);
139 hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb->dmb_tok) {
140 if (tmp_node->token == dmb->dmb_tok) {
141 dmb_node = tmp_node;
142 break;
143 }
144 }
145 if (!dmb_node) {
146 read_unlock_bh(&ldev->dmb_ht_lock);
147 return -EINVAL;
148 }
149 read_unlock_bh(&ldev->dmb_ht_lock);
150
151 if (refcount_dec_and_test(&dmb_node->refcnt))
152 __smc_lo_unregister_dmb(ldev, dmb_node);
153 return 0;
154}
155
156static int smc_lo_support_dmb_nocopy(struct smcd_dev *smcd)
157{
158 return SMC_LO_SUPPORT_NOCOPY;
159}
160
161static int smc_lo_attach_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
162{
163 struct smc_lo_dmb_node *dmb_node = NULL, *tmp_node;
164 struct smc_lo_dev *ldev = smcd->priv;
165
166 /* find dmb_node according to dmb->dmb_tok */
167 read_lock_bh(&ldev->dmb_ht_lock);
168 hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb->dmb_tok) {
169 if (tmp_node->token == dmb->dmb_tok) {
170 dmb_node = tmp_node;
171 break;
172 }
173 }
174 if (!dmb_node) {
175 read_unlock_bh(&ldev->dmb_ht_lock);
176 return -EINVAL;
177 }
178 read_unlock_bh(&ldev->dmb_ht_lock);
179
180 if (!refcount_inc_not_zero(&dmb_node->refcnt))
181 /* the dmb is being unregistered, but has
182 * not been removed from the hash table.
183 */
184 return -EINVAL;
185
186 /* provide dmb information */
187 dmb->sba_idx = dmb_node->sba_idx;
188 dmb->dmb_tok = dmb_node->token;
189 dmb->cpu_addr = dmb_node->cpu_addr;
190 dmb->dma_addr = dmb_node->dma_addr;
191 dmb->dmb_len = dmb_node->len;
192 return 0;
193}
194
195static int smc_lo_detach_dmb(struct smcd_dev *smcd, u64 token)
196{
197 struct smc_lo_dmb_node *dmb_node = NULL, *tmp_node;
198 struct smc_lo_dev *ldev = smcd->priv;
199
200 /* find dmb_node according to dmb->dmb_tok */
201 read_lock_bh(&ldev->dmb_ht_lock);
202 hash_for_each_possible(ldev->dmb_ht, tmp_node, list, token) {
203 if (tmp_node->token == token) {
204 dmb_node = tmp_node;
205 break;
206 }
207 }
208 if (!dmb_node) {
209 read_unlock_bh(&ldev->dmb_ht_lock);
210 return -EINVAL;
211 }
212 read_unlock_bh(&ldev->dmb_ht_lock);
213
214 if (refcount_dec_and_test(&dmb_node->refcnt))
215 __smc_lo_unregister_dmb(ldev, dmb_node);
216 return 0;
217}
218
219static int smc_lo_move_data(struct smcd_dev *smcd, u64 dmb_tok,
220 unsigned int idx, bool sf, unsigned int offset,
221 void *data, unsigned int size)
222{
223 struct smc_lo_dmb_node *rmb_node = NULL, *tmp_node;
224 struct smc_lo_dev *ldev = smcd->priv;
225 struct smc_connection *conn;
226
227 if (!sf)
228 /* since sndbuf is merged with peer DMB, there is
229 * no need to copy data from sndbuf to peer DMB.
230 */
231 return 0;
232
233 read_lock_bh(&ldev->dmb_ht_lock);
234 hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_tok) {
235 if (tmp_node->token == dmb_tok) {
236 rmb_node = tmp_node;
237 break;
238 }
239 }
240 if (!rmb_node) {
241 read_unlock_bh(&ldev->dmb_ht_lock);
242 return -EINVAL;
243 }
244 memcpy((char *)rmb_node->cpu_addr + offset, data, size);
245 read_unlock_bh(&ldev->dmb_ht_lock);
246
247 conn = smcd->conn[rmb_node->sba_idx];
248 if (!conn || conn->killed)
249 return -EPIPE;
250 tasklet_schedule(&conn->rx_tsklet);
251 return 0;
252}
253
254static int smc_lo_supports_v2(void)
255{
256 return SMC_LO_V2_CAPABLE;
257}
258
259static void smc_lo_get_local_gid(struct smcd_dev *smcd,
260 struct smcd_gid *smcd_gid)
261{
262 struct smc_lo_dev *ldev = smcd->priv;
263
264 smcd_gid->gid = ldev->local_gid.gid;
265 smcd_gid->gid_ext = ldev->local_gid.gid_ext;
266}
267
268static u16 smc_lo_get_chid(struct smcd_dev *smcd)
269{
270 return ((struct smc_lo_dev *)smcd->priv)->chid;
271}
272
273static struct device *smc_lo_get_dev(struct smcd_dev *smcd)
274{
275 return &((struct smc_lo_dev *)smcd->priv)->dev;
