net/smc/smc_ism.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Shared Memory Communications Direct over ISM devices (SMC-D)
   3  *
   4  * Functions for ISM device.
   5  *
   6  * Copyright IBM Corp. 2018
   7  */
   8
   9 #include <linux/spinlock.h>
  10 #include <linux/mutex.h>
  11 #include <linux/slab.h>
  12 #include <asm/page.h>
  13
  14 #include "smc.h"
  15 #include "smc_core.h"
  16 #include "smc_ism.h"
  17 #include "smc_pnet.h"
  18
  19 struct smcd_dev_list smcd_dev_list = {
  20         .list = LIST_HEAD_INIT(smcd_dev_list.list),
  21         .mutex = __MUTEX_INITIALIZER(smcd_dev_list.mutex)
  22 };
  23
  24 /* Test if an ISM communication is possible. */
  25 int smc_ism_cantalk(u64 peer_gid, unsigned short vlan_id, struct smcd_dev *smcd)
  26 {
  27         return smcd->ops->query_remote_gid(smcd, peer_gid, vlan_id ? 1 : 0,
  28                                            vlan_id);
  29 }
  30
  31 int smc_ism_write(struct smcd_dev *smcd, const struct smc_ism_position *pos,
  32                   void *data, size_t len)
  33 {
  34         int rc;
  35
  36         rc = smcd->ops->move_data(smcd, pos->token, pos->index, pos->signal,
  37                                   pos->offset, data, len);
  38
  39         return rc < 0 ? rc : 0;
  40 }
  41
  42 /* Set a connection using this DMBE. */
  43 void smc_ism_set_conn(struct smc_connection *conn)
  44 {
  45         unsigned long flags;
  46
  47         spin_lock_irqsave(&conn->lgr->smcd->lock, flags);
  48         conn->lgr->smcd->conn[conn->rmb_desc->sba_idx] = conn;
  49         spin_unlock_irqrestore(&conn->lgr->smcd->lock, flags);
  50 }
  51
  52 /* Unset a connection using this DMBE. */
  53 void smc_ism_unset_conn(struct smc_connection *conn)
  54 {
  55         unsigned long flags;
  56
  57         if (!conn->rmb_desc)
  58                 return;
  59
  60         spin_lock_irqsave(&conn->lgr->smcd->lock, flags);
  61         conn->lgr->smcd->conn[conn->rmb_desc->sba_idx] = NULL;
  62         spin_unlock_irqrestore(&conn->lgr->smcd->lock, flags);
  63 }
  64
  65 /* Register a VLAN identifier with the ISM device. Use a reference count
  66  * and add a VLAN identifier only when the first DMB using this VLAN is
  67  * registered.
  68  */
  69 int smc_ism_get_vlan(struct smcd_dev *smcd, unsigned short vlanid)
  70 {
  71         struct smc_ism_vlanid *new_vlan, *vlan;
  72         unsigned long flags;
  73         int rc = 0;
  74
  75         if (!vlanid)                    /* No valid vlan id */
  76                 return -EINVAL;
  77
  78         /* create new vlan entry, in case we need it */
  79         new_vlan = kzalloc(sizeof(*new_vlan), GFP_KERNEL);
  80         if (!new_vlan)
  81                 return -ENOMEM;
  82         new_vlan->vlanid = vlanid;
  83         refcount_set(&new_vlan->refcnt, 1);
  84
  85         /* if there is an existing entry, increase count and return */
  86         spin_lock_irqsave(&smcd->lock, flags);
  87         list_for_each_entry(vlan, &smcd->vlan, list) {
  88                 if (vlan->vlanid == vlanid) {
  89                         refcount_inc(&vlan->refcnt);
  90                         kfree(new_vlan);
  91                         goto out;
  92                 }
  93         }
  94
  95         /* no existing entry found.
  96          * add new entry to device; might fail, e.g., if HW limit reached
  97          */
  98         if (smcd->ops->add_vlan_id(smcd, vlanid)) {
  99                 kfree(new_vlan);
 100                 rc = -EIO;
 101                 goto out;
 102         }
 103         list_add_tail(&new_vlan->list, &smcd->vlan);
 104 out:
 105         spin_unlock_irqrestore(&smcd->lock, flags);
 106         return rc;
 107 }
 108
 109 /* Unregister a VLAN identifier with the ISM device. Use a reference count
 110  * and remove a VLAN identifier only when the last DMB using this VLAN is
 111  * unregistered.
