buffer/buffer_queue.c

   1 /*
   2  *  SWAP Buffer Module
   3  *  modules/buffer/buffer_queue.c
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  *
  19  * Copyright (C) Samsung Electronics, 2013
  20  *
  21  * 2013  Alexander Aksenov <a.aksenov@samsung.com>: SWAP Buffer implement
  22  *
  23  */
  24
  25 /* SWAP buffer queues implementation */
  26
  27 /* For all memory allocation/deallocation operations, except buffer memory
  28  * allocation/deallocation should be used
  29  *  memory_allocation(size_t memory_size)
  30  *  memory_free(void *ptr)
  31  * defines.
  32  * For subbuffer allocation/deallocation operations should be used
  33  *  buffer_allocation(size_t subbuffer_size)
  34  *  buffer_free(void *ptr, size_t subbuffer_size)
  35  * To get buffer pointer for any usage, EXCEPT ALLOCATION AND DEALLOCATION
  36  * use the following define:
  37  *  buffer_pointer(void *ptr_to_buffer_element_of_swap_buffer_structure)
  38  * DO NOT USE SUBBUFFER PTR IN STRUCT SWAP_BUFFER WITHOUT THIS DEFINE!
  39  * It will be ok for user space, but fail in kernel space.
  40  *
  41  * See space_dep_types_and_def.h for details */
  42
  43
  44
  45 #include "buffer_queue.h"
  46 #include "swap_buffer_to_buffer_queue.h"
  47 #include "swap_buffer_errors.h"
  48
  49 /* Queue structure. Consist of pointers to the first and the last elements of
  50  * queue. */
  51 struct queue {
  52         struct swap_subbuffer *start_ptr;
  53         struct swap_subbuffer *end_ptr;
  54         struct sync_t queue_sync;
  55 };
  56
  57 /* Write queue */
  58 struct queue write_queue = {
  59         .start_ptr = NULL,
  60         .end_ptr = NULL,
  61         .queue_sync = {
  62                 .flags = 0x0
  63         }
  64 };
  65
  66 /* Read queue */
  67 struct queue read_queue = {
  68         .start_ptr = NULL,
  69         .end_ptr = NULL,
  70         .queue_sync = {
  71                 .flags = 0x0
  72         }
  73 };
  74
  75 /* Pointers array. Points to busy buffers */
  76 static struct swap_subbuffer **queue_busy = NULL;
  77
  78 /* Store last busy element */
  79 static unsigned int queue_busy_last_element;
  80
  81 /* Subbuffers count */
  82 static unsigned int queue_subbuffer_count = 0;
  83
  84 /* One subbuffer size */
  85 static size_t queue_subbuffer_size = 0;
  86
  87 /* Busy list sync */
  88 static struct sync_t buffer_busy_sync = {
  89         .flags = 0x0
  90 };
  91
  92 /* Memory pages count in one subbuffer */
  93 static int pages_order_in_subbuffer = 0;
  94
  95
  96 int buffer_queue_allocation(size_t subbuffer_size,
  97                             unsigned int subbuffers_count)
  98 {
  99         unsigned int i = 0;
 100         unsigned int j = 0;
 101         unsigned int allocated_buffers = 0;
 102         unsigned int allocated_structs = 0;
 103         struct swap_subbuffer *clean_tmp_struct;
 104         int result;
 105
 106         /* Static varibles initialization */
 107         queue_subbuffer_size = subbuffer_size;
 108         queue_subbuffer_count = subbuffers_count;
 109         queue_busy_last_element = 0;
 110
 111         /* Set variable pages_in_subbuffer. It is used for allocation and
 112          * deallocation memory pages and its value is returned from
 113          * swap_buffer_get() and contains page count in one subbuffer.
