fs/orangefs/pvfs2-bufmap.c

   1 /*
   2  * (C) 2001 Clemson University and The University of Chicago
   3  *
   4  * See COPYING in top-level directory.
   5  */
   6 #include "protocol.h"
   7 #include "pvfs2-kernel.h"
   8 #include "pvfs2-bufmap.h"
   9
  10 DECLARE_WAIT_QUEUE_HEAD(pvfs2_bufmap_init_waitq);
  11
  12 static struct pvfs2_bufmap {
  13         atomic_t refcnt;
  14
  15         int desc_size;
  16         int desc_shift;
  17         int desc_count;
  18         int total_size;
  19         int page_count;
  20
  21         struct page **page_array;
  22         struct pvfs_bufmap_desc *desc_array;
  23
  24         /* array to track usage of buffer descriptors */
  25         int *buffer_index_array;
  26         spinlock_t buffer_index_lock;
  27
  28         /* array to track usage of buffer descriptors for readdir */
  29         int readdir_index_array[PVFS2_READDIR_DEFAULT_DESC_COUNT];
  30         spinlock_t readdir_index_lock;
  31 } *__pvfs2_bufmap;
  32
  33 static DEFINE_SPINLOCK(pvfs2_bufmap_lock);
  34
  35 static void
  36 pvfs2_bufmap_unmap(struct pvfs2_bufmap *bufmap)
  37 {
  38         int i;
  39
  40         for (i = 0; i < bufmap->page_count; i++)
  41                 page_cache_release(bufmap->page_array[i]);
  42 }
  43
  44 static void
  45 pvfs2_bufmap_free(struct pvfs2_bufmap *bufmap)
  46 {
  47         kfree(bufmap->page_array);
  48         kfree(bufmap->desc_array);
  49         kfree(bufmap->buffer_index_array);
  50         kfree(bufmap);
  51 }
  52
  53 struct pvfs2_bufmap *pvfs2_bufmap_ref(void)
  54 {
  55         struct pvfs2_bufmap *bufmap = NULL;
  56
  57         spin_lock(&pvfs2_bufmap_lock);
  58         if (__pvfs2_bufmap) {
  59                 bufmap = __pvfs2_bufmap;
  60                 atomic_inc(&bufmap->refcnt);
  61         }
  62         spin_unlock(&pvfs2_bufmap_lock);
  63         return bufmap;
  64 }
  65
  66 void pvfs2_bufmap_unref(struct pvfs2_bufmap *bufmap)
  67 {
  68         if (atomic_dec_and_lock(&bufmap->refcnt, &pvfs2_bufmap_lock)) {
  69                 __pvfs2_bufmap = NULL;
  70                 spin_unlock(&pvfs2_bufmap_lock);
  71
  72                 pvfs2_bufmap_unmap(bufmap);
  73                 pvfs2_bufmap_free(bufmap);
  74         }
  75 }
  76
  77 inline int pvfs_bufmap_size_query(void)
  78 {
  79         struct pvfs2_bufmap *bufmap = pvfs2_bufmap_ref();
  80         int size = bufmap ? bufmap->desc_size : 0;
  81
  82         pvfs2_bufmap_unref(bufmap);
  83         return size;
  84 }
  85
  86 inline int pvfs_bufmap_shift_query(void)
  87 {
  88         struct pvfs2_bufmap *bufmap = pvfs2_bufmap_ref();
  89         int shift = bufmap ? bufmap->desc_shift : 0;
  90
  91         pvfs2_bufmap_unref(bufmap);
  92         return shift;
  93 }
  94
  95 static DECLARE_WAIT_QUEUE_HEAD(bufmap_waitq);
  96 static DECLARE_WAIT_QUEUE_HEAD(readdir_waitq);
  97
  98 /*
  99  * get_bufmap_init
 100  *
 101  * If bufmap_init is 1, then the shared memory system, including the
 102  * buffer_index_array, is available.  Otherwise, it is not.
