git.oblomov.eu Git - linux-2.6/blob - drivers/infiniband/hw/ehca/ehca_irq.c

   1 /*
   2  *  IBM eServer eHCA Infiniband device driver for Linux on POWER
   3  *
   4  *  Functions for EQs, NEQs and interrupts
   5  *
   6  *  Authors: Heiko J Schick <schickhj@de.ibm.com>
   7  *           Khadija Souissi <souissi@de.ibm.com>
   8  *
   9  *  Copyright (c) 2005 IBM Corporation
  10  *
  11  *  All rights reserved.
  12  *
  13  *  This source code is distributed under a dual license of GPL v2.0 and OpenIB
  14  *  BSD.
  15  *
  16  * OpenIB BSD License
  17  *
  18  * Redistribution and use in source and binary forms, with or without
  19  * modification, are permitted provided that the following conditions are met:
  20  *
  21  * Redistributions of source code must retain the above copyright notice, this
  22  * list of conditions and the following disclaimer.
  23  *
  24  * Redistributions in binary form must reproduce the above copyright notice,
  25  * this list of conditions and the following disclaimer in the documentation
  26  * and/or other materials
  27  * provided with the distribution.
  28  *
  29  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  30  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  32  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  33  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  34  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  35  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  36  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
  37  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  38  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  39  * POSSIBILITY OF SUCH DAMAGE.
  40  */
  41
  42 #include "ehca_classes.h"
  43 #include "ehca_irq.h"
  44 #include "ehca_iverbs.h"
  45 #include "ehca_tools.h"
  46 #include "hcp_if.h"
  47 #include "hipz_fns.h"
  48 #include "ipz_pt_fn.h"
  49
  50 #define EQE_COMPLETION_EVENT   EHCA_BMASK_IBM(1,1)
  51 #define EQE_CQ_QP_NUMBER       EHCA_BMASK_IBM(8,31)
  52 #define EQE_EE_IDENTIFIER      EHCA_BMASK_IBM(2,7)
  53 #define EQE_CQ_NUMBER          EHCA_BMASK_IBM(8,31)
  54 #define EQE_QP_NUMBER          EHCA_BMASK_IBM(8,31)
  55 #define EQE_QP_TOKEN           EHCA_BMASK_IBM(32,63)
  56 #define EQE_CQ_TOKEN           EHCA_BMASK_IBM(32,63)
  57
  58 #define NEQE_COMPLETION_EVENT  EHCA_BMASK_IBM(1,1)
  59 #define NEQE_EVENT_CODE        EHCA_BMASK_IBM(2,7)
  60 #define NEQE_PORT_NUMBER       EHCA_BMASK_IBM(8,15)
  61 #define NEQE_PORT_AVAILABILITY EHCA_BMASK_IBM(16,16)
  62
  63 #define ERROR_DATA_LENGTH      EHCA_BMASK_IBM(52,63)
  64 #define ERROR_DATA_TYPE        EHCA_BMASK_IBM(0,7)
  65
  66 static void queue_comp_task(struct ehca_cq *__cq);
  67
  68 static struct ehca_comp_pool* pool;
  69 static struct notifier_block comp_pool_callback_nb;
  70
  71 static inline void comp_event_callback(struct ehca_cq *cq)
  72 {
  73         if (!cq->ib_cq.comp_handler)
  74                 return;
  75
  76         spin_lock(&cq->cb_lock);
  77         cq->ib_cq.comp_handler(&cq->ib_cq, cq->ib_cq.cq_context);
  78         spin_unlock(&cq->cb_lock);
  79
  80         return;
  81 }
  82
  83 static void print_error_data(struct ehca_shca * shca, void* data,
  84                              u64* rblock, int length)
  85 {
  86         u64 type = EHCA_BMASK_GET(ERROR_DATA_TYPE, rblock[2]);
  87         u64 resource = rblock[1];
  88
  89         switch (type) {
  90         case 0x1: /* Queue Pair */
  91         {
  92                 struct ehca_qp *qp = (struct ehca_qp*)data;
  93
  94                 /* only print error data if AER is set */
  95                 if (rblock[6] == 0)
  96                         return;
  97
  98                 ehca_err(&shca->ib_device,
  99                          "QP 0x%x (resource=%lx) has errors.",
 100                          qp->ib_qp.qp_num, resource);
 101                 break;
