The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/dev/drm2/ttm/ttm_page_alloc_dma.c

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    1 /*
    2  * Copyright 2011 (c) Oracle Corp.
    3 
    4  * Permission is hereby granted, free of charge, to any person obtaining a
    5  * copy of this software and associated documentation files (the "Software"),
    6  * to deal in the Software without restriction, including without limitation
    7  * the rights to use, copy, modify, merge, publish, distribute, sub license,
    8  * and/or sell copies of the Software, and to permit persons to whom the
    9  * Software is furnished to do so, subject to the following conditions:
   10  *
   11  * The above copyright notice and this permission notice (including the
   12  * next paragraph) shall be included in all copies or substantial portions
   13  * of the Software.
   14  *
   15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
   18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   21  * DEALINGS IN THE SOFTWARE.
   22  *
   23  * Author: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
   24  */
   25 
   26 /*
   27  * A simple DMA pool losely based on dmapool.c. It has certain advantages
   28  * over the DMA pools:
   29  * - Pool collects resently freed pages for reuse (and hooks up to
   30  *   the shrinker).
   31  * - Tracks currently in use pages
   32  * - Tracks whether the page is UC, WB or cached (and reverts to WB
   33  *   when freed).
   34  */
   35 
   36 #include <sys/cdefs.h>
   37 __FBSDID("$FreeBSD$");
   38 
   39 #define pr_fmt(fmt) "[TTM] " fmt
   40 
   41 #include <linux/dma-mapping.h>
   42 #include <linux/list.h>
   43 #include <linux/seq_file.h> /* for seq_printf */
   44 #include <linux/slab.h>
   45 #include <linux/spinlock.h>
   46 #include <linux/highmem.h>
   47 #include <linux/mm_types.h>
   48 #include <linux/module.h>
   49 #include <linux/mm.h>
   50 #include <linux/atomic.h>
   51 #include <linux/device.h>
   52 #include <linux/kthread.h>
   53 #include <drm/ttm/ttm_bo_driver.h>
   54 #include <drm/ttm/ttm_page_alloc.h>
   55 #ifdef TTM_HAS_AGP
   56 #include <asm/agp.h>
   57 #endif
   58 
   59 #define NUM_PAGES_TO_ALLOC              (PAGE_SIZE/sizeof(struct page *))
   60 #define SMALL_ALLOCATION                4
   61 #define FREE_ALL_PAGES                  (~0U)
   62 /* times are in msecs */
   63 #define IS_UNDEFINED                    (0)
   64 #define IS_WC                           (1<<1)
   65 #define IS_UC                           (1<<2)
   66 #define IS_CACHED                       (1<<3)
   67 #define IS_DMA32                        (1<<4)
   68 
   69 enum pool_type {
   70         POOL_IS_UNDEFINED,
   71         POOL_IS_WC = IS_WC,
   72         POOL_IS_UC = IS_UC,
   73         POOL_IS_CACHED = IS_CACHED,
   74         POOL_IS_WC_DMA32 = IS_WC | IS_DMA32,
   75         POOL_IS_UC_DMA32 = IS_UC | IS_DMA32,
   76         POOL_IS_CACHED_DMA32 = IS_CACHED | IS_DMA32,
   77 };
   78 /*
   79  * The pool structure. There are usually six pools:
   80  *  - generic (not restricted to DMA32):
   81  *      - write combined, uncached, cached.
   82  *  - dma32 (up to 2^32 - so up 4GB):
   83  *      - write combined, uncached, cached.
   84  * for each 'struct device'. The 'cached' is for pages that are actively used.
   85  * The other ones can be shrunk by the shrinker API if necessary.
   86  * @pools: The 'struct device->dma_pools' link.
   87  * @type: Type of the pool
   88  * @lock: Protects the inuse_list and free_list from concurrnet access. Must be
   89  * used with irqsave/irqrestore variants because pool allocator maybe called
   90  * from delayed work.
   91  * @inuse_list: Pool of pages that are in use. The order is very important and
   92  *   it is in the order that the TTM pages that are put back are in.
   93  * @free_list: Pool of pages that are free to be used. No order requirements.
   94  * @dev: The device that is associated with these pools.
   95  * @size: Size used during DMA allocation.
   96  * @npages_free: Count of available pages for re-use.
   97  * @npages_in_use: Count of pages that are in use.
   98  * @nfrees: Stats when pool is shrinking.
