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 (v > 0)
  75                 wake_up_locked(&m->q);
  76         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 __user *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         bitmap_free(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 static struct orangefs_bufmap *
 219 orangefs_bufmap_alloc(struct ORANGEFS_dev_map_desc *user_desc)
 220 {
 221         struct orangefs_bufmap *bufmap;
 222
 223         bufmap = kzalloc(sizeof(*bufmap), GFP_KERNEL);
 224         if (!bufmap)
 225                 goto out;
 226
 227         bufmap->total_size = user_desc->total_size;
 228         bufmap->desc_count = user_desc->count;
 229         bufmap->desc_size = user_desc->size;
 230         bufmap->desc_shift = ilog2(bufmap->desc_size);
 231
 232         bufmap->buffer_index_array = bitmap_zalloc(bufmap->desc_count, GFP_KERNEL);
 233         if (!bufmap->buffer_index_array)
 234                 goto out_free_bufmap;
 235
 236         bufmap->desc_array =
 237                 kcalloc(bufmap->desc_count, sizeof(struct orangefs_bufmap_desc),
 238                         GFP_KERNEL);
 239         if (!bufmap->desc_array)
 240                 goto out_free_index_array;
 241
 242         bufmap->page_count = bufmap->total_size / PAGE_SIZE;
 243
 244         /* allocate storage to track our page mappings */
 245         bufmap->page_array =
 246                 kcalloc(bufmap->page_count, sizeof(struct page *), GFP_KERNEL);
 247         if (!bufmap->page_array)
 248                 goto out_free_desc_array;
 249
 250         return bufmap;
 251
 252 out_free_desc_array:
 253         kfree(bufmap->desc_array);
 254 out_free_index_array:
 255         bitmap_free(bufmap->buffer_index_array);
 256 out_free_bufmap:
 257         kfree(bufmap);
 258 out:
 259         return NULL;
 260 }
 261
 262 static int
 263 orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
 264                 struct ORANGEFS_dev_map_desc *user_desc)
 265 {
 266         int pages_per_desc = bufmap->desc_size / PAGE_SIZE;
 267         int offset = 0, ret, i;
 268
 269         /* map the pages */
 270         ret = get_user_pages_fast((unsigned long)user_desc->ptr,
 271                              bufmap->page_count, 1, bufmap->page_array);
 272
 273         if (ret < 0)
 274                 return ret;
 275
 276         if (ret != bufmap->page_count) {
 277                 gossip_err("orangefs error: asked for %d pages, only got %d.\n",
 278                                 bufmap->page_count, ret);
 279
 280                 for (i = 0; i < ret; i++) {
 281                         SetPageError(bufmap->page_array[i]);
 282                         put_page(bufmap->page_array[i]);
 283                 }
 284                 return -ENOMEM;
 285         }
 286
 287         /*
 288          * ideally we want to get kernel space pointers for each page, but
 289          * we can't kmap that many pages at once if highmem is being used.
 290          * so instead, we just kmap/kunmap the page address each time the
 291          * kaddr is needed.
