drivers/android/binder_alloc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* binder_alloc.c
   3  *
   4  * Android IPC Subsystem
   5  *
   6  * Copyright (C) 2007-2017 Google, Inc.
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/list.h>
  12 #include <linux/sched/mm.h>
  13 #include <linux/module.h>
  14 #include <linux/rtmutex.h>
  15 #include <linux/rbtree.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/slab.h>
  19 #include <linux/sched.h>
  20 #include <linux/list_lru.h>
  21 #include <linux/ratelimit.h>
  22 #include <asm/cacheflush.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/highmem.h>
  25 #include <linux/sizes.h>
  26 #include "binder_alloc.h"
  27 #include "binder_trace.h"
  28
  29 struct list_lru binder_freelist;
  30
  31 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  32
  33 enum {
  34         BINDER_DEBUG_USER_ERROR             = 1U << 0,
  35         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  36         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  37         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  38 };
  39 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
  40
  41 module_param_named(debug_mask, binder_alloc_debug_mask,
  42                    uint, 0644);
  43
  44 #define binder_alloc_debug(mask, x...) \
  45         do { \
  46                 if (binder_alloc_debug_mask & mask) \
  47                         pr_info_ratelimited(x); \
  48         } while (0)
  49
  50 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  51 {
  52         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  53 }
  54
  55 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  56 {
  57         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  58 }
  59
  60 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  61                                        struct binder_buffer *buffer)
  62 {
  63         if (list_is_last(&buffer->entry, &alloc->buffers))
  64                 return alloc->buffer + alloc->buffer_size - buffer->user_data;
  65         return binder_buffer_next(buffer)->user_data - buffer->user_data;
  66 }
  67
  68 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  69                                       struct binder_buffer *new_buffer)
  70 {
  71         struct rb_node **p = &alloc->free_buffers.rb_node;
  72         struct rb_node *parent = NULL;
  73         struct binder_buffer *buffer;
  74         size_t buffer_size;
  75         size_t new_buffer_size;
  76
  77         BUG_ON(!new_buffer->free);
  78
  79         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  80
  81         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  82                      "%d: add free buffer, size %zd, at %pK\n",
  83                       alloc->pid, new_buffer_size, new_buffer);
  84
  85         while (*p) {
  86                 parent = *p;
  87                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  88                 BUG_ON(!buffer->free);
  89
  90                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  91
  92                 if (new_buffer_size < buffer_size)
  93                         p = &parent->rb_left;
  94                 else
  95                         p = &parent->rb_right;
  96         }
  97         rb_link_node(&new_buffer->rb_node, parent, p);
  98         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
  99 }
 100
 101 static void binder_insert_allocated_buffer_locked(
 102                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 103 {
 104         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 105         struct rb_node *parent = NULL;
 106         struct binder_buffer *buffer;
 107
 108         BUG_ON(new_buffer->free);
 109
 110         while (*p) {
 111                 parent = *p;
 112                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 113                 BUG_ON(buffer->free);
 114
 115                 if (new_buffer->user_data < buffer->user_data)
 116                         p = &parent->rb_left;
 117                 else if (new_buffer->user_data > buffer->user_data)
 118                         p = &parent->rb_right;
 119                 else
 120                         BUG();
 121         }
 122         rb_link_node(&new_buffer->rb_node, parent, p);
 123         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 124 }
 125
 126 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 127                 struct binder_alloc *alloc,
 128                 unsigned long user_ptr)
 129 {
 130         struct rb_node *n = alloc->allocated_buffers.rb_node;
 131         struct binder_buffer *buffer;
 132
 133         while (n) {
 134                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 135                 BUG_ON(buffer->free);
 136
 137                 if (user_ptr < buffer->user_data) {
 138                         n = n->rb_left;
 139                 } else if (user_ptr > buffer->user_data) {
 140                         n = n->rb_right;
 141                 } else {
 142                         /*
 143                          * Guard against user threads attempting to
 144                          * free the buffer when in use by kernel or
 145                          * after it's already been freed.
 146                          */
 147                         if (!buffer->allow_user_free)
 148                                 return ERR_PTR(-EPERM);
 149                         buffer->allow_user_free = 0;
 150                         return buffer;
 151                 }
 152         }
 153         return NULL;
 154 }
 155
 156 /**
 157  * binder_alloc_prepare_to_free() - get buffer given user ptr
 158  * @alloc:      binder_alloc for this proc
 159  * @user_ptr:   User pointer to buffer data
 160  *
 161  * Validate userspace pointer to buffer data and return buffer corresponding to
 162  * that user pointer. Search the rb tree for buffer that matches user data
 163  * pointer.