 103  *
 104  * returns the value of bufmap_init
 105  */
 106 int get_bufmap_init(void)
 107 {
 108         return __pvfs2_bufmap ? 1 : 0;
 109 }
 110
 111
 112 static struct pvfs2_bufmap *
 113 pvfs2_bufmap_alloc(struct PVFS_dev_map_desc *user_desc)
 114 {
 115         struct pvfs2_bufmap *bufmap;
 116
 117         bufmap = kzalloc(sizeof(*bufmap), GFP_KERNEL);
 118         if (!bufmap)
 119                 goto out;
 120
 121         atomic_set(&bufmap->refcnt, 1);
 122         bufmap->total_size = user_desc->total_size;
 123         bufmap->desc_count = user_desc->count;
 124         bufmap->desc_size = user_desc->size;
 125         bufmap->desc_shift = ilog2(bufmap->desc_size);
 126
 127         spin_lock_init(&bufmap->buffer_index_lock);
 128         bufmap->buffer_index_array =
 129                 kcalloc(bufmap->desc_count, sizeof(int), GFP_KERNEL);
 130         if (!bufmap->buffer_index_array) {
 131                 gossip_err("pvfs2: could not allocate %d buffer indices\n",
 132                                 bufmap->desc_count);
 133                 goto out_free_bufmap;
 134         }
 135         spin_lock_init(&bufmap->readdir_index_lock);
 136
 137         bufmap->desc_array =
 138                 kcalloc(bufmap->desc_count, sizeof(struct pvfs_bufmap_desc),
 139                         GFP_KERNEL);
 140         if (!bufmap->desc_array) {
 141                 gossip_err("pvfs2: could not allocate %d descriptors\n",
 142                                 bufmap->desc_count);
 143                 goto out_free_index_array;
 144         }
 145
 146         bufmap->page_count = bufmap->total_size / PAGE_SIZE;
 147
 148         /* allocate storage to track our page mappings */
 149         bufmap->page_array =
 150                 kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
 151         if (!bufmap->page_array)
 152                 goto out_free_desc_array;
 153
 154         return bufmap;
 155
 156 out_free_desc_array:
 157         kfree(bufmap->desc_array);
 158 out_free_index_array:
 159         kfree(bufmap->buffer_index_array);
 160 out_free_bufmap:
 161         kfree(bufmap);
 162 out:
 163         return NULL;
 164 }
 165
 166 static int
 167 pvfs2_bufmap_map(struct pvfs2_bufmap *bufmap,
 168                 struct PVFS_dev_map_desc *user_desc)
 169 {
 170         int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
 171         int offset = 0, ret, i;
 172
 173         /* map the pages */
 174         down_write(&current->mm->mmap_sem);
 175         ret = get_user_pages(current,
 176                              current->mm,
 177                              (unsigned long)user_desc->ptr,
 178                              bufmap->page_count,
 179                              1,
 180                              0,
 181                              bufmap->page_array,
 182                              NULL);
 183         up_write(&current->mm->mmap_sem);
 184
 185         if (ret < 0)
 186                 return ret;
 187
 188         if (ret != bufmap->page_count) {
 189                 gossip_err("pvfs2 error: asked for %d pages, only got %d.\n",
 190                                 bufmap->page_count, ret);
 191
 192                 for (i = 0; i < ret; i++) {
 193                         SetPageError(bufmap->page_array[i]);
 194                         page_cache_release(bufmap->page_array[i]);
 195                 }
 196                 return -ENOMEM;
 197         }
 198
 199         /*
 200          * ideally we want to get kernel space pointers for each page, but
 201          * we can't kmap that many pages at once if highmem is being used.
 202          * so instead, we just kmap/kunmap the page address each time the
 203          * kaddr is needed.