 114          * All this useful only in kernel space. In userspace it is dummy.*/
 115         set_pages_order_in_subbuffer(queue_subbuffer_size);
 116         /* Sync primitives initialization */
 117         sync_init(&read_queue.queue_sync);
 118         sync_init(&write_queue.queue_sync);
 119         sync_init(&buffer_busy_sync);
 120
 121         /* Memory allocation for queue_busy */
 122         queue_busy = memory_allocation(sizeof(&queue_busy) * queue_subbuffer_count);
 123
 124         if (!queue_busy) {
 125                 result = -E_SB_NO_MEM_QUEUE_BUSY;
 126                 goto buffer_allocation_error_ret;
 127         }
 128
 129         /* Memory allocation for swap_subbuffer structures */
 130
 131         /* Allocation for first structure. */
 132         write_queue.start_ptr = memory_allocation(sizeof(&write_queue.start_ptr));
 133
 134         if (!write_queue.start_ptr) {
 135                 result = -E_SB_NO_MEM_BUFFER_STRUCT;
 136                 goto buffer_allocation_queue_busy_free;
 137         }
 138         allocated_structs++;
 139
 140
 141         write_queue.end_ptr = write_queue.start_ptr;
 142
 143         write_queue.end_ptr->next_in_queue = NULL;
 144         write_queue.end_ptr->full_buffer_part = 0;
 145         write_queue.end_ptr->data_buffer = buffer_allocation(queue_subbuffer_size);
 146         if (!write_queue.end_ptr->data_buffer) {
 147                 print_err("Cannot allocate memory for buffer 1\n");
 148                 result = -E_SB_NO_MEM_DATA_BUFFER;
 149                 goto buffer_allocation_error_free;
 150         }
 151         allocated_buffers++;
 152
 153         print_msg(" Buffer allocated = 0x%x\n", (unsigned long)write_queue.end_ptr->data_buffer);
 154
 155         sync_init(&write_queue.end_ptr->buffer_sync);
 156
 157         /* Buffer initialization */
 158         memset(buffer_address(write_queue.end_ptr->data_buffer), 0, queue_subbuffer_size);
 159
 160         /* Allocation for other structures. */
 161         for (i = 1; i < queue_subbuffer_count; i++) {
 162                 write_queue.end_ptr->next_in_queue =
 163                     memory_allocation(sizeof(write_queue.end_ptr->next_in_queue));
 164                 if (!write_queue.end_ptr->next_in_queue) {
 165                         result = -E_SB_NO_MEM_BUFFER_STRUCT;
 166                         goto buffer_allocation_error_free;
 167                 }
 168                 allocated_structs++;
 169
 170                 /* Now next write_queue.end_ptr is next */
 171                 write_queue.end_ptr = write_queue.end_ptr->next_in_queue;
 172
 173                 write_queue.end_ptr->next_in_queue = NULL;
 174                 write_queue.end_ptr->full_buffer_part = 0;
 175                 write_queue.end_ptr->data_buffer =
 176                         buffer_allocation(queue_subbuffer_size);
 177                 if (!write_queue.end_ptr->data_buffer) {
 178                         result = -E_SB_NO_MEM_DATA_BUFFER;
 179                         goto buffer_allocation_error_free;
 180                 }
 181                 allocated_buffers++;
 182
 183                 print_msg(" Buffer allocated = 0x%x, pages_order = %d\n",
 184                           (unsigned long)buffer_address(write_queue.end_ptr->data_buffer),
 185                           pages_order_in_subbuffer);
 186
 187                 sync_init(&write_queue.end_ptr->buffer_sync);
 188
 189                 /* Buffer initialization */
 190                 memset(buffer_address(write_queue.end_ptr->data_buffer), 0,
 191                        queue_subbuffer_size);
 192         }
 193
 194         return E_SB_SUCCESS;
 195
 196         /* In case of errors, this code is called */
 197         /* Free all previously allocated memory */
 198 buffer_allocation_error_free:
 199         clean_tmp_struct = write_queue.start_ptr;
 200
 201         for (j = 0; j < allocated_structs; j++) {
 202                 clean_tmp_struct = write_queue.start_ptr;
 203                 if (allocated_buffers) {
 204                         buffer_free(clean_tmp_struct->data_buffer, queue_subbuffer_size);
 205                         allocated_buffers--;