 102         }
 103         case 0x4: /* Completion Queue */
 104         {
 105                 struct ehca_cq *cq = (struct ehca_cq*)data;
 106
 107                 ehca_err(&shca->ib_device,
 108                          "CQ 0x%x (resource=%lx) has errors.",
 109                          cq->cq_number, resource);
 110                 break;
 111         }
 112         default:
 113                 ehca_err(&shca->ib_device,
 114                          "Unknown errror type: %lx on %s.",
 115                          type, shca->ib_device.name);
 116                 break;
 117         }
 118
 119         ehca_err(&shca->ib_device, "Error data is available: %lx.", resource);
 120         ehca_err(&shca->ib_device, "EHCA ----- error data begin "
 121                  "---------------------------------------------------");
 122         ehca_dmp(rblock, length, "resource=%lx", resource);
 123         ehca_err(&shca->ib_device, "EHCA ----- error data end "
 124                  "----------------------------------------------------");
 125
 126         return;
 127 }
 128
 129 int ehca_error_data(struct ehca_shca *shca, void *data,
 130                     u64 resource)
 131 {
 132
 133         unsigned long ret;
 134         u64 *rblock;
 135         unsigned long block_count;
 136
 137         rblock = ehca_alloc_fw_ctrlblock(GFP_ATOMIC);
 138         if (!rblock) {
 139                 ehca_err(&shca->ib_device, "Cannot allocate rblock memory.");
 140                 ret = -ENOMEM;
 141                 goto error_data1;
 142         }
 143
 144         /* rblock must be 4K aligned and should be 4K large */
 145         ret = hipz_h_error_data(shca->ipz_hca_handle,
 146                                 resource,
 147                                 rblock,
 148                                 &block_count);
 149
 150         if (ret == H_R_STATE)
 151                 ehca_err(&shca->ib_device,
 152                          "No error data is available: %lx.", resource);
 153         else if (ret == H_SUCCESS) {
 154                 int length;
 155
 156                 length = EHCA_BMASK_GET(ERROR_DATA_LENGTH, rblock[0]);
 157
 158                 if (length > EHCA_PAGESIZE)
 159                         length = EHCA_PAGESIZE;
 160
 161                 print_error_data(shca, data, rblock, length);
 162         } else
 163                 ehca_err(&shca->ib_device,
 164                          "Error data could not be fetched: %lx", resource);
 165
 166         ehca_free_fw_ctrlblock(rblock);
 167
 168 error_data1:
 169         return ret;
 170
 171 }
 172
 173 static void qp_event_callback(struct ehca_shca *shca,
 174                               u64 eqe,
 175                               enum ib_event_type event_type)
 176 {
 177         struct ib_event event;
 178         struct ehca_qp *qp;
 179         unsigned long flags;
 180         u32 token = EHCA_BMASK_GET(EQE_QP_TOKEN, eqe);
 181
 182         spin_lock_irqsave(&ehca_qp_idr_lock, flags);
 183         qp = idr_find(&ehca_qp_idr, token);
 184         spin_unlock_irqrestore(&ehca_qp_idr_lock, flags);
 185
 186
 187         if (!qp)
 188                 return;
 189
 190         ehca_error_data(shca, qp, qp->ipz_qp_handle.handle);
 191
 192         if (!qp->ib_qp.event_handler)
 193                 return;
 194
 195         event.device     = &shca->ib_device;
 196         event.event      = event_type;
 197         event.element.qp = &qp->ib_qp;
 198
 199         qp->ib_qp.event_handler(&event, qp->ib_qp.qp_context);
 200
 201         return;
 202 }
 203
 204 static void cq_event_callback(struct ehca_shca *shca,
 205                               u64 eqe)
 206 {
 207         struct ehca_cq *cq;
 208         unsigned long flags;
 209         u32 token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe);
 210
 211         spin_lock_irqsave(&ehca_cq_idr_lock, flags);