 204          */
 205         for (i = 0; i < bufmap->page_count; i++)
 206                 flush_dcache_page(bufmap->page_array[i]);
 207
 208         /* build a list of available descriptors */
 209         for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
 210                 bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
 211                 bufmap->desc_array[i].array_count = pages_per_desc;
 212                 bufmap->desc_array[i].uaddr =
 213                     (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
 214                 offset += pages_per_desc;
 215         }
 216
 217         return 0;
 218 }
 219
 220 /*
 221  * pvfs_bufmap_initialize()
 222  *
 223  * initializes the mapped buffer interface
 224  *
 225  * returns 0 on success, -errno on failure
 226  */
 227 int pvfs_bufmap_initialize(struct PVFS_dev_map_desc *user_desc)
 228 {
 229         struct pvfs2_bufmap *bufmap;
 230         int ret = -EINVAL;
 231
 232         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 233                      "pvfs_bufmap_initialize: called (ptr ("
 234                      "%p) sz (%d) cnt(%d).\n",
 235                      user_desc->ptr,
 236                      user_desc->size,
 237                      user_desc->count);
 238
 239         /*
 240          * sanity check alignment and size of buffer that caller wants to
 241          * work with
 242          */
 243         if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
 244             (unsigned long)user_desc->ptr) {
 245                 gossip_err("pvfs2 error: memory alignment (front). %p\n",
 246                            user_desc->ptr);
 247                 goto out;
 248         }
 249
 250         if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
 251             != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
 252                 gossip_err("pvfs2 error: memory alignment (back).(%p + %d)\n",
 253                            user_desc->ptr,
 254                            user_desc->total_size);
 255                 goto out;
 256         }
 257
 258         if (user_desc->total_size != (user_desc->size * user_desc->count)) {
 259                 gossip_err("pvfs2 error: user provided an oddly sized buffer: (%d, %d, %d)\n",
 260                            user_desc->total_size,
 261                            user_desc->size,
 262                            user_desc->count);
 263                 goto out;
 264         }
 265
 266         if ((user_desc->size % PAGE_SIZE) != 0) {
 267                 gossip_err("pvfs2 error: bufmap size not page size divisible (%d).\n",
 268                            user_desc->size);
 269                 goto out;
 270         }
 271
 272         ret = -ENOMEM;
 273         bufmap = pvfs2_bufmap_alloc(user_desc);
 274         if (!bufmap)
 275                 goto out;
 276
 277         ret = pvfs2_bufmap_map(bufmap, user_desc);
 278         if (ret)
 279                 goto out_free_bufmap;
 280
 281
 282         spin_lock(&pvfs2_bufmap_lock);
 283         if (__pvfs2_bufmap) {
 284                 spin_unlock(&pvfs2_bufmap_lock);
 285                 gossip_err("pvfs2: error: bufmap already initialized.\n");
 286                 ret = -EALREADY;
 287                 goto out_unmap_bufmap;
 288         }
 289         __pvfs2_bufmap = bufmap;
 290         spin_unlock(&pvfs2_bufmap_lock);
 291
 292         /*
 293          * If there are operations in pvfs2_bufmap_init_waitq, wake them up.
 294          * This scenario occurs when the client-core is restarted and I/O
 295          * requests in the in-progress or waiting tables are restarted.  I/O
 296          * requests cannot be restarted until the shared memory system is
 297          * completely re-initialized, so we put the I/O requests in this
 298          * waitq until initialization has completed.  NOTE:  the I/O requests
 299          * are also on a timer, so they don't wait forever just in case the
 300          * client-core doesn't come back up.
 301          */
 302         wake_up_interruptible(&pvfs2_bufmap_init_waitq);
 303
 304         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 305                      "pvfs_bufmap_initialize: exiting normally\n");
 306         return 0;
 307
 308 out_unmap_bufmap:
 309         pvfs2_bufmap_unmap(bufmap);
 310 out_free_bufmap:
 311         pvfs2_bufmap_free(bufmap);
 312 out:
 313         return ret;
 314 }
 315
 316 /*
 317  * pvfs_bufmap_finalize()
 318  *
 319  * shuts down the mapped buffer interface and releases any resources
 320  * associated with it
 321  *
 322  * no return value
 323  */
 324 void pvfs_bufmap_finalize(void)
 325 {
 326         gossip_debug(GOSSIP_BUFMAP_DEBUG, "pvfs2_bufmap_finalize: called\n");
 327         BUG_ON(!__pvfs2_bufmap);
 328         pvfs2_bufmap_unref(__pvfs2_bufmap);
 329         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 330                      "pvfs2_bufmap_finalize: exiting normally\n");
 331 }
 332
 333 struct slot_args {