 206                 }
 207                 if (write_queue.start_ptr != write_queue.end_ptr)
 208                         write_queue.start_ptr = write_queue.start_ptr->next_in_queue;
 209                 memory_free(clean_tmp_struct);
 210         }
 211         write_queue.end_ptr = NULL;
 212         write_queue.start_ptr = NULL;
 213
 214 buffer_allocation_queue_busy_free:
 215         memory_free(queue_busy);
 216         queue_busy = NULL;
 217
 218 buffer_allocation_error_ret:
 219         return result;
 220 }
 221
 222 void buffer_queue_free(void)
 223 {
 224         struct swap_subbuffer *tmp = NULL;
 225
 226         //TODO Lock read list semaphore to prevent getting subbuffer from read list
 227         /* Set all write buffers to read list */
 228         set_all_to_read_list();
 229
 230         /* Free buffers and structures memory that are in read list */
 231         while (read_queue.start_ptr) {
 232                 tmp = read_queue.start_ptr;
 233                 read_queue.start_ptr = read_queue.start_ptr->next_in_queue;
 234                 buffer_free(tmp->data_buffer, queue_subbuffer_size);
 235                 print_msg(" Buffer free = 0x%x\n", (unsigned long)
 236                            buffer_address(tmp->data_buffer));
 237                 memory_free(tmp);
 238         }
 239
 240         /* Free busy_list */
 241         memory_free(queue_busy);
 242         queue_busy = NULL;
 243
 244         queue_subbuffer_size = 0;
 245         queue_subbuffer_count = 0;
 246         read_queue.start_ptr = NULL;
 247         read_queue.end_ptr = NULL;
 248         write_queue.start_ptr = NULL;
 249         write_queue.end_ptr = NULL;
 250 }
 251
 252 static unsigned int is_buffer_enough(struct swap_subbuffer *subbuffer,
 253                                      size_t size)
 254 {
 255         /* XXX Think about checking full_buffer_part for correctness
 256          * (<queue_subbuffer_size). It should be true, but if isn't (due to sources
 257          * chaning, etc.) this function should be true! */
 258         return ((queue_subbuffer_size-subbuffer->full_buffer_part) >= size) ? 1 : 0;
 259 }
 260
 261 /* Get first subbuffer from read list */
 262 struct swap_subbuffer *get_from_read_list(void)
 263 {
 264         struct swap_subbuffer *result = NULL;
 265
 266         /* Lock read sync primitive */
 267         sync_lock(&read_queue.queue_sync);
 268
 269         if (read_queue.start_ptr == NULL) {
 270                 result = NULL;
 271                 goto get_from_read_list_unlock;
 272         }
 273
 274         result = read_queue.start_ptr;
 275
 276         /* If this is the last readable buffer, read_queue.start_ptr next time will
 277          * points to NULL and that case is handled in the beginning of function
 278          */
 279         if (read_queue.start_ptr == read_queue.end_ptr) {
 280                 read_queue.end_ptr = NULL;
 281         }
 282         read_queue.start_ptr = read_queue.start_ptr->next_in_queue;
 283
 284 get_from_read_list_unlock:
 285         /* Unlock read sync primitive */
 286         sync_unlock(&read_queue.queue_sync);
 287
 288         return result;
 289 }
 290
 291 /* Add subbuffer to read list */
 292 void add_to_read_list(struct swap_subbuffer *subbuffer)
 293 {
 294
 295         /* Lock read sync primitive */
 296         sync_lock(&read_queue.queue_sync);
 297
 298         if (!read_queue.start_ptr)
 299                 read_queue.start_ptr = subbuffer;
 300
 301         if (read_queue.end_ptr) {
 302                 read_queue.end_ptr->next_in_queue = subbuffer;
 303
 304                 read_queue.end_ptr = read_queue.end_ptr->next_in_queue;
 305         } else {
 306                 read_queue.end_ptr = subbuffer;
 307         }
 308         read_queue.end_ptr->next_in_queue = NULL;
 309
 310         /* Unlock read sync primitive */
 311         sync_unlock(&read_queue.queue_sync);
 312 }
 313
 314 /* Call add to read list and callback function from driver module */
 315 int add_to_read_list_with_callback(struct swap_subbuffer *subbuffer)
 316 {
 317         int result = 0;
 318
 319         add_to_read_list(subbuffer);
 320         // TODO Handle ret value