 164  *
 165  * Return:      Pointer to buffer or NULL
 166  */
 167 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 168                                                    unsigned long user_ptr)
 169 {
 170         struct binder_buffer *buffer;
 171
 172         spin_lock(&alloc->lock);
 173         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 174         spin_unlock(&alloc->lock);
 175         return buffer;
 176 }
 177
 178 static inline void
 179 binder_set_installed_page(struct binder_lru_page *lru_page,
 180                           struct page *page)
 181 {
 182         /* Pairs with acquire in binder_get_installed_page() */
 183         smp_store_release(&lru_page->page_ptr, page);
 184 }
 185
 186 static inline struct page *
 187 binder_get_installed_page(struct binder_lru_page *lru_page)
 188 {
 189         /* Pairs with release in binder_set_installed_page() */
 190         return smp_load_acquire(&lru_page->page_ptr);
 191 }
 192
 193 static void binder_lru_freelist_add(struct binder_alloc *alloc,
 194                                     unsigned long start, unsigned long end)
 195 {
 196         struct binder_lru_page *page;
 197         unsigned long page_addr;
 198
 199         trace_binder_update_page_range(alloc, false, start, end);
 200
 201         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 202                 size_t index;
 203                 int ret;
 204
 205                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 206                 page = &alloc->pages[index];
 207
 208                 if (!binder_get_installed_page(page))
 209                         continue;
 210
 211                 trace_binder_free_lru_start(alloc, index);
 212
 213                 ret = list_lru_add_obj(&binder_freelist, &page->lru);
 214                 WARN_ON(!ret);
 215
 216                 trace_binder_free_lru_end(alloc, index);
 217         }
 218 }
 219
 220 static int binder_install_single_page(struct binder_alloc *alloc,
 221                                       struct binder_lru_page *lru_page,
 222                                       unsigned long addr)
 223 {
 224         struct page *page;
 225         int ret = 0;
 226
 227         if (!mmget_not_zero(alloc->mm))
 228                 return -ESRCH;
 229
 230         /*
 231          * Protected with mmap_sem in write mode as multiple tasks
 232          * might race to install the same page.
 233          */
 234         mmap_write_lock(alloc->mm);
 235         if (binder_get_installed_page(lru_page))
 236                 goto out;
 237
 238         if (!alloc->vma) {
 239                 pr_err("%d: %s failed, no vma\n", alloc->pid, __func__);
 240                 ret = -ESRCH;
 241                 goto out;
 242         }
 243
 244         page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);
 245         if (!page) {
 246                 pr_err("%d: failed to allocate page\n", alloc->pid);
 247                 ret = -ENOMEM;
 248                 goto out;
 249         }
 250
 251         ret = vm_insert_page(alloc->vma, addr, page);
 252         if (ret) {
 253                 pr_err("%d: %s failed to insert page at offset %lx with %d\n",
 254                        alloc->pid, __func__, addr - alloc->buffer, ret);
 255                 __free_page(page);
 256                 ret = -ENOMEM;
 257                 goto out;
 258         }
 259
 260         /* Mark page installation complete and safe to use */
 261         binder_set_installed_page(lru_page, page);
 262 out:
 263         mmap_write_unlock(alloc->mm);
 264         mmput_async(alloc->mm);
 265         return ret;
 266 }
 267
 268 static int binder_install_buffer_pages(struct binder_alloc *alloc,
 269                                        struct binder_buffer *buffer,
 270                                        size_t size)
 271 {
 272         struct binder_lru_page *page;
 273         unsigned long start, final;
 274         unsigned long page_addr;
 275
 276         start = buffer->user_data & PAGE_MASK;
 277         final = PAGE_ALIGN(buffer->user_data + size);
 278
 279         for (page_addr = start; page_addr < final; page_addr += PAGE_SIZE) {
 280                 unsigned long index;
 281                 int ret;
 282
 283                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 284                 page = &alloc->pages[index];
 285
 286                 if (binder_get_installed_page(page))
 287                         continue;
 288
 289                 trace_binder_alloc_page_start(alloc, index);
 290
 291                 ret = binder_install_single_page(alloc, page, page_addr);
 292                 if (ret)
 293                         return ret;
 294
 295                 trace_binder_alloc_page_end(alloc, index);
 296         }
 297
 298         return 0;
 299 }
 300
 301 /* The range of pages should exclude those shared with other buffers */
 302 static void binder_lru_freelist_del(struct binder_alloc *alloc,
 303                                     unsigned long start, unsigned long end)
 304 {
 305         struct binder_lru_page *page;
 306         unsigned long page_addr;
 307
 308         trace_binder_update_page_range(alloc, true, start, end);
 309
 310         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 311                 unsigned long index;
 312                 bool on_lru;
 313
 314                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 315                 page = &alloc->pages[index];
 316
 317                 if (page->page_ptr) {
 318                         trace_binder_alloc_lru_start(alloc, index);
 319
 320                         on_lru = list_lru_del_obj(&binder_freelist, &page->lru);
 321                         WARN_ON(!on_lru);
 322
 323                         trace_binder_alloc_lru_end(alloc, index);
 324                         continue;
 325                 }
 326
 327                 if (index + 1 > alloc->pages_high)
 328                         alloc->pages_high = index + 1;
 329         }
 330 }
 331
 332 static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
 333                 struct vm_area_struct *vma)
 334 {
 335         /* pairs with smp_load_acquire in binder_alloc_get_vma() */
 336         smp_store_release(&alloc->vma, vma);
 337 }
 338
 339 static inline struct vm_area_struct *binder_alloc_get_vma(
 340                 struct binder_alloc *alloc)
 341 {
 342         /* pairs with smp_store_release in binder_alloc_set_vma() */
 343         return smp_load_acquire(&alloc->vma);
 344 }
 345
 346 static void debug_no_space_locked(struct binder_alloc *alloc)
 347 {
 348         size_t largest_alloc_size = 0;
 349         struct binder_buffer *buffer;
 350         size_t allocated_buffers = 0;
 351         size_t largest_free_size = 0;
 352         size_t total_alloc_size = 0;
 353         size_t total_free_size = 0;
 354         size_t free_buffers = 0;
 355         size_t buffer_size;
 356         struct rb_node *n;
 357
 358         for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) {
 359                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 360                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 361                 allocated_buffers++;
 362                 total_alloc_size += buffer_size;
 363                 if (buffer_size > largest_alloc_size)
 364                         largest_alloc_size = buffer_size;
 365         }
 366
 367         for (n = rb_first(&alloc->free_buffers); n; n = rb_next(n)) {
 368                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 369                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 370                 free_buffers++;
 371                 total_free_size += buffer_size;
 372                 if (buffer_size > largest_free_size)
 373                         largest_free_size = buffer_size;
 374         }
 375
 376         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 377                            "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 378                            total_alloc_size, allocated_buffers,
 379                            largest_alloc_size, total_free_size,
 380                            free_buffers, largest_free_size);
 381 }
 382
 383 static bool debug_low_async_space_locked(struct binder_alloc *alloc)
 384 {
 385         /*
 386          * Find the amount and size of buffers allocated by the current caller;
 387          * The idea is that once we cross the threshold, whoever is responsible
 388          * for the low async space is likely to try to send another async txn,
 389          * and at some point we'll catch them in the act. This is more efficient
 390          * than keeping a map per pid.