 292          */
 293         for (i = 0; i < bufmap->page_count; i++)
 294                 flush_dcache_page(bufmap->page_array[i]);
 295
 296         /* build a list of available descriptors */
 297         for (offset = 0, i = 0; i < bufmap->desc_count; i++) {
 298                 bufmap->desc_array[i].page_array = &bufmap->page_array[offset];
 299                 bufmap->desc_array[i].array_count = pages_per_desc;
 300                 bufmap->desc_array[i].uaddr =
 301                     (user_desc->ptr + (i * pages_per_desc * PAGE_SIZE));
 302                 offset += pages_per_desc;
 303         }
 304
 305         return 0;
 306 }
 307
 308 /*
 309  * orangefs_bufmap_initialize()
 310  *
 311  * initializes the mapped buffer interface
 312  *
 313  * returns 0 on success, -errno on failure
 314  */
 315 int orangefs_bufmap_initialize(struct ORANGEFS_dev_map_desc *user_desc)
 316 {
 317         struct orangefs_bufmap *bufmap;
 318         int ret = -EINVAL;
 319
 320         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 321                      "orangefs_bufmap_initialize: called (ptr ("
 322                      "%p) sz (%d) cnt(%d).\n",
 323                      user_desc->ptr,
 324                      user_desc->size,
 325                      user_desc->count);
 326
 327         if (user_desc->total_size < 0 ||
 328             user_desc->size < 0 ||
 329             user_desc->count < 0)
 330                 goto out;
 331
 332         /*
 333          * sanity check alignment and size of buffer that caller wants to
 334          * work with
 335          */
 336         if (PAGE_ALIGN((unsigned long)user_desc->ptr) !=
 337             (unsigned long)user_desc->ptr) {
 338                 gossip_err("orangefs error: memory alignment (front). %p\n",
 339                            user_desc->ptr);
 340                 goto out;
 341         }
 342
 343         if (PAGE_ALIGN(((unsigned long)user_desc->ptr + user_desc->total_size))
 344             != (unsigned long)(user_desc->ptr + user_desc->total_size)) {
 345                 gossip_err("orangefs error: memory alignment (back).(%p + %d)\n",
 346                            user_desc->ptr,
 347                            user_desc->total_size);
 348                 goto out;
 349         }
 350
 351         if (user_desc->total_size != (user_desc->size * user_desc->count)) {
 352                 gossip_err("orangefs error: user provided an oddly sized buffer: (%d, %d, %d)\n",
 353                            user_desc->total_size,
 354                            user_desc->size,
 355                            user_desc->count);
 356                 goto out;
 357         }
 358
 359         if ((user_desc->size % PAGE_SIZE) != 0) {
 360                 gossip_err("orangefs error: bufmap size not page size divisible (%d).\n",
 361                            user_desc->size);
 362                 goto out;
 363         }
 364
 365         ret = -ENOMEM;
 366         bufmap = orangefs_bufmap_alloc(user_desc);
 367         if (!bufmap)
 368                 goto out;
 369
 370         ret = orangefs_bufmap_map(bufmap, user_desc);
 371         if (ret)
 372                 goto out_free_bufmap;
 373
 374
 375         spin_lock(&orangefs_bufmap_lock);
 376         if (__orangefs_bufmap) {
 377                 spin_unlock(&orangefs_bufmap_lock);
 378                 gossip_err("orangefs: error: bufmap already initialized.\n");
 379                 ret = -EINVAL;
 380                 goto out_unmap_bufmap;
 381         }
 382         __orangefs_bufmap = bufmap;
 383         install(&rw_map,
 384                 bufmap->desc_count,
 385                 bufmap->buffer_index_array);
 386         install(&readdir_map,
 387                 ORANGEFS_READDIR_DEFAULT_DESC_COUNT,
 388                 bufmap->readdir_index_array);
 389         spin_unlock(&orangefs_bufmap_lock);
 390
 391         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 392                      "orangefs_bufmap_initialize: exiting normally\n");
 393         return 0;
 394
 395 out_unmap_bufmap:
 396         orangefs_bufmap_unmap(bufmap);
 397 out_free_bufmap:
 398         orangefs_bufmap_free(bufmap);
 399 out:
 400         return ret;
 401 }
 402
 403 /*
 404  * orangefs_bufmap_finalize()
 405  *
 406  * shuts down the mapped buffer interface and releases any resources