 321         result = swap_buffer_callback(subbuffer);
 322
 323         return result;
 324 }
 325
 326 /* Get first writable subbuffer from write list */
 327 struct swap_subbuffer *get_from_write_list(size_t size, void **ptr_to_write)
 328 {
 329         struct swap_subbuffer *result = NULL;
 330
 331         /* Callbacks are called at the end of the function to prevent deadlocks */
 332         struct queue callback_queue = {
 333                 .start_ptr = NULL,
 334                 .end_ptr = NULL,
 335                 .queue_sync = {
 336                         .flags = 0x0
 337                 }
 338         };
 339         struct swap_subbuffer *tmp_buffer = NULL;
 340
 341         /* Init pointer */
 342         *ptr_to_write = NULL;
 343
 344         /* Lock write list sync primitive */
 345         sync_lock(&write_queue.queue_sync);
 346
 347         while (write_queue.start_ptr) {
 348                 /* If start points to NULL => list is empty => exit */
 349                 if (!write_queue.start_ptr) {
 350                         result = NULL;
 351                         goto get_from_write_list_unlock;
 352                 }
 353
 354                 /* We're found subbuffer */
 355                 if (is_buffer_enough(write_queue.start_ptr, size)) {
 356
 357                         result = write_queue.start_ptr;
 358                         *ptr_to_write = (void *)((unsigned long)
 359                                                  (buffer_address(result->data_buffer)) +
 360                                                  result->full_buffer_part);
 361
 362                         /* Add data size to full_buffer_part. Very important to do it in
 363                          * write_queue.queue_sync spinlock */
 364                         write_queue.start_ptr->full_buffer_part += size;
 365
 366                         /* Lock rw sync. Should be unlocked in swap_buffer_write() */
 367                         sync_lock(&result->buffer_sync);
 368                         break;
 369                 /* This subbuffer is not enough => it goes to read list */
 370                 } else {
 371                         result = write_queue.start_ptr;
 372
 373                         /* If we reached end of the list */
 374                         if (write_queue.start_ptr == write_queue.end_ptr) {
 375                                 write_queue.end_ptr = NULL;
 376                         }
 377
 378                         /* Move start write pointer */
 379                         write_queue.start_ptr = write_queue.start_ptr->next_in_queue;
 380
 381                         /* Add to callback list */
 382                         if (!callback_queue.start_ptr)
 383                                 callback_queue.start_ptr = result;
 384
 385                         if (callback_queue.end_ptr)
 386                                 callback_queue.end_ptr->next_in_queue = result;
 387                         callback_queue.end_ptr = result;
 388                         callback_queue.end_ptr->next_in_queue = NULL;
 389                         result = NULL;
 390                 }
 391         }
 392
 393 get_from_write_list_unlock:
 394         /* Unlock write list sync primitive */
 395         sync_unlock(&write_queue.queue_sync);
 396
 397         /* Adding buffers to read list and calling callbacks */
 398         for (tmp_buffer = NULL; callback_queue.start_ptr; ) {
 399                 if (callback_queue.start_ptr == callback_queue.end_ptr)
 400                         callback_queue.end_ptr = NULL;
 401
 402                 tmp_buffer = callback_queue.start_ptr;
 403                 callback_queue.start_ptr = callback_queue.start_ptr->next_in_queue;
 404
 405                 add_to_read_list_with_callback(tmp_buffer);
 406         }
 407
 408         return result;
 409 }
 410
 411 /* Add subbuffer to write list */
 412 void add_to_write_list(struct swap_subbuffer *subbuffer)
 413 {
 414         sync_lock(&write_queue.queue_sync);
 415
 416         /* Reinitialize */
 417         // TODO Useless memset
 418 //      memset(buffer_address(subbuffer->data_buffer), 0, queue_subbuffer_size);