 391          */
 392         struct binder_buffer *buffer;
 393         size_t total_alloc_size = 0;
 394         int pid = current->tgid;
 395         size_t num_buffers = 0;
 396         struct rb_node *n;
 397
 398         /*
 399          * Only start detecting spammers once we have less than 20% of async
 400          * space left (which is less than 10% of total buffer size).
 401          */
 402         if (alloc->free_async_space >= alloc->buffer_size / 10) {
 403                 alloc->oneway_spam_detected = false;
 404                 return false;
 405         }
 406
 407         for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 408                  n = rb_next(n)) {
 409                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 410                 if (buffer->pid != pid)
 411                         continue;
 412                 if (!buffer->async_transaction)
 413                         continue;
 414                 total_alloc_size += binder_alloc_buffer_size(alloc, buffer);
 415                 num_buffers++;
 416         }
 417
 418         /*
 419          * Warn if this pid has more than 50 transactions, or more than 50% of
 420          * async space (which is 25% of total buffer size). Oneway spam is only
 421          * detected when the threshold is exceeded.
 422          */
 423         if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
 424                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 425                              "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
 426                               alloc->pid, pid, num_buffers, total_alloc_size);
 427                 if (!alloc->oneway_spam_detected) {
 428                         alloc->oneway_spam_detected = true;
 429                         return true;
 430                 }
 431         }
 432         return false;
 433 }
 434
 435 /* Callers preallocate @new_buffer, it is freed by this function if unused */
 436 static struct binder_buffer *binder_alloc_new_buf_locked(
 437                                 struct binder_alloc *alloc,
 438                                 struct binder_buffer *new_buffer,
 439                                 size_t size,
 440                                 int is_async)
 441 {
 442         struct rb_node *n = alloc->free_buffers.rb_node;
 443         struct rb_node *best_fit = NULL;
 444         struct binder_buffer *buffer;
 445         unsigned long next_used_page;
 446         unsigned long curr_last_page;
 447         size_t buffer_size;
 448
 449         if (is_async && alloc->free_async_space < size) {
 450                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 451                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 452                               alloc->pid, size);
 453                 buffer = ERR_PTR(-ENOSPC);
 454                 goto out;
 455         }
 456
 457         while (n) {
 458                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 459                 BUG_ON(!buffer->free);
 460                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 461
 462                 if (size < buffer_size) {
 463                         best_fit = n;
 464                         n = n->rb_left;
 465                 } else if (size > buffer_size) {
 466                         n = n->rb_right;
 467                 } else {
 468                         best_fit = n;
 469                         break;
 470                 }
 471         }
 472
 473         if (unlikely(!best_fit)) {
 474                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 475                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 476                                    alloc->pid, size);
 477                 debug_no_space_locked(alloc);
 478                 buffer = ERR_PTR(-ENOSPC);
 479                 goto out;
 480         }
 481
 482         if (buffer_size != size) {
 483                 /* Found an oversized buffer and needs to be split */
 484                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 485                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 486
 487                 WARN_ON(n || buffer_size == size);
 488                 new_buffer->user_data = buffer->user_data + size;
 489                 list_add(&new_buffer->entry, &buffer->entry);
 490                 new_buffer->free = 1;
 491                 binder_insert_free_buffer(alloc, new_buffer);
 492                 new_buffer = NULL;
 493         }
 494
 495         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 496                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 497                       alloc->pid, size, buffer, buffer_size);
 498
 499         /*
 500          * Now we remove the pages from the freelist. A clever calculation
 501          * with buffer_size determines if the last page is shared with an
 502          * adjacent in-use buffer. In such case, the page has been already
 503          * removed from the freelist so we trim our range short.