 112  */
 113 int smc_ism_put_vlan(struct smcd_dev *smcd, unsigned short vlanid)
 114 {
 115         struct smc_ism_vlanid *vlan;
 116         unsigned long flags;
 117         bool found = false;
 118         int rc = 0;
 119
 120         if (!vlanid)                    /* No valid vlan id */
 121                 return -EINVAL;
 122
 123         spin_lock_irqsave(&smcd->lock, flags);
 124         list_for_each_entry(vlan, &smcd->vlan, list) {
 125                 if (vlan->vlanid == vlanid) {
 126                         if (!refcount_dec_and_test(&vlan->refcnt))
 127                                 goto out;
 128                         found = true;
 129                         break;
 130                 }
 131         }
 132         if (!found) {
 133                 rc = -ENOENT;
 134                 goto out;               /* VLAN id not in table */
 135         }
 136
 137         /* Found and the last reference just gone */
 138         if (smcd->ops->del_vlan_id(smcd, vlanid))
 139                 rc = -EIO;
 140         list_del(&vlan->list);
 141         kfree(vlan);
 142 out:
 143         spin_unlock_irqrestore(&smcd->lock, flags);
 144         return rc;
 145 }
 146
 147 int smc_ism_unregister_dmb(struct smcd_dev *smcd, struct smc_buf_desc *dmb_desc)
 148 {
 149         struct smcd_dmb dmb;
 150         int rc = 0;
 151
 152         if (!dmb_desc->dma_addr)
 153                 return rc;
 154
 155         memset(&dmb, 0, sizeof(dmb));
 156         dmb.dmb_tok = dmb_desc->token;
 157         dmb.sba_idx = dmb_desc->sba_idx;
 158         dmb.cpu_addr = dmb_desc->cpu_addr;
 159         dmb.dma_addr = dmb_desc->dma_addr;
 160         dmb.dmb_len = dmb_desc->len;
 161         rc = smcd->ops->unregister_dmb(smcd, &dmb);
 162         if (!rc || rc == ISM_ERROR) {
 163                 dmb_desc->cpu_addr = NULL;
 164                 dmb_desc->dma_addr = 0;
 165         }
 166
 167         return rc;
 168 }
 169
 170 int smc_ism_register_dmb(struct smc_link_group *lgr, int dmb_len,
 171                          struct smc_buf_desc *dmb_desc)
 172 {
 173         struct smcd_dmb dmb;
 174         int rc;
 175
 176         memset(&dmb, 0, sizeof(dmb));
 177         dmb.dmb_len = dmb_len;
 178         dmb.sba_idx = dmb_desc->sba_idx;
 179         dmb.vlan_id = lgr->vlan_id;
 180         dmb.rgid = lgr->peer_gid;
 181         rc = lgr->smcd->ops->register_dmb(lgr->smcd, &dmb);
 182         if (!rc) {
 183                 dmb_desc->sba_idx = dmb.sba_idx;
 184                 dmb_desc->token = dmb.dmb_tok;
 185                 dmb_desc->cpu_addr = dmb.cpu_addr;
 186                 dmb_desc->dma_addr = dmb.dma_addr;
 187                 dmb_desc->len = dmb.dmb_len;
 188         }
 189         return rc;
 190 }
 191
 192 struct smc_ism_event_work {
 193         struct work_struct work;
 194         struct smcd_dev *smcd;
 195         struct smcd_event event;
 196 };
 197
 198 #define ISM_EVENT_REQUEST               0x0001
 199 #define ISM_EVENT_RESPONSE              0x0002
 200 #define ISM_EVENT_REQUEST_IR            0x00000001
 201 #define ISM_EVENT_CODE_SHUTDOWN         0x80
 202 #define ISM_EVENT_CODE_TESTLINK         0x83
 203
 204 union smcd_sw_event_info {
 205         u64     info;
 206         struct {
 207                 u8              uid[SMC_LGR_ID_SIZE];
 208                 unsigned short  vlan_id;
 209                 u16             code;
 210         };
 211 };
 212
 213 static void smcd_handle_sw_event(struct smc_ism_event_work *wrk)
 214 {
 215         union smcd_sw_event_info ev_info;
 216