 212         cq = idr_find(&ehca_cq_idr, token);
 213         spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
 214
 215         if (!cq)
 216                 return;
 217
 218         ehca_error_data(shca, cq, cq->ipz_cq_handle.handle);
 219
 220         return;
 221 }
 222
 223 static void parse_identifier(struct ehca_shca *shca, u64 eqe)
 224 {
 225         u8 identifier = EHCA_BMASK_GET(EQE_EE_IDENTIFIER, eqe);
 226
 227         switch (identifier) {
 228         case 0x02: /* path migrated */
 229                 qp_event_callback(shca, eqe, IB_EVENT_PATH_MIG);
 230                 break;
 231         case 0x03: /* communication established */
 232                 qp_event_callback(shca, eqe, IB_EVENT_COMM_EST);
 233                 break;
 234         case 0x04: /* send queue drained */
 235                 qp_event_callback(shca, eqe, IB_EVENT_SQ_DRAINED);
 236                 break;
 237         case 0x05: /* QP error */
 238         case 0x06: /* QP error */
 239                 qp_event_callback(shca, eqe, IB_EVENT_QP_FATAL);
 240                 break;
 241         case 0x07: /* CQ error */
 242         case 0x08: /* CQ error */
 243                 cq_event_callback(shca, eqe);
 244                 break;
 245         case 0x09: /* MRMWPTE error */
 246                 ehca_err(&shca->ib_device, "MRMWPTE error.");
 247                 break;
 248         case 0x0A: /* port event */
 249                 ehca_err(&shca->ib_device, "Port event.");
 250                 break;
 251         case 0x0B: /* MR access error */
 252                 ehca_err(&shca->ib_device, "MR access error.");
 253                 break;
 254         case 0x0C: /* EQ error */
 255                 ehca_err(&shca->ib_device, "EQ error.");
 256                 break;
 257         case 0x0D: /* P/Q_Key mismatch */
 258                 ehca_err(&shca->ib_device, "P/Q_Key mismatch.");
 259                 break;
 260         case 0x10: /* sampling complete */
 261                 ehca_err(&shca->ib_device, "Sampling complete.");
 262                 break;
 263         case 0x11: /* unaffiliated access error */
 264                 ehca_err(&shca->ib_device, "Unaffiliated access error.");
 265                 break;
 266         case 0x12: /* path migrating error */
 267                 ehca_err(&shca->ib_device, "Path migration error.");
 268                 break;
 269         case 0x13: /* interface trace stopped */
 270                 ehca_err(&shca->ib_device, "Interface trace stopped.");
 271                 break;
 272         case 0x14: /* first error capture info available */
 273         default:
 274                 ehca_err(&shca->ib_device, "Unknown identifier: %x on %s.",
 275                          identifier, shca->ib_device.name);
 276                 break;
 277         }
 278
 279         return;
 280 }
 281
 282 static void parse_ec(struct ehca_shca *shca, u64 eqe)
 283 {
 284         struct ib_event event;
 285         u8 ec   = EHCA_BMASK_GET(NEQE_EVENT_CODE, eqe);
 286         u8 port = EHCA_BMASK_GET(NEQE_PORT_NUMBER, eqe);
 287
 288         switch (ec) {
 289         case 0x30: /* port availability change */
 290                 if (EHCA_BMASK_GET(NEQE_PORT_AVAILABILITY, eqe)) {
 291                         ehca_info(&shca->ib_device,
 292                                   "port %x is active.", port);
 293                         event.device = &shca->ib_device;
 294                         event.event = IB_EVENT_PORT_ACTIVE;
 295                         event.element.port_num = port;
 296                         shca->sport[port - 1].port_state = IB_PORT_ACTIVE;
 297                         ib_dispatch_event(&event);
 298                 } else {
 299                         ehca_info(&shca->ib_device,
 300                                   "port %x is inactive.", port);
 301                         event.device = &shca->ib_device;