 334         int slot_count;
 335         int *slot_array;
 336         spinlock_t *slot_lock;
 337         wait_queue_head_t *slot_wq;
 338 };
 339
 340 static int wait_for_a_slot(struct slot_args *slargs, int *buffer_index)
 341 {
 342         int ret = -1;
 343         int i = 0;
 344         DECLARE_WAITQUEUE(my_wait, current);
 345
 346
 347         add_wait_queue_exclusive(slargs->slot_wq, &my_wait);
 348
 349         while (1) {
 350                 set_current_state(TASK_INTERRUPTIBLE);
 351
 352                 /*
 353                  * check for available desc, slot_lock is the appropriate
 354                  * index_lock
 355                  */
 356                 spin_lock(slargs->slot_lock);
 357                 for (i = 0; i < slargs->slot_count; i++)
 358                         if (slargs->slot_array[i] == 0) {
 359                                 slargs->slot_array[i] = 1;
 360                                 *buffer_index = i;
 361                                 ret = 0;
 362                                 break;
 363                         }
 364                 spin_unlock(slargs->slot_lock);
 365
 366                 /* if we acquired a buffer, then break out of while */
 367                 if (ret == 0)
 368                         break;
 369
 370                 if (!signal_pending(current)) {
 371                         int timeout =
 372                             MSECS_TO_JIFFIES(1000 * slot_timeout_secs);
 373                         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 374                                      "[BUFMAP]: waiting %d "
 375                                      "seconds for a slot\n",
 376                                      slot_timeout_secs);
 377                         if (!schedule_timeout(timeout)) {
 378                                 gossip_debug(GOSSIP_BUFMAP_DEBUG,
 379                                              "*** wait_for_a_slot timed out\n");
 380                                 ret = -ETIMEDOUT;
 381                                 break;
 382                         }
 383                         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 384                           "[BUFMAP]: woken up by a slot becoming available.\n");
 385                         continue;
 386                 }
 387
 388                 gossip_debug(GOSSIP_BUFMAP_DEBUG, "pvfs2: %s interrupted.\n",
 389                              __func__);
 390                 ret = -EINTR;
 391                 break;
 392         }
 393
 394         set_current_state(TASK_RUNNING);
 395         remove_wait_queue(slargs->slot_wq, &my_wait);
 396         return ret;
 397 }
 398
 399 static void put_back_slot(struct slot_args *slargs, int buffer_index)
 400 {
 401         /* slot_lock is the appropriate index_lock */
 402         spin_lock(slargs->slot_lock);
 403         if (buffer_index < 0 || buffer_index >= slargs->slot_count) {
 404                 spin_unlock(slargs->slot_lock);
 405                 return;
 406         }
 407
 408         /* put the desc back on the queue */
 409         slargs->slot_array[buffer_index] = 0;
 410         spin_unlock(slargs->slot_lock);
 411
 412         /* wake up anyone who may be sleeping on the queue */
 413         wake_up_interruptible(slargs->slot_wq);
 414 }
 415
 416 /*
 417  * pvfs_bufmap_get()
 418  *
 419  * gets a free mapped buffer descriptor, will sleep until one becomes
 420  * available if necessary
 421  *
 422  * returns 0 on success, -errno on failure
 423  */
 424 int pvfs_bufmap_get(struct pvfs2_bufmap **mapp, int *buffer_index)
 425 {
 426         struct pvfs2_bufmap *bufmap = pvfs2_bufmap_ref();
 427         struct slot_args slargs;
 428         int ret;
 429
 430         if (!bufmap) {
 431                 gossip_err("pvfs2: please confirm that pvfs2-client daemon is running.\n");
 432                 return -EIO;
 433         }
 434
 435         slargs.slot_count = bufmap->desc_count;
 436         slargs.slot_array = bufmap->buffer_index_array;
 437         slargs.slot_lock = &bufmap->buffer_index_lock;
 438         slargs.slot_wq = &bufmap_waitq;
 439         ret = wait_for_a_slot(&slargs, buffer_index);
 440         if (ret)
 441                 pvfs2_bufmap_unref(bufmap);
 442         *mapp = bufmap;
 443         return ret;
 444 }
 445
 446 /*
 447  * pvfs_bufmap_put()
 448  *
 449  * returns a mapped buffer descriptor to the collection
 450  *
 451  * no return value
 452  */
 453 void pvfs_bufmap_put(struct pvfs2_bufmap *bufmap, int buffer_index)
 454 {
 455         struct slot_args slargs;
 456
 457         slargs.slot_count = bufmap->desc_count;
 458         slargs.slot_array = bufmap->buffer_index_array;
 459         slargs.slot_lock = &bufmap->buffer_index_lock;
 460         slargs.slot_wq = &bufmap_waitq;
 461         put_back_slot(&slargs, buffer_index);
 462         pvfs2_bufmap_unref(bufmap);
 463 }
 464
 465 /*
 466  * readdir_index_get()
 467  *
 468  * gets a free descriptor, will sleep until one becomes
 469  * available if necessary.