 504          */
 505         next_used_page = (buffer->user_data + buffer_size) & PAGE_MASK;
 506         curr_last_page = PAGE_ALIGN(buffer->user_data + size);
 507         binder_lru_freelist_del(alloc, PAGE_ALIGN(buffer->user_data),
 508                                 min(next_used_page, curr_last_page));
 509
 510         rb_erase(&buffer->rb_node, &alloc->free_buffers);
 511         buffer->free = 0;
 512         buffer->allow_user_free = 0;
 513         binder_insert_allocated_buffer_locked(alloc, buffer);
 514         buffer->async_transaction = is_async;
 515         buffer->oneway_spam_suspect = false;
 516         if (is_async) {
 517                 alloc->free_async_space -= size;
 518                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 519                              "%d: binder_alloc_buf size %zd async free %zd\n",
 520                               alloc->pid, size, alloc->free_async_space);
 521                 if (debug_low_async_space_locked(alloc))
 522                         buffer->oneway_spam_suspect = true;
 523         }
 524
 525 out:
 526         /* Discard possibly unused new_buffer */
 527         kfree(new_buffer);
 528         return buffer;
 529 }
 530
 531 /* Calculate the sanitized total size, returns 0 for invalid request */
 532 static inline size_t sanitized_size(size_t data_size,
 533                                     size_t offsets_size,
 534                                     size_t extra_buffers_size)
 535 {
 536         size_t total, tmp;
 537
 538         /* Align to pointer size and check for overflows */
 539         tmp = ALIGN(data_size, sizeof(void *)) +
 540                 ALIGN(offsets_size, sizeof(void *));
 541         if (tmp < data_size || tmp < offsets_size)
 542                 return 0;
 543         total = tmp + ALIGN(extra_buffers_size, sizeof(void *));
 544         if (total < tmp || total < extra_buffers_size)
 545                 return 0;
 546
 547         /* Pad 0-sized buffers so they get a unique address */
 548         total = max(total, sizeof(void *));
 549
 550         return total;
 551 }
 552
 553 /**
 554  * binder_alloc_new_buf() - Allocate a new binder buffer
 555  * @alloc:              binder_alloc for this proc
 556  * @data_size:          size of user data buffer
 557  * @offsets_size:       user specified buffer offset
 558  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 559  * @is_async:           buffer for async transaction
 560  *
 561  * Allocate a new buffer given the requested sizes. Returns
 562  * the kernel version of the buffer pointer. The size allocated
 563  * is the sum of the three given sizes (each rounded up to
 564  * pointer-sized boundary)
 565  *
 566  * Return:      The allocated buffer or %ERR_PTR(-errno) if error
 567  */
 568 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 569                                            size_t data_size,
 570                                            size_t offsets_size,
 571                                            size_t extra_buffers_size,
 572                                            int is_async)
 573 {
 574         struct binder_buffer *buffer, *next;
 575         size_t size;
 576         int ret;
 577
 578         /* Check binder_alloc is fully initialized */
 579         if (!binder_alloc_get_vma(alloc)) {
 580                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 581                                    "%d: binder_alloc_buf, no vma\n",
 582                                    alloc->pid);
 583                 return ERR_PTR(-ESRCH);
 584         }
 585
 586         size = sanitized_size(data_size, offsets_size, extra_buffers_size);
 587         if (unlikely(!size)) {
 588                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 589                                    "%d: got transaction with invalid size %zd-%zd-%zd\n",
 590                                    alloc->pid, data_size, offsets_size,
 591                                    extra_buffers_size);
 592                 return ERR_PTR(-EINVAL);
 593         }
 594
 595         /* Preallocate the next buffer */
 596         next = kzalloc(sizeof(*next), GFP_KERNEL);
 597         if (!next)
 598                 return ERR_PTR(-ENOMEM);
 599
 600         spin_lock(&alloc->lock);
 601         buffer = binder_alloc_new_buf_locked(alloc, next, size, is_async);
 602         if (IS_ERR(buffer)) {
 603                 spin_unlock(&alloc->lock);
 604                 goto out;
 605         }
 606
 607         buffer->data_size = data_size;
 608         buffer->offsets_size = offsets_size;
 609         buffer->extra_buffers_size = extra_buffers_size;
 610         buffer->pid = current->tgid;
 611         spin_unlock(&alloc->lock);
 612
 613         ret = binder_install_buffer_pages(alloc, buffer, size);
 614         if (ret) {
 615                 binder_alloc_free_buf(alloc, buffer);
 616                 buffer = ERR_PTR(ret);
 617         }
 618 out:
 619         return buffer;
 620 }
 621
 622 static unsigned long buffer_start_page(struct binder_buffer *buffer)
 623 {
 624         return buffer->user_data & PAGE_MASK;
 625 }
 626
 627 static unsigned long prev_buffer_end_page(struct binder_buffer *buffer)
 628 {
 629         return (buffer->user_data - 1) & PAGE_MASK;
 630 }
 631
 632 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 633                                       struct binder_buffer *buffer)
 634 {
 635         struct binder_buffer *prev, *next;
 636
 637         if (PAGE_ALIGNED(buffer->user_data))
 638                 goto skip_freelist;
 639
 640         BUG_ON(alloc->buffers.next == &buffer->entry);
 641         prev = binder_buffer_prev(buffer);
 642         BUG_ON(!prev->free);
 643         if (prev_buffer_end_page(prev) == buffer_start_page(buffer))
 644                 goto skip_freelist;
 645
 646         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 647                 next = binder_buffer_next(buffer);
 648                 if (buffer_start_page(next) == buffer_start_page(buffer))
 649                         goto skip_freelist;
 650         }
 651
 652         binder_lru_freelist_add(alloc, buffer_start_page(buffer),
 653                                 buffer_start_page(buffer) + PAGE_SIZE);
 654 skip_freelist:
 655         list_del(&buffer->entry);
 656         kfree(buffer);
 657 }
 658
 659 static void binder_free_buf_locked(struct binder_alloc *alloc,
 660                                    struct binder_buffer *buffer)
 661 {
 662         size_t size, buffer_size;
 663
 664         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 665
 666         size = ALIGN(buffer->data_size, sizeof(void *)) +
 667                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 668                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 669
 670         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 671                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 672                       alloc->pid, buffer, size, buffer_size);
 673
 674         BUG_ON(buffer->free);
 675         BUG_ON(size > buffer_size);
 676         BUG_ON(buffer->transaction != NULL);
 677         BUG_ON(buffer->user_data < alloc->buffer);
 678         BUG_ON(buffer->user_data > alloc->buffer + alloc->buffer_size);
 679
 680         if (buffer->async_transaction) {
 681                 alloc->free_async_space += buffer_size;
 682                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 683                              "%d: binder_free_buf size %zd async free %zd\n",
 684                               alloc->pid, size, alloc->free_async_space);
 685         }
 686
 687         binder_lru_freelist_add(alloc, PAGE_ALIGN(buffer->user_data),
 688                                 (buffer->user_data + buffer_size) & PAGE_MASK);
 689
 690         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 691         buffer->free = 1;
 692         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 693                 struct binder_buffer *next = binder_buffer_next(buffer);
 694
 695                 if (next->free) {
 696                         rb_erase(&next->rb_node, &alloc->free_buffers);
 697                         binder_delete_free_buffer(alloc, next);
 698                 }
 699         }
 700         if (alloc->buffers.next != &buffer->entry) {
 701                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 702
 703                 if (prev->free) {
 704                         binder_delete_free_buffer(alloc, buffer);
 705                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 706                         buffer = prev;
 707                 }
 708         }
 709         binder_insert_free_buffer(alloc, buffer);
 710 }
 711
 712 /**
 713  * binder_alloc_get_page() - get kernel pointer for given buffer offset
 714  * @alloc: binder_alloc for this proc
 715  * @buffer: binder buffer to be accessed
 716  * @buffer_offset: offset into @buffer data
 717  * @pgoffp: address to copy final page offset to
 718  *
 719  * Lookup the struct page corresponding to the address
 720  * at @buffer_offset into @buffer->user_data. If @pgoffp is not
 721  * NULL, the byte-offset into the page is written there.