 302                         event.event = IB_EVENT_PORT_ERR;
 303                         event.element.port_num = port;
 304                         shca->sport[port - 1].port_state = IB_PORT_DOWN;
 305                         ib_dispatch_event(&event);
 306                 }
 307                 break;
 308         case 0x31:
 309                 /* port configuration change
 310                  * disruptive change is caused by
 311                  * LID, PKEY or SM change
 312                  */
 313                 ehca_warn(&shca->ib_device,
 314                           "disruptive port %x configuration change", port);
 315
 316                 ehca_info(&shca->ib_device,
 317                           "port %x is inactive.", port);
 318                 event.device = &shca->ib_device;
 319                 event.event = IB_EVENT_PORT_ERR;
 320                 event.element.port_num = port;
 321                 shca->sport[port - 1].port_state = IB_PORT_DOWN;
 322                 ib_dispatch_event(&event);
 323
 324                 ehca_info(&shca->ib_device,
 325                           "port %x is active.", port);
 326                 event.device = &shca->ib_device;
 327                 event.event = IB_EVENT_PORT_ACTIVE;
 328                 event.element.port_num = port;
 329                 shca->sport[port - 1].port_state = IB_PORT_ACTIVE;
 330                 ib_dispatch_event(&event);
 331                 break;
 332         case 0x32: /* adapter malfunction */
 333                 ehca_err(&shca->ib_device, "Adapter malfunction.");
 334                 break;
 335         case 0x33:  /* trace stopped */
 336                 ehca_err(&shca->ib_device, "Traced stopped.");
 337                 break;
 338         default:
 339                 ehca_err(&shca->ib_device, "Unknown event code: %x on %s.",
 340                          ec, shca->ib_device.name);
 341                 break;
 342         }
 343
 344         return;
 345 }
 346
 347 static inline void reset_eq_pending(struct ehca_cq *cq)
 348 {
 349         u64 CQx_EP;
 350         struct h_galpa gal = cq->galpas.kernel;
 351
 352         hipz_galpa_store_cq(gal, cqx_ep, 0x0);
 353         CQx_EP = hipz_galpa_load(gal, CQTEMM_OFFSET(cqx_ep));
 354
 355         return;
 356 }
 357
 358 irqreturn_t ehca_interrupt_neq(int irq, void *dev_id)
 359 {
 360         struct ehca_shca *shca = (struct ehca_shca*)dev_id;
 361
 362         tasklet_hi_schedule(&shca->neq.interrupt_task);
 363
 364         return IRQ_HANDLED;
 365 }
 366
 367 void ehca_tasklet_neq(unsigned long data)
 368 {
 369         struct ehca_shca *shca = (struct ehca_shca*)data;
 370         struct ehca_eqe *eqe;
 371         u64 ret;
 372
 373         eqe = (struct ehca_eqe *)ehca_poll_eq(shca, &shca->neq);
 374
 375         while (eqe) {
 376                 if (!EHCA_BMASK_GET(NEQE_COMPLETION_EVENT, eqe->entry))
 377                         parse_ec(shca, eqe->entry);
 378
 379                 eqe = (struct ehca_eqe *)ehca_poll_eq(shca, &shca->neq);
 380         }
 381
 382         ret = hipz_h_reset_event(shca->ipz_hca_handle,
 383                                  shca->neq.ipz_eq_handle, 0xFFFFFFFFFFFFFFFFL);
 384
 385         if (ret != H_SUCCESS)
 386                 ehca_err(&shca->ib_device, "Can't clear notification events.");
 387
 388         return;
 389 }
 390
 391 irqreturn_t ehca_interrupt_eq(int irq, void *dev_id)
 392 {
 393         struct ehca_shca *shca = (struct ehca_shca*)dev_id;
 394
 395         tasklet_hi_schedule(&shca->eq.interrupt_task);
 396
 397         return IRQ_HANDLED;
 398 }
 399
 400
 401 static inline void process_eqe(struct ehca_shca *shca, struct ehca_eqe *eqe)
 402 {
 403         u64 eqe_value;
 404         u32 token;
 405         unsigned long flags;
 406         struct ehca_cq *cq;
 407         eqe_value = eqe->entry;
 408         ehca_dbg(&shca->ib_device, "eqe_value=%lx", eqe_value);
