fs/orangefs/orangefs-bufmap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * (C) 2001 Clemson University and The University of Chicago
   4  *
   5  * See COPYING in top-level directory.
   6  */
   7 #include "protocol.h"
   8 #include "orangefs-kernel.h"
   9 #include "orangefs-bufmap.h"
  10
  11 struct slot_map {
  12         int c;
  13         wait_queue_head_t q;
  14         int count;
  15         unsigned long *map;
  16 };
  17
  18 static struct slot_map rw_map = {
  19         .c = -1,
  20         .q = __WAIT_QUEUE_HEAD_INITIALIZER(rw_map.q)
  21 };
  22 static struct slot_map readdir_map = {
  23         .c = -1,
  24         .q = __WAIT_QUEUE_HEAD_INITIALIZER(readdir_map.q)
  25 };
  26
  27
  28 static void install(struct slot_map *m, int count, unsigned long *map)
  29 {
  30         spin_lock(&m->q.lock);
  31         m->c = m->count = count;
  32         m->map = map;
  33         wake_up_all_locked(&m->q);
  34         spin_unlock(&m->q.lock);
  35 }
  36
  37 static void mark_killed(struct slot_map *m)
  38 {
  39         spin_lock(&m->q.lock);
  40         m->c -= m->count + 1;
  41         spin_unlock(&m->q.lock);
  42 }
  43
  44 static void run_down(struct slot_map *m)
  45 {
  46         DEFINE_WAIT(wait);
  47         spin_lock(&m->q.lock);
  48         if (m->c != -1) {
  49                 for (;;) {
  50                         if (likely(list_empty(&wait.entry)))
  51                                 __add_wait_queue_entry_tail(&m->q, &wait);
  52                         set_current_state(TASK_UNINTERRUPTIBLE);
  53
  54                         if (m->c == -1)
  55                                 break;
  56
  57                         spin_unlock(&m->q.lock);
  58                         schedule();
  59                         spin_lock(&m->q.lock);
  60                 }
  61                 __remove_wait_queue(&m->q, &wait);
  62                 __set_current_state(TASK_RUNNING);
  63         }
  64         m->map = NULL;
  65         spin_unlock(&m->q.lock);
  66 }
  67
  68 static void put(struct slot_map *m, int slot)
  69 {
  70         int v;
  71         spin_lock(&m->q.lock);
  72         __clear_bit(slot, m->map);
  73         v = ++m->c;
  74         if (unlikely(v == 1))   /* no free slots -> one free slot */
  75                 wake_up_locked(&m->q);
  76         else if (unlikely(v == -1))     /* finished dying */
  77                 wake_up_all_locked(&m->q);
  78         spin_unlock(&m->q.lock);
  79 }
  80
  81 static int wait_for_free(struct slot_map *m)
  82 {
  83         long left = slot_timeout_secs * HZ;
  84         DEFINE_WAIT(wait);
  85
  86         do {
  87                 long n = left, t;
  88                 if (likely(list_empty(&wait.entry)))
  89                         __add_wait_queue_entry_tail_exclusive(&m->q, &wait);
  90                 set_current_state(TASK_INTERRUPTIBLE);
  91
  92                 if (m->c > 0)
  93                         break;
  94
  95                 if (m->c < 0) {
  96                         /* we are waiting for map to be installed */
  97                         /* it would better be there soon, or we go away */
  98                         if (n > ORANGEFS_BUFMAP_WAIT_TIMEOUT_SECS * HZ)
  99                                 n = ORANGEFS_BUFMAP_WAIT_TIMEOUT_SECS * HZ;
 100                 }
 101                 spin_unlock(&m->q.lock);
 102                 t = schedule_timeout(n);
 103                 spin_lock(&m->q.lock);
 104                 if (unlikely(!t) && n != left && m->c < 0)
 105                         left = t;
 106                 else
 107                         left = t + (left - n);
 108                 if (unlikely(signal_pending(current)))