 722  *
 723  * The caller is responsible to ensure that the offset points
 724  * to a valid address within the @buffer and that @buffer is
 725  * not freeable by the user. Since it can't be freed, we are
 726  * guaranteed that the corresponding elements of @alloc->pages[]
 727  * cannot change.
 728  *
 729  * Return: struct page
 730  */
 731 static struct page *binder_alloc_get_page(struct binder_alloc *alloc,
 732                                           struct binder_buffer *buffer,
 733                                           binder_size_t buffer_offset,
 734                                           pgoff_t *pgoffp)
 735 {
 736         binder_size_t buffer_space_offset = buffer_offset +
 737                 (buffer->user_data - alloc->buffer);
 738         pgoff_t pgoff = buffer_space_offset & ~PAGE_MASK;
 739         size_t index = buffer_space_offset >> PAGE_SHIFT;
 740         struct binder_lru_page *lru_page;
 741
 742         lru_page = &alloc->pages[index];
 743         *pgoffp = pgoff;
 744         return lru_page->page_ptr;
 745 }
 746
 747 /**
 748  * binder_alloc_clear_buf() - zero out buffer
 749  * @alloc: binder_alloc for this proc
 750  * @buffer: binder buffer to be cleared
 751  *
 752  * memset the given buffer to 0
 753  */
 754 static void binder_alloc_clear_buf(struct binder_alloc *alloc,
 755                                    struct binder_buffer *buffer)
 756 {
 757         size_t bytes = binder_alloc_buffer_size(alloc, buffer);
 758         binder_size_t buffer_offset = 0;
 759
 760         while (bytes) {
 761                 unsigned long size;
 762                 struct page *page;
 763                 pgoff_t pgoff;
 764
 765                 page = binder_alloc_get_page(alloc, buffer,
 766                                              buffer_offset, &pgoff);
 767                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
 768                 memset_page(page, pgoff, 0, size);
 769                 bytes -= size;
 770                 buffer_offset += size;
 771         }
 772 }
 773
 774 /**
 775  * binder_alloc_free_buf() - free a binder buffer
 776  * @alloc:      binder_alloc for this proc
 777  * @buffer:     kernel pointer to buffer
 778  *
 779  * Free the buffer allocated via binder_alloc_new_buf()
 780  */
 781 void binder_alloc_free_buf(struct binder_alloc *alloc,
 782                             struct binder_buffer *buffer)
 783 {
 784         /*
 785          * We could eliminate the call to binder_alloc_clear_buf()
 786          * from binder_alloc_deferred_release() by moving this to
 787          * binder_free_buf_locked(). However, that could
 788          * increase contention for the alloc->lock if clear_on_free
 789          * is used frequently for large buffers. This lock is not
 790          * needed for correctness here.