 409         if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
 410                 ehca_dbg(&shca->ib_device, "... completion event");
 411                 token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
 412                 spin_lock_irqsave(&ehca_cq_idr_lock, flags);
 413                 cq = idr_find(&ehca_cq_idr, token);
 414                 if (cq == NULL) {
 415                         spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
 416                         ehca_err(&shca->ib_device,
 417                                  "Invalid eqe for non-existing cq token=%x",
 418                                  token);
 419                         return;
 420                 }
 421                 reset_eq_pending(cq);
 422                 if (ehca_scaling_code) {
 423                         queue_comp_task(cq);
 424                         spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
 425                 } else {
 426                         spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
 427                         comp_event_callback(cq);
 428                 }
 429         } else {
 430                 ehca_dbg(&shca->ib_device,
 431                          "Got non completion event");
 432                 parse_identifier(shca, eqe_value);
 433         }
 434 }
 435
 436 void ehca_process_eq(struct ehca_shca *shca, int is_irq)
 437 {
 438         struct ehca_eq *eq = &shca->eq;
 439         struct ehca_eqe_cache_entry *eqe_cache = eq->eqe_cache;
 440         u64 eqe_value;
 441         unsigned long flags;
 442         int eqe_cnt, i;
 443         int eq_empty = 0;
 444
 445         spin_lock_irqsave(&eq->irq_spinlock, flags);
 446         if (is_irq) {
 447                 const int max_query_cnt = 100;
 448                 int query_cnt = 0;
 449                 int int_state = 1;
 450                 do {
 451                         int_state = hipz_h_query_int_state(
 452                                 shca->ipz_hca_handle, eq->ist);
 453                         query_cnt++;
 454                         iosync();
 455                 } while (int_state && query_cnt < max_query_cnt);
 456                 if (unlikely((query_cnt == max_query_cnt)))
 457                         ehca_dbg(&shca->ib_device, "int_state=%x query_cnt=%x",
 458                                  int_state, query_cnt);
 459         }
 460
 461         /* read out all eqes */
 462         eqe_cnt = 0;
 463         do {
 464                 u32 token;
 465                 eqe_cache[eqe_cnt].eqe =
 466                         (struct ehca_eqe *)ehca_poll_eq(shca, eq);
 467                 if (!eqe_cache[eqe_cnt].eqe)
 468                         break;
 469                 eqe_value = eqe_cache[eqe_cnt].eqe->entry;
 470                 if (EHCA_BMASK_GET(EQE_COMPLETION_EVENT, eqe_value)) {
 471                         token = EHCA_BMASK_GET(EQE_CQ_TOKEN, eqe_value);
 472                         spin_lock(&ehca_cq_idr_lock);
 473                         eqe_cache[eqe_cnt].cq = idr_find(&ehca_cq_idr, token);
 474                         if (!eqe_cache[eqe_cnt].cq) {
 475                                 spin_unlock(&ehca_cq_idr_lock);
 476                                 ehca_err(&shca->ib_device,
 477                                          "Invalid eqe for non-existing cq "
 478                                          "token=%x", token);
 479                                 continue;
 480                         }
 481                         spin_unlock(&ehca_cq_idr_lock);
 482                 } else
 483                         eqe_cache[eqe_cnt].cq = NULL;
 484                 eqe_cnt++;
 485         } while (eqe_cnt < EHCA_EQE_CACHE_SIZE);
 486         if (!eqe_cnt) {
 487                 if (is_irq)
 488                         ehca_dbg(&shca->ib_device,
 489                                  "No eqe found for irq event");