 217         ev_info.info = wrk->event.info;
 218         switch (wrk->event.code) {
 219         case ISM_EVENT_CODE_SHUTDOWN:   /* Peer shut down DMBs */
 220                 smc_smcd_terminate(wrk->smcd, wrk->event.tok, ev_info.vlan_id);
 221                 break;
 222         case ISM_EVENT_CODE_TESTLINK:   /* Activity timer */
 223                 if (ev_info.code == ISM_EVENT_REQUEST) {
 224                         ev_info.code = ISM_EVENT_RESPONSE;
 225                         wrk->smcd->ops->signal_event(wrk->smcd,
 226                                                      wrk->event.tok,
 227                                                      ISM_EVENT_REQUEST_IR,
 228                                                      ISM_EVENT_CODE_TESTLINK,
 229                                                      ev_info.info);
 230                         }
 231                 break;
 232         }
 233 }
 234
 235 int smc_ism_signal_shutdown(struct smc_link_group *lgr)
 236 {
 237         int rc;
 238         union smcd_sw_event_info ev_info;
 239
 240         if (lgr->peer_shutdown)
 241                 return 0;
 242
 243         memcpy(ev_info.uid, lgr->id, SMC_LGR_ID_SIZE);
 244         ev_info.vlan_id = lgr->vlan_id;
 245         ev_info.code = ISM_EVENT_REQUEST;
 246         rc = lgr->smcd->ops->signal_event(lgr->smcd, lgr->peer_gid,
 247                                           ISM_EVENT_REQUEST_IR,
 248                                           ISM_EVENT_CODE_SHUTDOWN,
 249                                           ev_info.info);
 250         return rc;
 251 }
 252
 253 /* worker for SMC-D events */
 254 static void smc_ism_event_work(struct work_struct *work)
 255 {
 256         struct smc_ism_event_work *wrk =
 257                 container_of(work, struct smc_ism_event_work, work);
 258
 259         switch (wrk->event.type) {
 260         case ISM_EVENT_GID:     /* GID event, token is peer GID */
 261                 smc_smcd_terminate(wrk->smcd, wrk->event.tok, VLAN_VID_MASK);
 262                 break;
 263         case ISM_EVENT_DMB:
 264                 break;
 265         case ISM_EVENT_SWR:     /* Software defined event */
 266                 smcd_handle_sw_event(wrk);
 267                 break;
 268         }
 269         kfree(wrk);
 270 }
 271
 272 static void smcd_release(struct device *dev)
 273 {
 274         struct smcd_dev *smcd = container_of(dev, struct smcd_dev, dev);
 275
 276         kfree(smcd->conn);
 277         kfree(smcd);
 278 }
 279
 280 struct smcd_dev *smcd_alloc_dev(struct device *parent, const char *name,
 281                                 const struct smcd_ops *ops, int max_dmbs)
 282 {
 283         struct smcd_dev *smcd;
 284
 285         smcd = kzalloc(sizeof(*smcd), GFP_KERNEL);
 286         if (!smcd)
 287                 return NULL;
 288         smcd->conn = kcalloc(max_dmbs, sizeof(struct smc_connection *),
 289                              GFP_KERNEL);
 290         if (!smcd->conn) {
 291                 kfree(smcd);
 292                 return NULL;
 293         }
 294
 295         smcd->dev.parent = parent;
 296         smcd->dev.release = smcd_release;
 297         device_initialize(&smcd->dev);
 298         dev_set_name(&smcd->dev, name);
 299         smcd->ops = ops;
 300         if (smc_pnetid_by_dev_port(parent, 0, smcd->pnetid))
 301                 smc_pnetid_by_table_smcd(smcd);
 302
 303         spin_lock_init(&smcd->lock);
 304         spin_lock_init(&smcd->lgr_lock);
 305         INIT_LIST_HEAD(&smcd->vlan);
 306         INIT_LIST_HEAD(&smcd->lgr_list);