 791          */
 792         if (buffer->clear_on_free) {
 793                 binder_alloc_clear_buf(alloc, buffer);
 794                 buffer->clear_on_free = false;
 795         }
 796         spin_lock(&alloc->lock);
 797         binder_free_buf_locked(alloc, buffer);
 798         spin_unlock(&alloc->lock);
 799 }
 800
 801 /**
 802  * binder_alloc_mmap_handler() - map virtual address space for proc
 803  * @alloc:      alloc structure for this proc
 804  * @vma:        vma passed to mmap()
 805  *
 806  * Called by binder_mmap() to initialize the space specified in
 807  * vma for allocating binder buffers
 808  *
 809  * Return:
 810  *      0 = success
 811  *      -EBUSY = address space already mapped
 812  *      -ENOMEM = failed to map memory to given address space
 813  */
 814 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 815                               struct vm_area_struct *vma)
 816 {
 817         struct binder_buffer *buffer;
 818         const char *failure_string;
 819         int ret, i;
 820
 821         if (unlikely(vma->vm_mm != alloc->mm)) {
 822                 ret = -EINVAL;
 823                 failure_string = "invalid vma->vm_mm";
 824                 goto err_invalid_mm;
 825         }
 826
 827         mutex_lock(&binder_alloc_mmap_lock);
 828         if (alloc->buffer_size) {
 829                 ret = -EBUSY;
 830                 failure_string = "already mapped";
 831                 goto err_already_mapped;
 832         }
 833         alloc->buffer_size = min_t(unsigned long, vma->vm_end - vma->vm_start,
 834                                    SZ_4M);
 835         mutex_unlock(&binder_alloc_mmap_lock);
 836
 837         alloc->buffer = vma->vm_start;
 838
 839         alloc->pages = kcalloc(alloc->buffer_size / PAGE_SIZE,
 840                                sizeof(alloc->pages[0]),
 841                                GFP_KERNEL);
 842         if (alloc->pages == NULL) {
 843                 ret = -ENOMEM;
 844                 failure_string = "alloc page array";
 845                 goto err_alloc_pages_failed;
 846         }
 847
 848         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 849                 alloc->pages[i].alloc = alloc;
 850                 INIT_LIST_HEAD(&alloc->pages[i].lru);
 851         }
 852
 853         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 854         if (!buffer) {
 855                 ret = -ENOMEM;
 856                 failure_string = "alloc buffer struct";
 857                 goto err_alloc_buf_struct_failed;
 858         }
 859
 860         buffer->user_data = alloc->buffer;
 861         list_add(&buffer->entry, &alloc->buffers);
 862         buffer->free = 1;
 863         binder_insert_free_buffer(alloc, buffer);
 864         alloc->free_async_space = alloc->buffer_size / 2;
 865
 866         /* Signal binder_alloc is fully initialized */
 867         binder_alloc_set_vma(alloc, vma);
 868
 869         return 0;
 870
 871 err_alloc_buf_struct_failed:
 872         kfree(alloc->pages);
 873         alloc->pages = NULL;
 874 err_alloc_pages_failed:
 875         alloc->buffer = 0;
 876         mutex_lock(&binder_alloc_mmap_lock);
 877         alloc->buffer_size = 0;
 878 err_already_mapped:
 879         mutex_unlock(&binder_alloc_mmap_lock);
 880 err_invalid_mm:
 881         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 882                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 883                            alloc->pid, vma->vm_start, vma->vm_end,
 884                            failure_string, ret);
 885         return ret;
 886 }
 887
 888
 889 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 890 {
 891         struct rb_node *n;
 892         int buffers, page_count;
 893         struct binder_buffer *buffer;
 894
 895         buffers = 0;
 896         spin_lock(&alloc->lock);
 897         BUG_ON(alloc->vma);
 898
 899         while ((n = rb_first(&alloc->allocated_buffers))) {
 900                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 901
 902                 /* Transaction should already have been freed */
 903                 BUG_ON(buffer->transaction);
 904
 905                 if (buffer->clear_on_free) {
 906                         binder_alloc_clear_buf(alloc, buffer);
 907                         buffer->clear_on_free = false;
 908                 }
 909                 binder_free_buf_locked(alloc, buffer);
 910                 buffers++;
 911         }
 912
 913         while (!list_empty(&alloc->buffers)) {
 914                 buffer = list_first_entry(&alloc->buffers,
 915                                           struct binder_buffer, entry);
 916                 WARN_ON(!buffer->free);
 917
 918                 list_del(&buffer->entry);
 919                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 920                 kfree(buffer);
 921         }
 922
 923         page_count = 0;
 924         if (alloc->pages) {
 925                 int i;
 926
 927                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 928                         unsigned long page_addr;
 929                         bool on_lru;
 930
 931                         if (!alloc->pages[i].page_ptr)
 932                                 continue;
 933
 934                         on_lru = list_lru_del_obj(&binder_freelist,
 935                                                   &alloc->pages[i].lru);
 936                         page_addr = alloc->buffer + i * PAGE_SIZE;
 937                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 938                                      "%s: %d: page %d %s\n",
 939                                      __func__, alloc->pid, i,
 940                                      on_lru ? "on lru" : "active");
 941                         __free_page(alloc->pages[i].page_ptr);
 942                         page_count++;
 943                 }
 944                 kfree(alloc->pages);
 945         }
 946         spin_unlock(&alloc->lock);
 947         if (alloc->mm)
 948                 mmdrop(alloc->mm);
 949
 950         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 951                      "%s: %d buffers %d, pages %d\n",
 952                      __func__, alloc->pid, buffers, page_count);
 953 }
 954
 955 /**
 956  * binder_alloc_print_allocated() - print buffer info
 957  * @m:     seq_file for output via seq_printf()
 958  * @alloc: binder_alloc for this proc
 959  *
 960  * Prints information about every buffer associated with
 961  * the binder_alloc state to the given seq_file
 962  */
 963 void binder_alloc_print_allocated(struct seq_file *m,
 964                                   struct binder_alloc *alloc)
 965 {
 966         struct binder_buffer *buffer;
 967         struct rb_node *n;
 968
 969         spin_lock(&alloc->lock);
 970         for (n = rb_first(&alloc->allocated_buffers); n; n = rb_next(n)) {
 971                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 972                 seq_printf(m, "  buffer %d: %lx size %zd:%zd:%zd %s\n",
 973                            buffer->debug_id,
 974                            buffer->user_data - alloc->buffer,
 975                            buffer->data_size, buffer->offsets_size,
 976                            buffer->extra_buffers_size,
 977                            buffer->transaction ? "active" : "delivered");
 978         }
 979         spin_unlock(&alloc->lock);
 980 }
 981
 982 /**
 983  * binder_alloc_print_pages() - print page usage
 984  * @m:     seq_file for output via seq_printf()
 985  * @alloc: binder_alloc for this proc
 986  */
 987 void binder_alloc_print_pages(struct seq_file *m,
 988                               struct binder_alloc *alloc)
 989 {
 990         struct binder_lru_page *page;
 991         int i;
 992         int active = 0;
 993         int lru = 0;
 994         int free = 0;
 995
 996         spin_lock(&alloc->lock);
 997         /*
 998          * Make sure the binder_alloc is fully initialized, otherwise we might
 999          * read inconsistent state.