 109                         left = -EINTR;
 110         } while (left > 0);
 111
 112         if (!list_empty(&wait.entry))
 113                 list_del(&wait.entry);
 114         else if (left <= 0 && waitqueue_active(&m->q))
 115                 __wake_up_locked_key(&m->q, TASK_INTERRUPTIBLE, NULL);
 116         __set_current_state(TASK_RUNNING);
 117
 118         if (likely(left > 0))
 119                 return 0;
 120
 121         return left < 0 ? -EINTR : -ETIMEDOUT;
 122 }
 123
 124 static int get(struct slot_map *m)
 125 {
 126         int res = 0;
 127         spin_lock(&m->q.lock);
 128         if (unlikely(m->c <= 0))
 129                 res = wait_for_free(m);
 130         if (likely(!res)) {
 131                 m->c--;
 132                 res = find_first_zero_bit(m->map, m->count);
 133                 __set_bit(res, m->map);
 134         }
 135         spin_unlock(&m->q.lock);
 136         return res;
 137 }
 138
 139 /* used to describe mapped buffers */
 140 struct orangefs_bufmap_desc {
 141         void *uaddr;                    /* user space address pointer */
 142         struct page **page_array;       /* array of mapped pages */
 143         int array_count;                /* size of above arrays */
 144         struct list_head list_link;
 145 };
 146
 147 static struct orangefs_bufmap {
 148         int desc_size;
 149         int desc_shift;
 150         int desc_count;
 151         int total_size;
 152         int page_count;
 153
 154         struct page **page_array;
 155         struct orangefs_bufmap_desc *desc_array;
 156
 157         /* array to track usage of buffer descriptors */
 158         unsigned long *buffer_index_array;
 159
 160         /* array to track usage of buffer descriptors for readdir */
 161 #define N DIV_ROUND_UP(ORANGEFS_READDIR_DEFAULT_DESC_COUNT, BITS_PER_LONG)
 162         unsigned long readdir_index_array[N];
 163 #undef N
 164 } *__orangefs_bufmap;
 165
 166 static DEFINE_SPINLOCK(orangefs_bufmap_lock);
 167
 168 static void
 169 orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap)
 170 {
 171         int i;
 172
 173         for (i = 0; i < bufmap->page_count; i++)
 174                 put_page(bufmap->page_array[i]);
 175 }
 176
 177 static void
 178 orangefs_bufmap_free(struct orangefs_bufmap *bufmap)
 179 {
 180         kfree(bufmap->page_array);
 181         kfree(bufmap->desc_array);
 182         kfree(bufmap->buffer_index_array);
 183         kfree(bufmap);
 184 }
 185
 186 /*
 187  * XXX: Can the size and shift change while the caller gives up the
 188  * XXX: lock between calling this and doing something useful?
 189  */
 190
 191 int orangefs_bufmap_size_query(void)
 192 {
 193         struct orangefs_bufmap *bufmap;
 194         int size = 0;
 195         spin_lock(&orangefs_bufmap_lock);
 196         bufmap = __orangefs_bufmap;
 197         if (bufmap)
 198                 size = bufmap->desc_size;
 199         spin_unlock(&orangefs_bufmap_lock);
 200         return size;
 201 }
 202
 203 int orangefs_bufmap_shift_query(void)
 204 {
 205         struct orangefs_bufmap *bufmap;
 206         int shift = 0;
 207         spin_lock(&orangefs_bufmap_lock);
 208         bufmap = __orangefs_bufmap;
 209         if (bufmap)
 210                 shift = bufmap->desc_shift;
 211         spin_unlock(&orangefs_bufmap_lock);
 212         return shift;
 213 }
 214
 215 static DECLARE_WAIT_QUEUE_HEAD(bufmap_waitq);
 216 static DECLARE_WAIT_QUEUE_HEAD(readdir_waitq);
 217
 218 /*
 219  * orangefs_get_bufmap_init
 220  *
 221  * If bufmap_init is 1, then the shared memory system, including the
 222  * buffer_index_array, is available.  Otherwise, it is not.