 419         subbuffer->full_buffer_part = 0;
 420
 421         if (!write_queue.start_ptr)
 422                 write_queue.start_ptr = subbuffer;
 423
 424         if (write_queue.end_ptr) {
 425                 write_queue.end_ptr->next_in_queue = subbuffer;
 426                 write_queue.end_ptr = write_queue.end_ptr->next_in_queue;
 427         } else {
 428                 write_queue.end_ptr = subbuffer;
 429         }
 430         write_queue.end_ptr->next_in_queue = NULL;
 431
 432         sync_unlock(&write_queue.queue_sync);
 433 }
 434
 435 /* Add subbuffer to busy list when it is read from out of the buffer */
 436 void add_to_busy_list(struct swap_subbuffer *subbuffer)
 437 {
 438         /* Lock busy sync primitive */
 439         sync_lock(&buffer_busy_sync);
 440
 441         subbuffer->next_in_queue = NULL;
 442         queue_busy[queue_busy_last_element] = subbuffer;
 443         queue_busy_last_element += 1;
 444
 445         /* Unlock busy sync primitive */
 446         sync_unlock(&buffer_busy_sync);
 447 }
 448
 449 /* Remove subbuffer from busy list when it is released */
 450 int remove_from_busy_list(struct swap_subbuffer *subbuffer)
 451 {
 452         int result = -E_SB_NO_SUBBUFFER_IN_BUSY; // For sanitization
 453         int i;
 454
 455         /* Lock busy list sync primitive */
 456         sync_lock(&buffer_busy_sync);
 457
 458         /* Sanitization and removing */
 459         for (i = 0; i < queue_busy_last_element; i++) {
 460                 if (queue_busy[i] == subbuffer) {
 461                         /* Last element goes here and length is down 1 */
 462                         queue_busy[i] = queue_busy[queue_busy_last_element - 1];
 463                         queue_busy_last_element -= 1;
 464                         result = E_SB_SUCCESS;
 465                         break;
 466                 }
 467         }
 468
 469         /* Unlock busy list sync primitive */
 470         sync_unlock(&buffer_busy_sync);
 471
 472         return result;
 473 }
 474
 475 /* Get subbuffers count in read list */
 476 /* XXX Think about locks */
 477 int get_full_buffers_count(void)
 478 {
 479         int result = 0;
 480         struct swap_subbuffer *buffer = read_queue.start_ptr;
 481
 482         while (buffer && buffer->full_buffer_part) {
 483                 result += 1;
 484                 buffer = buffer->next_in_queue;
 485         }
 486
 487         return result;
 488 }
 489
 490 /* Set all subbuffers in write list to read list */
 491 void set_all_to_read_list(void)
 492 {
 493         struct swap_subbuffer *buffer = write_queue.start_ptr;
 494
 495         /* Locking write sync primitive */
 496         sync_lock(&write_queue.queue_sync);
 497
 498         while (write_queue.start_ptr &&
 499                write_queue.start_ptr->full_buffer_part) {
 500                 /* Waiting till semaphore should be posted */
 501
 502 // TODO To think: It's not bad as it is, but maybe it would be better locking
 503 // semaphore while changing its list? (Not bad now, cause buffer should have
 504 // already been stopped).
 505
 506                 sync_lock(&buffer->buffer_sync);
 507
 508                 sync_unlock(&buffer->buffer_sync);
 509
 510                 buffer = write_queue.start_ptr;
 511
 512                 /* If we reached end of the list */
 513                 if (write_queue.start_ptr == write_queue.end_ptr) {
 514                         write_queue.end_ptr = NULL;
 515                 }
 516                 write_queue.start_ptr = write_queue.start_ptr->next_in_queue;
 517
 518                 add_to_read_list(buffer);
 519         }
 520
 521         /* Unlocking write primitive */
 522         sync_unlock(&write_queue.queue_sync);
 523 }
 524
 525 /* Get subbuffers count in busy list */
 526 /* XXX Think abount lock */
 527 int get_busy_buffers_count(void)
 528 {
 529         return queue_busy_last_element;
 530 }
 531
 532 /* Get memory pages count in subbuffer */
 533 int get_pages_count_in_subbuffer(void)
 534 {
 535 /* Return 1 if pages order 0, or 2 of power pages_order_in_subbuffer otherwise */
 536         return (pages_order_in_subbuffer) ? 2 << (pages_order_in_subbuffer - 1) : 1;
 537 }