 307         init_waitqueue_head(&smcd->lgrs_deleted);
 308         smcd->event_wq = alloc_ordered_workqueue("ism_evt_wq-%s)",
 309                                                  WQ_MEM_RECLAIM, name);
 310         if (!smcd->event_wq) {
 311                 kfree(smcd->conn);
 312                 kfree(smcd);
 313                 return NULL;
 314         }
 315         return smcd;
 316 }
 317 EXPORT_SYMBOL_GPL(smcd_alloc_dev);
 318
 319 int smcd_register_dev(struct smcd_dev *smcd)
 320 {
 321         mutex_lock(&smcd_dev_list.mutex);
 322         list_add_tail(&smcd->list, &smcd_dev_list.list);
 323         mutex_unlock(&smcd_dev_list.mutex);
 324
 325         pr_warn_ratelimited("smc: adding smcd device %s with pnetid %.16s%s\n",
 326                             dev_name(&smcd->dev), smcd->pnetid,
 327                             smcd->pnetid_by_user ? " (user defined)" : "");
 328
 329         return device_add(&smcd->dev);
 330 }
 331 EXPORT_SYMBOL_GPL(smcd_register_dev);
 332
 333 void smcd_unregister_dev(struct smcd_dev *smcd)
 334 {
 335         pr_warn_ratelimited("smc: removing smcd device %s\n",
 336                             dev_name(&smcd->dev));
 337         mutex_lock(&smcd_dev_list.mutex);
 338         list_del_init(&smcd->list);
 339         mutex_unlock(&smcd_dev_list.mutex);
 340         smcd->going_away = 1;
 341         smc_smcd_terminate_all(smcd);
 342         flush_workqueue(smcd->event_wq);
 343         destroy_workqueue(smcd->event_wq);
 344
 345         device_del(&smcd->dev);
 346 }
 347 EXPORT_SYMBOL_GPL(smcd_unregister_dev);
 348
 349 void smcd_free_dev(struct smcd_dev *smcd)
 350 {
 351         put_device(&smcd->dev);
 352 }
 353 EXPORT_SYMBOL_GPL(smcd_free_dev);
 354
 355 /* SMCD Device event handler. Called from ISM device interrupt handler.
 356  * Parameters are smcd device pointer,
 357  * - event->type (0 --> DMB, 1 --> GID),
 358  * - event->code (event code),
 359  * - event->tok (either DMB token when event type 0, or GID when event type 1)
 360  * - event->time (time of day)
 361  * - event->info (debug info).
 362  *
 363  * Context:
 364  * - Function called in IRQ context from ISM device driver event handler.
 365  */
 366 void smcd_handle_event(struct smcd_dev *smcd, struct smcd_event *event)
 367 {
 368         struct smc_ism_event_work *wrk;
 369
 370         if (smcd->going_away)
 371                 return;
 372         /* copy event to event work queue, and let it be handled there */
 373         wrk = kmalloc(sizeof(*wrk), GFP_ATOMIC);
 374         if (!wrk)
 375                 return;
 376         INIT_WORK(&wrk->work, smc_ism_event_work);
 377         wrk->smcd = smcd;
 378         wrk->event = *event;
 379         queue_work(smcd->event_wq, &wrk->work);
 380 }
 381 EXPORT_SYMBOL_GPL(smcd_handle_event);
 382
 383 /* SMCD Device interrupt handler. Called from ISM device interrupt handler.
 384  * Parameters are smcd device pointer and DMB number. Find the connection and
 385  * schedule the tasklet for this connection.
 386  *
 387  * Context:
 388  * - Function called in IRQ context from ISM device driver IRQ handler.
 389  */
 390 void smcd_handle_irq(struct smcd_dev *smcd, unsigned int dmbno)
 391 {
 392         struct smc_connection *conn = NULL;
 393         unsigned long flags;
 394
 395         spin_lock_irqsave(&smcd->lock, flags);
 396         conn = smcd->conn[dmbno];
 397         if (conn && !conn->killed)
 398                 tasklet_schedule(&conn->rx_tsklet);
 399         spin_unlock_irqrestore(&smcd->lock, flags);
 400 }
 401 EXPORT_SYMBOL_GPL(smcd_handle_irq);