 223  *
 224  * returns the value of bufmap_init
 225  */
 226 int orangefs_get_bufmap_init(void)
 227 {
 228         return __orangefs_bufmap ? 1 : 0;
 229 }
 230
 231
 232 static struct orangefs_bufmap *
 233 orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc *user_desc)
 234 {
 235         struct orangefs_bufmap *bufmap;
 236
 237         bufmap = kzalloc(sizeof(*bufmap), GFP_KERNEL);
 238         if (!bufmap)
 239                 goto out;
 240
 241         bufmap->total_size = user_desc->total_size;
 242         bufmap->desc_count = user_desc->count;
 243         bufmap->desc_size = user_desc->size;
 244         bufmap->desc_shift = ilog2(bufmap->desc_size);
 245
 246         bufmap->buffer_index_array =
 247                 kzalloc(DIV_ROUND_UP(bufmap->desc_count, BITS_PER_LONG), GFP_KERNEL);
 248         if (!bufmap->buffer_index_array)
 249                 goto out_free_bufmap;
 250
 251         bufmap->desc_array =
 252                 kcalloc(bufmap->desc_count, sizeof(struct orangefs_bufmap_desc),
 253                         GFP_KERNEL);
 254         if (!bufmap->desc_array)
 255                 goto out_free_index_array;
 256
 257         bufmap->page_count = bufmap->total_size / PAGE_SIZE;
 258
 259         /* allocate storage to track our page mappings */
 260         bufmap->page_array =
 261                 kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
 262         if (!bufmap->page_array)
 263                 goto out_free_desc_array;
 264
 265         return bufmap;
 266
 267 out_free_desc_array:
 268         kfree(bufmap->desc_array);
 269 out_free_index_array:
 270         kfree(bufmap->buffer_index_array);
 271 out_free_bufmap:
 272         kfree(bufmap);
 273 out:
 274         return NULL;
 275 }
 276
 277 static int
 278 orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
 279                 struct ORANGEFS_dev_map_desc *user_desc)
 280 {
 281         int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
 282         int offset = 0, ret, i;
 283
 284         /* map the pages */
 285         ret = get_user_pages_fast((unsigned long)user_desc->ptr,
 286                              bufmap->page_count, 1, bufmap->page_array);
 287
 288         if (ret < 0)
 289                 return ret;
 290
 291         if (ret != bufmap->page_count) {
 292                 gossip_err("orangefs error: asked for %d pages, only got %d.\n",
 293                                 bufmap->page_count, ret);
 294
 295                 for (i = 0; i < ret; i++) {
 296                         SetPageError(bufmap->page_array[i]);
 297                         put_page(bufmap->page_array[i]);
 298                 }
 299                 return -ENOMEM;
 300         }
 301
 302         /*
 303          * ideally we want to get kernel space pointers for each page, but
 304          * we can't kmap that many pages at once if highmem is being used.
 305          * so instead, we just kmap/kunmap the page address each time the
 306          * kaddr is needed.
 307          */
 308         for (i = 0; i < bufmap->page_count; i++)
 309                 flush_dcache_page(bufmap->page_array[i]);
 310
 311         /* build a list of available descriptors */
 312         for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
 313                 bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
 314                 bufmap->desc_array[i].array_count = pages_per_desc;
 315                 bufmap->desc_array[i].uaddr =
 316                     (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
 317                 offset += pages_per_desc;
 318         }
 319
 320         return 0;
 321 }
 322
 323 /*
 324  * orangefs_bufmap_initialize()
 325  *
 326  * initializes the mapped buffer interface
 327  *
 328  * returns 0 on success, -errno on failure
 329  */
 330 int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
 331 {
 332         struct orangefs_bufmap *bufmap;
 333         int ret = -EINVAL;
 334
 335         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 336                      "orangefs_bufmap_initialize: called (ptr ("
 337                      "%p) sz (%d) cnt(%d).\n",
 338                      user_desc->ptr,
 339                      user_desc->size,
 340                      user_desc->count);
 341
 342         if (user_desc->total_size < 0 ||
 343             user_desc->size < 0 ||
 344             user_desc->count < 0)
 345                 goto out;
 346
 347         /*
 348          * sanity check alignment and size of buffer that caller wants to
 349          * work with
 350          */
 351         if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
 352             (unsigned long)user_desc->ptr) {
 353                 gossip_err("orangefs error: memory alignment (front). %p\n",
 354                            user_desc->ptr);
 355                 goto out;
 356         }
 357
 358         if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
 359             != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
 360                 gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
 361                            user_desc->ptr,
 362                            user_desc->total_size);
 363                 goto out;
 364         }
 365
 366         if (user_desc->total_size != (user_desc->size * user_desc->count)) {
 367                 gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
 368                            user_desc->total_size,
 369                            user_desc->size,
 370                            user_desc->count);
 371                 goto out;
 372         }
 373
 374         if ((user_desc->size % PAGE_SIZE) != 0) {
 375                 gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
 376                            user_desc->size);