1000          */
1001         if (binder_alloc_get_vma(alloc) != NULL) {
1002                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
1003                         page = &alloc->pages[i];
1004                         if (!page->page_ptr)
1005                                 free++;
1006                         else if (list_empty(&page->lru))
1007                                 active++;
1008                         else
1009                                 lru++;
1010                 }
1011         }
1012         spin_unlock(&alloc->lock);
1013         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
1014         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
1015 }
1016
1017 /**
1018  * binder_alloc_get_allocated_count() - return count of buffers
1019  * @alloc: binder_alloc for this proc
1020  *
1021  * Return: count of allocated buffers
1022  */
1023 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
1024 {
1025         struct rb_node *n;
1026         int count = 0;
1027
1028         spin_lock(&alloc->lock);
1029         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
1030                 count++;
1031         spin_unlock(&alloc->lock);
1032         return count;
1033 }
1034
1035
1036 /**
1037  * binder_alloc_vma_close() - invalidate address space
1038  * @alloc: binder_alloc for this proc
1039  *
1040  * Called from binder_vma_close() when releasing address space.
1041  * Clears alloc->vma to prevent new incoming transactions from
1042  * allocating more buffers.
1043  */
1044 void binder_alloc_vma_close(struct binder_alloc *alloc)
1045 {
1046         binder_alloc_set_vma(alloc, NULL);
1047 }
1048
1049 /**
1050  * binder_alloc_free_page() - shrinker callback to free pages
1051  * @item:   item to free
1052  * @lock:   lock protecting the item
1053  * @cb_arg: callback argument
1054  *
1055  * Called from list_lru_walk() in binder_shrink_scan() to free
1056  * up pages when the system is under memory pressure.
1057  */
1058 enum lru_status binder_alloc_free_page(struct list_head *item,
1059                                        struct list_lru_one *lru,
1060                                        spinlock_t *lock,
1061                                        void *cb_arg)
1062         __must_hold(lock)
1063 {
1064         struct binder_lru_page *page = container_of(item, typeof(*page), lru);
1065         struct binder_alloc *alloc = page->alloc;
1066         struct mm_struct *mm = alloc->mm;
1067         struct vm_area_struct *vma;
1068         struct page *page_to_free;
1069         unsigned long page_addr;
1070         size_t index;
1071
1072         if (!mmget_not_zero(mm))
1073                 goto err_mmget;
1074         if (!mmap_read_trylock(mm))
1075                 goto err_mmap_read_lock_failed;
1076         if (!spin_trylock(&alloc->lock))
1077                 goto err_get_alloc_lock_failed;
1078         if (!page->page_ptr)
1079                 goto err_page_already_freed;
1080
1081         index = page - alloc->pages;
1082         page_addr = alloc->buffer + index * PAGE_SIZE;
1083
1084         vma = vma_lookup(mm, page_addr);
1085         if (vma && vma != binder_alloc_get_vma(alloc))
1086                 goto err_invalid_vma;
1087
1088         trace_binder_unmap_kernel_start(alloc, index);
1089
1090         page_to_free = page->page_ptr;
1091         page->page_ptr = NULL;
1092
1093         trace_binder_unmap_kernel_end(alloc, index);
1094
1095         list_lru_isolate(lru, item);
1096         spin_unlock(&alloc->lock);
1097         spin_unlock(lock);
1098
1099         if (vma) {
1100                 trace_binder_unmap_user_start(alloc, index);
1101
1102                 zap_page_range_single(vma, page_addr, PAGE_SIZE, NULL);
1103
1104                 trace_binder_unmap_user_end(alloc, index);
1105         }
1106
1107         mmap_read_unlock(mm);
1108         mmput_async(mm);
1109         __free_page(page_to_free);
1110
1111         spin_lock(lock);
1112         return LRU_REMOVED_RETRY;
1113
1114 err_invalid_vma:
1115 err_page_already_freed:
1116         spin_unlock(&alloc->lock);
1117 err_get_alloc_lock_failed:
1118         mmap_read_unlock(mm);
1119 err_mmap_read_lock_failed:
1120         mmput_async(mm);
1121 err_mmget:
1122         return LRU_SKIP;
1123 }
1124
1125 static unsigned long
1126 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
1127 {
1128         return list_lru_count(&binder_freelist);
1129 }
1130
1131 static unsigned long
1132 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
1133 {
1134         return list_lru_walk(&binder_freelist, binder_alloc_free_page,
1135                             NULL, sc->nr_to_scan);
1136 }
1137
1138 static struct shrinker *binder_shrinker;
1139
1140 /**
1141  * binder_alloc_init() - called by binder_open() for per-proc initialization
1142  * @alloc: binder_alloc for this proc
1143  *
1144  * Called from binder_open() to initialize binder_alloc fields for
1145  * new binder proc
1146  */
1147 void binder_alloc_init(struct binder_alloc *alloc)
1148 {
1149         alloc->pid = current->group_leader->pid;
1150         alloc->mm = current->mm;
1151         mmgrab(alloc->mm);
1152         spin_lock_init(&alloc->lock);
1153         INIT_LIST_HEAD(&alloc->buffers);
1154 }
1155
1156 int binder_alloc_shrinker_init(void)
1157 {
1158         int ret;
1159
1160         ret = list_lru_init(&binder_freelist);
1161         if (ret)
1162                 return ret;
1163
1164         binder_shrinker = shrinker_alloc(0, "android-binder");
1165         if (!binder_shrinker) {
1166                 list_lru_destroy(&binder_freelist);
1167                 return -ENOMEM;
1168         }
1169
1170         binder_shrinker->count_objects = binder_shrink_count;
1171         binder_shrinker->scan_objects = binder_shrink_scan;
1172
1173         shrinker_register(binder_shrinker);
1174
1175         return 0;
1176 }
1177
1178 void binder_alloc_shrinker_exit(void)
1179 {
1180         shrinker_free(binder_shrinker);
1181         list_lru_destroy(&binder_freelist);
1182 }
1183
1184 /**
1185  * check_buffer() - verify that buffer/offset is safe to access
1186  * @alloc: binder_alloc for this proc
1187  * @buffer: binder buffer to be accessed
1188  * @offset: offset into @buffer data
1189  * @bytes: bytes to access from offset
1190  *
1191  * Check that the @offset/@bytes are within the size of the given
1192  * @buffer and that the buffer is currently active and not freeable.