 470  * Although the readdir buffers are not mapped into kernel space
 471  * we could do that at a later point of time. Regardless, these
 472  * indices are used by the client-core.
 473  *
 474  * returns 0 on success, -errno on failure
 475  */
 476 int readdir_index_get(struct pvfs2_bufmap **mapp, int *buffer_index)
 477 {
 478         struct pvfs2_bufmap *bufmap = pvfs2_bufmap_ref();
 479         struct slot_args slargs;
 480         int ret;
 481
 482         if (!bufmap) {
 483                 gossip_err("pvfs2: please confirm that pvfs2-client daemon is running.\n");
 484                 return -EIO;
 485         }
 486
 487         slargs.slot_count = PVFS2_READDIR_DEFAULT_DESC_COUNT;
 488         slargs.slot_array = bufmap->readdir_index_array;
 489         slargs.slot_lock = &bufmap->readdir_index_lock;
 490         slargs.slot_wq = &readdir_waitq;
 491         ret = wait_for_a_slot(&slargs, buffer_index);
 492         if (ret)
 493                 pvfs2_bufmap_unref(bufmap);
 494         *mapp = bufmap;
 495         return ret;
 496 }
 497
 498 void readdir_index_put(struct pvfs2_bufmap *bufmap, int buffer_index)
 499 {
 500         struct slot_args slargs;
 501
 502         slargs.slot_count = PVFS2_READDIR_DEFAULT_DESC_COUNT;
 503         slargs.slot_array = bufmap->readdir_index_array;
 504         slargs.slot_lock = &bufmap->readdir_index_lock;
 505         slargs.slot_wq = &readdir_waitq;
 506         put_back_slot(&slargs, buffer_index);
 507         pvfs2_bufmap_unref(bufmap);
 508 }
 509
 510 int pvfs_bufmap_copy_from_iovec(struct pvfs2_bufmap *bufmap,
 511                                 struct iov_iter *iter,
 512                                 int buffer_index,
 513                                 size_t size)
 514 {
 515         struct pvfs_bufmap_desc *to;
 516         struct page *page;
 517         size_t copied;
 518         int i;
 519
 520         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 521                      "%s: buffer_index:%d: size:%lu:\n",
 522                      __func__, buffer_index, size);
 523
 524         to = &bufmap->desc_array[buffer_index];
 525
 526         for (i = 0; size; i++) {
 527                 page = to->page_array[i];
 528                 copied = copy_page_from_iter(page, 0, PAGE_SIZE, iter);
 529                 size -= copied;
 530                 if ((copied == 0) && (size))
 531                         break;
 532         }
 533
 534         return size ? -EFAULT : 0;
 535
 536 }
 537
 538 /*
 539  * Iterate through the array of pages containing the bytes from
 540  * a file being read.
 541  *
 542  */
 543 int pvfs_bufmap_copy_to_iovec(struct pvfs2_bufmap *bufmap,
 544                                     struct iov_iter *iter,
 545                                     int buffer_index)
 546 {
 547         struct pvfs_bufmap_desc *from;
 548         struct page *page;
 549         int i;
 550         size_t written;
 551
 552         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 553                      "%s: buffer_index:%d: iov_iter_count(iter):%lu:\n",
 554                      __func__, buffer_index, iov_iter_count(iter));
 555
 556         from = &bufmap->desc_array[buffer_index];
 557
 558         for (i = 0; iov_iter_count(iter); i++) {
 559                 page = from->page_array[i];
 560                 written = copy_page_to_iter(page, 0, PAGE_SIZE, iter);
 561                 if ((written == 0) && (iov_iter_count(iter)))
 562                         break;
 563         }
 564
 565         return iov_iter_count(iter) ? -EFAULT : 0;
 566 }