 407  * associated with it
 408  *
 409  * no return value
 410  */
 411 void orangefs_bufmap_finalize(void)
 412 {
 413         struct orangefs_bufmap *bufmap = __orangefs_bufmap;
 414         if (!bufmap)
 415                 return;
 416         gossip_debug(GOSSIP_BUFMAP_DEBUG, "orangefs_bufmap_finalize: called\n");
 417         mark_killed(&rw_map);
 418         mark_killed(&readdir_map);
 419         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 420                      "orangefs_bufmap_finalize: exiting normally\n");
 421 }
 422
 423 void orangefs_bufmap_run_down(void)
 424 {
 425         struct orangefs_bufmap *bufmap = __orangefs_bufmap;
 426         if (!bufmap)
 427                 return;
 428         run_down(&rw_map);
 429         run_down(&readdir_map);
 430         spin_lock(&orangefs_bufmap_lock);
 431         __orangefs_bufmap = NULL;
 432         spin_unlock(&orangefs_bufmap_lock);
 433         orangefs_bufmap_unmap(bufmap);
 434         orangefs_bufmap_free(bufmap);
 435 }
 436
 437 /*
 438  * orangefs_bufmap_get()
 439  *
 440  * gets a free mapped buffer descriptor, will sleep until one becomes
 441  * available if necessary
 442  *
 443  * returns slot on success, -errno on failure
 444  */
 445 int orangefs_bufmap_get(void)
 446 {
 447         return get(&rw_map);
 448 }
 449
 450 /*
 451  * orangefs_bufmap_put()
 452  *
 453  * returns a mapped buffer descriptor to the collection
 454  *
 455  * no return value
 456  */
 457 void orangefs_bufmap_put(int buffer_index)
 458 {
 459         put(&rw_map, buffer_index);
 460 }
 461
 462 /*
 463  * orangefs_readdir_index_get()
 464  *
 465  * gets a free descriptor, will sleep until one becomes
 466  * available if necessary.
 467  * Although the readdir buffers are not mapped into kernel space
 468  * we could do that at a later point of time. Regardless, these
 469  * indices are used by the client-core.
 470  *
 471  * returns slot on success, -errno on failure
 472  */
 473 int orangefs_readdir_index_get(void)
 474 {
 475         return get(&readdir_map);
 476 }
 477
 478 void orangefs_readdir_index_put(int buffer_index)
 479 {
 480         put(&readdir_map, buffer_index);
 481 }
 482
 483 /*
 484  * we've been handed an iovec, we need to copy it to
 485  * the shared memory descriptor at "buffer_index".
 486  */
 487 int orangefs_bufmap_copy_from_iovec(struct iov_iter *iter,
 488                                 int buffer_index,
 489                                 size_t size)
 490 {
 491         struct orangefs_bufmap_desc *to;
 492         int i;
 493
 494         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 495                      "%s: buffer_index:%d: size:%zu:\n",
 496                      __func__, buffer_index, size);
 497
 498         to = &__orangefs_bufmap->desc_array[buffer_index];
 499         for (i = 0; size; i++) {
 500                 struct page *page = to->page_array[i];
 501                 size_t n = size;
 502                 if (n > PAGE_SIZE)
 503                         n = PAGE_SIZE;
 504                 if (copy_page_from_iter(page, 0, n, iter) != n)
 505                         return -EFAULT;
 506                 size -= n;
 507         }
 508         return 0;
 509 }
 510
 511 /*
 512  * we've been handed an iovec, we need to fill it from
 513  * the shared memory descriptor at "buffer_index".
 514  */
 515 int orangefs_bufmap_copy_to_iovec(struct iov_iter *iter,
 516                                     int buffer_index,
 517                                     size_t size)
 518 {
 519         struct orangefs_bufmap_desc *from;
 520         int i;
 521
 522         from = &__orangefs_bufmap->desc_array[buffer_index];
 523         gossip_debug(GOSSIP_BUFMAP_DEBUG,
 524                      "%s: buffer_index:%d: size:%zu:\n",
 525                      __func__, buffer_index, size);
 526
 527
 528         for (i = 0; size; i++) {
 529                 struct page *page = from->page_array[i];
 530                 size_t n = size;
 531                 if (n > PAGE_SIZE)
 532                         n = PAGE_SIZE;
 533                 n = copy_page_to_iter(page, 0, n, iter);
 534                 if (!n)
 535                         return -EFAULT;
 536                 size -= n;
 537         }
 538         return 0;
 539 }