 377                 goto out;
 378         }
 379
 380         ret = -ENOMEM;
 381         bufmap = orangefs_bufmap_alloc(user_desc);
 382         if (!bufmap)
 383                 goto out;
 384
 385         ret = orangefs_bufmap_map(bufmap, user_desc);
 386         if (ret)
 387                 goto out_free_bufmap;
 388
 389
 390         spin_lock(&orangefs_bufmap_lock);
 391         if (__orangefs_bufmap) {
 392                 spin_unlock(&orangefs_bufmap_lock);
 393                 gossip_err("orangefs: error: bufmap already initialized.\n");
 394                 ret = -EINVAL;
 395                 goto out_unmap_bufmap;
 396         }
 397         __orangefs_bufmap = bufmap;
 398         install(&rw_map,
 399                 bufmap->desc_count,
 400                 bufmap->buffer_index_array);
 401         install(&readdir_map,
 402                 ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
 403                 bufmap->readdir_index_array);
 404         spin_unlock(&orangefs_bufmap_lock);
 405
 406         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 407                      "orangefs_bufmap_initialize: exiting normally\n");
 408         return 0;
 409
 410 out_unmap_bufmap:
 411         orangefs_bufmap_unmap(bufmap);
 412 out_free_bufmap:
 413         orangefs_bufmap_free(bufmap);
 414 out:
 415         return ret;
 416 }
 417
 418 /*
 419  * orangefs_bufmap_finalize()
 420  *
 421  * shuts down the mapped buffer interface and releases any resources
 422  * associated with it
 423  *
 424  * no return value
 425  */
 426 void orangefs_bufmap_finalize(void)
 427 {
 428         struct orangefs_bufmap *bufmap = __orangefs_bufmap;
 429         if (!bufmap)
 430                 return;
 431         gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
 432         mark_killed(&rw_map);
 433         mark_killed(&readdir_map);
 434         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 435                      "orangefs_bufmap_finalize: exiting normally\n");
 436 }
 437
 438 void orangefs_bufmap_run_down(void)
 439 {
 440         struct orangefs_bufmap *bufmap = __orangefs_bufmap;
 441         if (!bufmap)
 442                 return;
 443         run_down(&rw_map);
 444         run_down(&readdir_map);
 445         spin_lock(&orangefs_bufmap_lock);
 446         __orangefs_bufmap = NULL;
 447         spin_unlock(&orangefs_bufmap_lock);
 448         orangefs_bufmap_unmap(bufmap);
 449         orangefs_bufmap_free(bufmap);
 450 }
 451
 452 /*
 453  * orangefs_bufmap_get()
 454  *
 455  * gets a free mapped buffer descriptor, will sleep until one becomes
 456  * available if necessary
 457  *
 458  * returns slot on success, -errno on failure
 459  */
 460 int orangefs_bufmap_get(void)
 461 {
 462         return get(&rw_map);
 463 }
 464
 465 /*
 466  * orangefs_bufmap_put()
 467  *
 468  * returns a mapped buffer descriptor to the collection
 469  *
 470  * no return value
 471  */
 472 void orangefs_bufmap_put(int buffer_index)
 473 {
 474         put(&rw_map, buffer_index);
 475 }
 476
 477 /*
 478  * orangefs_readdir_index_get()
 479  *
 480  * gets a free descriptor, will sleep until one becomes
 481  * available if necessary.
 482  * Although the readdir buffers are not mapped into kernel space
 483  * we could do that at a later point of time. Regardless, these
 484  * indices are used by the client-core.
 485  *
 486  * returns slot on success, -errno on failure
 487  */
 488 int orangefs_readdir_index_get(void)
 489 {
 490         return get(&readdir_map);
 491 }
 492
 493 void orangefs_readdir_index_put(int buffer_index)
 494 {
 495         put(&readdir_map, buffer_index);
 496 }
 497
 498 /*
 499  * we've been handed an iovec, we need to copy it to
 500  * the shared memory descriptor at "buffer_index".
 501  */
 502 int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
 503                                 int buffer_index,
 504                                 size_t size)
 505 {
 506         struct orangefs_bufmap_desc *to;
 507         int i;
 508
 509         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 510                      "%s: buffer_index:%d: size:%zu:\n",
 511                      __func__, buffer_index, size);
 512
 513         to = &__orangefs_bufmap->desc_array[buffer_index];
 514         for (i = 0; size; i++) {
 515                 struct page *page = to->page_array[i];
 516                 size_t n = size;
 517                 if (n > PAGE_SIZE)
 518                         n = PAGE_SIZE;
 519                 if (copy_page_from_iter(page, 0, n, iter) != n)
 520                         return -EFAULT;
 521                 size -= n;
 522         }
 523         return 0;
 524 }
 525
 526 /*
 527  * we've been handed an iovec, we need to fill it from
 528  * the shared memory descriptor at "buffer_index".
 529  */
 530 int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
 531                                     int buffer_index,
 532                                     size_t size)
 533 {
 534         struct orangefs_bufmap_desc *from;
 535         int i;
 536
 537         from = &__orangefs_bufmap->desc_array[buffer_index];
 538         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 539                      "%s: buffer_index:%d: size:%zu:\n",
 540                      __func__, buffer_index, size);
 541
 542
 543         for (i = 0; size; i++) {
 544                 struct page *page = from->page_array[i];
 545                 size_t n = size;
 546                 if (n > PAGE_SIZE)
 547                         n = PAGE_SIZE;
 548                 n = copy_page_to_iter(page, 0, n, iter);
 549                 if (!n)
 550                         return -EFAULT;
 551                 size -= n;
 552         }
 553         return 0;
 554 }