276}
277
278static const struct smcd_ops lo_ops = {
279 .query_remote_gid = smc_lo_query_rgid,
280 .register_dmb = smc_lo_register_dmb,
281 .unregister_dmb = smc_lo_unregister_dmb,
282 .support_dmb_nocopy = smc_lo_support_dmb_nocopy,
283 .attach_dmb = smc_lo_attach_dmb,
284 .detach_dmb = smc_lo_detach_dmb,
285 .add_vlan_id = NULL,
286 .del_vlan_id = NULL,
287 .set_vlan_required = NULL,
288 .reset_vlan_required = NULL,
289 .signal_event = NULL,
290 .move_data = smc_lo_move_data,
291 .supports_v2 = smc_lo_supports_v2,
292 .get_local_gid = smc_lo_get_local_gid,
293 .get_chid = smc_lo_get_chid,
294 .get_dev = smc_lo_get_dev,
295};
296
297static struct smcd_dev *smcd_lo_alloc_dev(const struct smcd_ops *ops,
298 int max_dmbs)
299{
300 struct smcd_dev *smcd;
301
302 smcd = kzalloc(sizeof(*smcd), GFP_KERNEL);
303 if (!smcd)
304 return NULL;
305
306 smcd->conn = kcalloc(max_dmbs, sizeof(struct smc_connection *),
307 GFP_KERNEL);
308 if (!smcd->conn)
309 goto out_smcd;
310
311 smcd->ops = ops;
312
313 spin_lock_init(&smcd->lock);
314 spin_lock_init(&smcd->lgr_lock);
315 INIT_LIST_HEAD(&smcd->vlan);
316 INIT_LIST_HEAD(&smcd->lgr_list);
317 init_waitqueue_head(&smcd->lgrs_deleted);
318 return smcd;
319
320out_smcd:
321 kfree(smcd);
322 return NULL;
323}
324
325static int smcd_lo_register_dev(struct smc_lo_dev *ldev)
326{
327 struct smcd_dev *smcd;
328
329 smcd = smcd_lo_alloc_dev(&lo_ops, SMC_LO_MAX_DMBS);
330 if (!smcd)
331 return -ENOMEM;
332 ldev->smcd = smcd;
333 smcd->priv = ldev;
334 smc_ism_set_v2_capable();
335 mutex_lock(&smcd_dev_list.mutex);
336 list_add(&smcd->list, &smcd_dev_list.list);
337 mutex_unlock(&smcd_dev_list.mutex);
338 pr_warn_ratelimited("smc: adding smcd device %s\n",
339 dev_name(&ldev->dev));
340 return 0;
341}
342
343static void smcd_lo_unregister_dev(struct smc_lo_dev *ldev)
344{
345 struct smcd_dev *smcd = ldev->smcd;
346
347 pr_warn_ratelimited("smc: removing smcd device %s\n",
348 dev_name(&ldev->dev));
349 smcd->going_away = 1;
350 smc_smcd_terminate_all(smcd);
351 mutex_lock(&smcd_dev_list.mutex);
352 list_del_init(&smcd->list);
353 mutex_unlock(&smcd_dev_list.mutex);
354 kfree(smcd->conn);
355 kfree(smcd);
356}
357
358static int smc_lo_dev_init(struct smc_lo_dev *ldev)
359{
360 smc_lo_generate_ids(ldev);
361 rwlock_init(&ldev->dmb_ht_lock);
362 hash_init(ldev->dmb_ht);
363 atomic_set(&ldev->dmb_cnt, 0);
364 init_waitqueue_head(&ldev->ldev_release);
365
366 return smcd_lo_register_dev(ldev);
367}
368
369static void smc_lo_dev_exit(struct smc_lo_dev *ldev)
370{
371 smcd_lo_unregister_dev(ldev);
372 if (atomic_read(&ldev->dmb_cnt))
373 wait_event(ldev->ldev_release, !atomic_read(&ldev->dmb_cnt));
374}
375
376static void smc_lo_dev_release(struct device *dev)
377{
378 struct smc_lo_dev *ldev =
379 container_of(dev, struct smc_lo_dev, dev);
380
381 kfree(ldev);
382}
383
384static int smc_lo_dev_probe(void)
385{
386 struct smc_lo_dev *ldev;
387 int ret;
388
389 ldev = kzalloc(sizeof(*ldev), GFP_KERNEL);
390 if (!ldev)
391 return -ENOMEM;
392
393 ldev->dev.parent = NULL;
394 ldev->dev.release = smc_lo_dev_release;
395 device_initialize(&ldev->dev);
396 dev_set_name(&ldev->dev, smc_lo_dev_name);
397
398 ret = smc_lo_dev_init(ldev);
399 if (ret)
400 goto free_dev;
401
402 lo_dev = ldev; /* global loopback device */
403 return 0;
404
405free_dev:
406 put_device(&ldev->dev);
407 return ret;
408}
409
410static void smc_lo_dev_remove(void)
411{
412 if (!lo_dev)
413 return;
414
415 smc_lo_dev_exit(lo_dev);
416 put_device(&lo_dev->dev); /* device_initialize in smc_lo_dev_probe */
417}
418
419int smc_loopback_init(void)
420{
421 return smc_lo_dev_probe();
422}
423
424void smc_loopback_exit(void)
425{
426 smc_lo_dev_remove();
427}