 490                 goto unlock_irq_spinlock;
 491         } else if (!is_irq)
 492                 ehca_dbg(&shca->ib_device, "deadman found %x eqe", eqe_cnt);
 493         if (unlikely(eqe_cnt == EHCA_EQE_CACHE_SIZE))
 494                 ehca_dbg(&shca->ib_device, "too many eqes for one irq event");
 495         /* enable irq for new packets */
 496         for (i = 0; i < eqe_cnt; i++) {
 497                 if (eq->eqe_cache[i].cq)
 498                         reset_eq_pending(eq->eqe_cache[i].cq);
 499         }
 500         /* check eq */
 501         spin_lock(&eq->spinlock);
 502         eq_empty = (!ipz_eqit_eq_peek_valid(&shca->eq.ipz_queue));
 503         spin_unlock(&eq->spinlock);
 504         /* call completion handler for cached eqes */
 505         for (i = 0; i < eqe_cnt; i++)
 506                 if (eq->eqe_cache[i].cq) {
 507                         if (ehca_scaling_code) {
 508                                 spin_lock(&ehca_cq_idr_lock);
 509                                 queue_comp_task(eq->eqe_cache[i].cq);
 510                                 spin_unlock(&ehca_cq_idr_lock);
 511                         } else
 512                                 comp_event_callback(eq->eqe_cache[i].cq);
 513                 } else {
 514                         ehca_dbg(&shca->ib_device, "Got non completion event");
 515                         parse_identifier(shca, eq->eqe_cache[i].eqe->entry);
 516                 }
 517         /* poll eq if not empty */
 518         if (eq_empty)
 519                 goto unlock_irq_spinlock;
 520         do {
 521                 struct ehca_eqe *eqe;
 522                 eqe = (struct ehca_eqe *)ehca_poll_eq(shca, &shca->eq);
 523                 if (!eqe)
 524                         break;
 525                 process_eqe(shca, eqe);
 526                 eqe_cnt++;
 527         } while (1);
 528
 529 unlock_irq_spinlock:
 530         spin_unlock_irqrestore(&eq->irq_spinlock, flags);
 531 }
 532
 533 void ehca_tasklet_eq(unsigned long data)
 534 {
 535         ehca_process_eq((struct ehca_shca*)data, 1);
 536 }
 537
 538 static inline int find_next_online_cpu(struct ehca_comp_pool* pool)
 539 {
 540         int cpu;
 541         unsigned long flags;
 542
 543         WARN_ON_ONCE(!in_interrupt());
 544         if (ehca_debug_level)
 545                 ehca_dmp(&cpu_online_map, sizeof(cpumask_t), "");
 546
 547         spin_lock_irqsave(&pool->last_cpu_lock, flags);
 548         cpu = next_cpu(pool->last_cpu, cpu_online_map);
 549         if (cpu == NR_CPUS)
 550                 cpu = first_cpu(cpu_online_map);
 551         pool->last_cpu = cpu;
 552         spin_unlock_irqrestore(&pool->last_cpu_lock, flags);
 553
 554         return cpu;
 555 }
 556
 557 static void __queue_comp_task(struct ehca_cq *__cq,
 558                               struct ehca_cpu_comp_task *cct)
 559 {
 560         unsigned long flags;
 561
 562         spin_lock_irqsave(&cct->task_lock, flags);
 563         spin_lock(&__cq->task_lock);
 564
 565         if (__cq->nr_callbacks == 0) {
 566                 __cq->nr_callbacks++;
 567                 list_add_tail(&__cq->entry, &cct->cq_list);
 568                 cct->cq_jobs++;
 569                 wake_up(&cct->wait_queue);
 570         }
 571         else
 572                 __cq->nr_callbacks++;
 573
 574         spin_unlock(&__cq->task_lock);
 575         spin_unlock_irqrestore(&cct->task_lock, flags);
 576 }
 577
 578 static void queue_comp_task(struct ehca_cq *__cq)
 579 {
 580         int cpu;
 581         int cpu_id;
 582         struct ehca_cpu_comp_task *cct;
 583
 584         cpu = get_cpu();
 585         cpu_id = find_next_online_cpu(pool);
 586         BUG_ON(!cpu_online(cpu_id));
 587
 588         cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu_id);
 589         BUG_ON(!cct);
 590
 591         if (cct->cq_jobs > 0) {