1193  * Offsets must also be multiples of sizeof(u32). The kernel is
1194  * allowed to touch the buffer in two cases:
1195  *
1196  * 1) when the buffer is being created:
1197  *     (buffer->free == 0 && buffer->allow_user_free == 0)
1198  * 2) when the buffer is being torn down:
1199  *     (buffer->free == 0 && buffer->transaction == NULL).
1200  *
1201  * Return: true if the buffer is safe to access
1202  */
1203 static inline bool check_buffer(struct binder_alloc *alloc,
1204                                 struct binder_buffer *buffer,
1205                                 binder_size_t offset, size_t bytes)
1206 {
1207         size_t buffer_size = binder_alloc_buffer_size(alloc, buffer);
1208
1209         return buffer_size >= bytes &&
1210                 offset <= buffer_size - bytes &&
1211                 IS_ALIGNED(offset, sizeof(u32)) &&
1212                 !buffer->free &&
1213                 (!buffer->allow_user_free || !buffer->transaction);
1214 }
1215
1216 /**
1217  * binder_alloc_copy_user_to_buffer() - copy src user to tgt user
1218  * @alloc: binder_alloc for this proc
1219  * @buffer: binder buffer to be accessed
1220  * @buffer_offset: offset into @buffer data
1221  * @from: userspace pointer to source buffer
1222  * @bytes: bytes to copy
1223  *
1224  * Copy bytes from source userspace to target buffer.
1225  *
1226  * Return: bytes remaining to be copied
1227  */
1228 unsigned long
1229 binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
1230                                  struct binder_buffer *buffer,
1231                                  binder_size_t buffer_offset,
1232                                  const void __user *from,
1233                                  size_t bytes)
1234 {
1235         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1236                 return bytes;
1237
1238         while (bytes) {
1239                 unsigned long size;
1240                 unsigned long ret;
1241                 struct page *page;
1242                 pgoff_t pgoff;
1243                 void *kptr;
1244
1245                 page = binder_alloc_get_page(alloc, buffer,
1246                                              buffer_offset, &pgoff);
1247                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1248                 kptr = kmap_local_page(page) + pgoff;
1249                 ret = copy_from_user(kptr, from, size);
1250                 kunmap_local(kptr);
1251                 if (ret)
1252                         return bytes - size + ret;
1253                 bytes -= size;
1254                 from += size;
1255                 buffer_offset += size;
1256         }
1257         return 0;
1258 }
1259
1260 static int binder_alloc_do_buffer_copy(struct binder_alloc *alloc,
1261                                        bool to_buffer,
1262                                        struct binder_buffer *buffer,
1263                                        binder_size_t buffer_offset,
1264                                        void *ptr,
1265                                        size_t bytes)
1266 {
1267         /* All copies must be 32-bit aligned and 32-bit size */
1268         if (!check_buffer(alloc, buffer, buffer_offset, bytes))
1269                 return -EINVAL;
1270
1271         while (bytes) {
1272                 unsigned long size;
1273                 struct page *page;
1274                 pgoff_t pgoff;
1275
1276                 page = binder_alloc_get_page(alloc, buffer,
1277                                              buffer_offset, &pgoff);
1278                 size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
1279                 if (to_buffer)
1280                         memcpy_to_page(page, pgoff, ptr, size);
1281                 else
1282                         memcpy_from_page(ptr, page, pgoff, size);
1283                 bytes -= size;
1284                 pgoff = 0;
1285                 ptr = ptr + size;
1286                 buffer_offset += size;
1287         }
1288         return 0;
1289 }
1290
1291 int binder_alloc_copy_to_buffer(struct binder_alloc *alloc,
1292                                 struct binder_buffer *buffer,
1293                                 binder_size_t buffer_offset,
1294                                 void *src,
1295                                 size_t bytes)
1296 {
1297         return binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset,
1298                                            src, bytes);
1299 }
1300
1301 int binder_alloc_copy_from_buffer(struct binder_alloc *alloc,
1302                                   void *dest,
1303                                   struct binder_buffer *buffer,
1304                                   binder_size_t buffer_offset,
1305                                   size_t bytes)
1306 {
1307         return binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset,
1308                                            dest, bytes);
1309 }