 592                 cpu_id = find_next_online_cpu(pool);
 593                 cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu_id);
 594                 BUG_ON(!cct);
 595         }
 596
 597         __queue_comp_task(__cq, cct);
 598 }
 599
 600 static void run_comp_task(struct ehca_cpu_comp_task* cct)
 601 {
 602         struct ehca_cq *cq;
 603         unsigned long flags;
 604
 605         spin_lock_irqsave(&cct->task_lock, flags);
 606
 607         while (!list_empty(&cct->cq_list)) {
 608                 cq = list_entry(cct->cq_list.next, struct ehca_cq, entry);
 609                 spin_unlock_irqrestore(&cct->task_lock, flags);
 610                 comp_event_callback(cq);
 611                 spin_lock_irqsave(&cct->task_lock, flags);
 612
 613                 spin_lock(&cq->task_lock);
 614                 cq->nr_callbacks--;
 615                 if (cq->nr_callbacks == 0) {
 616                         list_del_init(cct->cq_list.next);
 617                         cct->cq_jobs--;
 618                 }
 619                 spin_unlock(&cq->task_lock);
 620         }
 621
 622         spin_unlock_irqrestore(&cct->task_lock, flags);
 623 }
 624
 625 static int comp_task(void *__cct)
 626 {
 627         struct ehca_cpu_comp_task* cct = __cct;
 628         int cql_empty;
 629         DECLARE_WAITQUEUE(wait, current);
 630
 631         set_current_state(TASK_INTERRUPTIBLE);
 632         while(!kthread_should_stop()) {
 633                 add_wait_queue(&cct->wait_queue, &wait);
 634
 635                 spin_lock_irq(&cct->task_lock);
 636                 cql_empty = list_empty(&cct->cq_list);
 637                 spin_unlock_irq(&cct->task_lock);
 638                 if (cql_empty)
 639                         schedule();
 640                 else
 641                         __set_current_state(TASK_RUNNING);
 642
 643                 remove_wait_queue(&cct->wait_queue, &wait);
 644
 645                 spin_lock_irq(&cct->task_lock);
 646                 cql_empty = list_empty(&cct->cq_list);
 647                 spin_unlock_irq(&cct->task_lock);
 648                 if (!cql_empty)
 649                         run_comp_task(__cct);
 650
 651                 set_current_state(TASK_INTERRUPTIBLE);
 652         }
 653         __set_current_state(TASK_RUNNING);
 654
 655         return 0;
 656 }
 657
 658 static struct task_struct *create_comp_task(struct ehca_comp_pool *pool,
 659                                             int cpu)
 660 {
 661         struct ehca_cpu_comp_task *cct;
 662
 663         cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
 664         spin_lock_init(&cct->task_lock);
 665         INIT_LIST_HEAD(&cct->cq_list);
 666         init_waitqueue_head(&cct->wait_queue);
 667         cct->task = kthread_create(comp_task, cct, "ehca_comp/%d", cpu);
 668
 669         return cct->task;
 670 }
 671
 672 static void destroy_comp_task(struct ehca_comp_pool *pool,
 673                               int cpu)
 674 {
 675         struct ehca_cpu_comp_task *cct;
 676         struct task_struct *task;
 677         unsigned long flags_cct;
 678
 679         cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
 680
 681         spin_lock_irqsave(&cct->task_lock, flags_cct);
 682
 683         task = cct->task;
 684         cct->task = NULL;
 685         cct->cq_jobs = 0;
 686
 687         spin_unlock_irqrestore(&cct->task_lock, flags_cct);
 688
 689         if (task)
 690                 kthread_stop(task);
 691 }
 692
 693 static void take_over_work(struct ehca_comp_pool *pool,
 694                            int cpu)
 695 {
 696         struct ehca_cpu_comp_task *cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
 697         LIST_HEAD(list);
 698         struct ehca_cq *cq;
 699         unsigned long flags_cct;
 700
 701         spin_lock_irqsave(&cct->task_lock, flags_cct);
 702
 703         list_splice_init(&cct->cq_list, &list);
 704
 705         while(!list_empty(&list)) {
 706                 cq = list_entry(cct->cq_list.next, struct ehca_cq, entry);
 707
 708                 list_del(&cq->entry);
 709                 __queue_comp_task(cq, per_cpu_ptr(pool->cpu_comp_tasks,
 710                                                   smp_processor_id()));
 711         }
 712
 713         spin_unlock_irqrestore(&cct->task_lock, flags_cct);
 714
 715 }
 716
 717 static int comp_pool_callback(struct notifier_block *nfb,
 718                               unsigned long action,
 719                               void *hcpu)
 720 {
 721         unsigned int cpu = (unsigned long)hcpu;
 722         struct ehca_cpu_comp_task *cct;
 723
 724         switch (action) {
 725         case CPU_UP_PREPARE:
 726                 ehca_gen_dbg("CPU: %x (CPU_PREPARE)", cpu);
 727                 if(!create_comp_task(pool, cpu)) {
 728                         ehca_gen_err("Can't create comp_task for cpu: %x", cpu);
 729                         return NOTIFY_BAD;
 730                 }
 731                 break;
 732         case CPU_UP_CANCELED:
 733                 ehca_gen_dbg("CPU: %x (CPU_CANCELED)", cpu);
 734                 cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
 735                 kthread_bind(cct->task, any_online_cpu(cpu_online_map));
 736                 destroy_comp_task(pool, cpu);
 737                 break;
 738         case CPU_ONLINE:
 739                 ehca_gen_dbg("CPU: %x (CPU_ONLINE)", cpu);
 740                 cct = per_cpu_ptr(pool->cpu_comp_tasks, cpu);
 741                 kthread_bind(cct->task, cpu);
 742                 wake_up_process(cct->task);
 743                 break;
 744         case CPU_DOWN_PREPARE:
 745                 ehca_gen_dbg("CPU: %x (CPU_DOWN_PREPARE)", cpu);
 746                 break;
 747         case CPU_DOWN_FAILED:
 748                 ehca_gen_dbg("CPU: %x (CPU_DOWN_FAILED)", cpu);
 749                 break;
 750         case CPU_DEAD:
 751                 ehca_gen_dbg("CPU: %x (CPU_DEAD)", cpu);
 752                 destroy_comp_task(pool, cpu);
 753                 take_over_work(pool, cpu);
 754                 break;
 755         }
 756
 757         return NOTIFY_OK;
 758 }
 759
 760 int ehca_create_comp_pool(void)
 761 {
 762         int cpu;
 763         struct task_struct *task;
 764
 765         if (!ehca_scaling_code)
 766                 return 0;
 767
 768         pool = kzalloc(sizeof(struct ehca_comp_pool), GFP_KERNEL);
 769         if (pool == NULL)
 770                 return -ENOMEM;
 771
 772         spin_lock_init(&pool->last_cpu_lock);
 773         pool->last_cpu = any_online_cpu(cpu_online_map);
 774
 775         pool->cpu_comp_tasks = alloc_percpu(struct ehca_cpu_comp_task);
 776         if (pool->cpu_comp_tasks == NULL) {
 777                 kfree(pool);
 778                 return -EINVAL;
 779         }
 780
 781         for_each_online_cpu(cpu) {
 782                 task = create_comp_task(pool, cpu);
 783                 if (task) {
 784                         kthread_bind(task, cpu);
 785                         wake_up_process(task);
 786                 }
 787         }
 788
 789         comp_pool_callback_nb.notifier_call = comp_pool_callback;
 790         comp_pool_callback_nb.priority =0;
 791         register_cpu_notifier(&comp_pool_callback_nb);
 792
 793         printk(KERN_INFO "eHCA scaling code enabled\n");
 794
 795         return 0;
 796 }
 797
 798 void ehca_destroy_comp_pool(void)
 799 {
 800         int i;
 801
 802         if (!ehca_scaling_code)
 803                 return;
 804
 805         unregister_cpu_notifier(&comp_pool_callback_nb);
 806
 807         for (i = 0; i < NR_CPUS; i++) {
 808                 if (cpu_online(i))
 809                         destroy_comp_task(pool, i);
 810         }
 811         free_percpu(pool->cpu_comp_tasks);
 812         kfree(pool);
 813 }