   99  * @nrefills: Stats when the pool is grown.
  100  * @gfp_flags: Flags to pass for alloc_page.
  101  * @name: Name of the pool.
  102  * @dev_name: Name derieved from dev - similar to how dev_info works.
  103  *   Used during shutdown as the dev_info during release is unavailable.
  104  */
  105 struct dma_pool {
  106         struct list_head pools; /* The 'struct device->dma_pools link */
  107         enum pool_type type;
  108         spinlock_t lock;
  109         struct list_head inuse_list;
  110         struct list_head free_list;
  111         struct device *dev;
  112         unsigned size;
  113         unsigned npages_free;
  114         unsigned npages_in_use;
  115         unsigned long nfrees; /* Stats when shrunk. */
  116         unsigned long nrefills; /* Stats when grown. */
  117         gfp_t gfp_flags;
  118         char name[13]; /* "cached dma32" */
  119         char dev_name[64]; /* Constructed from dev */
  120 };
  121 
  122 /*
  123  * The accounting page keeping track of the allocated page along with
  124  * the DMA address.
  125  * @page_list: The link to the 'page_list' in 'struct dma_pool'.
  126  * @vaddr: The virtual address of the page
  127  * @dma: The bus address of the page. If the page is not allocated
  128  *   via the DMA API, it will be -1.
  129  */
  130 struct dma_page {
  131         struct list_head page_list;
  132         void *vaddr;
  133         struct page *p;
  134         dma_addr_t dma;
  135 };
  136 
  137 /*
  138  * Limits for the pool. They are handled without locks because only place where
  139  * they may change is in sysfs store. They won't have immediate effect anyway
  140  * so forcing serialization to access them is pointless.
  141  */
  142 
  143 struct ttm_pool_opts {
  144         unsigned        alloc_size;
  145         unsigned        max_size;
  146         unsigned        small;
  147 };
  148 
  149 /*
  150  * Contains the list of all of the 'struct device' and their corresponding
  151  * DMA pools. Guarded by _mutex->lock.
  152  * @pools: The link to 'struct ttm_pool_manager->pools'
  153  * @dev: The 'struct device' associated with the 'pool'
  154  * @pool: The 'struct dma_pool' associated with the 'dev'
  155  */
  156 struct device_pools {
  157         struct list_head pools;
  158         struct device *dev;
  159         struct dma_pool *pool;
  160 };
  161 
  162 /*
  163  * struct ttm_pool_manager - Holds memory pools for fast allocation
  164  *
  165  * @lock: Lock used when adding/removing from pools
  166  * @pools: List of 'struct device' and 'struct dma_pool' tuples.
  167  * @options: Limits for the pool.
  168  * @npools: Total amount of pools in existence.
  169  * @shrinker: The structure used by [un|]register_shrinker
  170  */
  171 struct ttm_pool_manager {
  172         struct mutex            lock;
  173         struct list_head        pools;
  174         struct ttm_pool_opts    options;
  175         unsigned                npools;
  176         struct shrinker         mm_shrink;
  177         struct kobject          kobj;
  178 };
  179 
  180 static struct ttm_pool_manager *_manager;
  181 
  182 static struct attribute ttm_page_pool_max = {
  183         .name = "pool_max_size",
  184         .mode = S_IRUGO | S_IWUSR
  185 };
  186 static struct attribute ttm_page_pool_small = {
  187         .name = "pool_small_allocation",
  188         .mode = S_IRUGO | S_IWUSR
  189 };
  190 static struct attribute ttm_page_pool_alloc_size = {
  191         .name = "pool_allocation_size",
  192         .mode = S_IRUGO | S_IWUSR
  193 };
  194 
  195 static struct attribute *ttm_pool_attrs[] = {
  196         &ttm_page_pool_max,
  197         &ttm_page_pool_small,
  198         &ttm_page_pool_alloc_size,
  199         NULL
  200 };
  201 
  202 static void ttm_pool_kobj_release(struct kobject *kobj)
  203 {
  204         struct ttm_pool_manager *m =
  205                 container_of(kobj, struct ttm_pool_manager, kobj);
  206         kfree(m);
  207 }
  208 
  209 static ssize_t ttm_pool_store(struct kobject *kobj, struct attribute *attr,
  210                               const char *buffer, size_t size)
  211 {
  212         struct ttm_pool_manager *m =
  213                 container_of(kobj, struct ttm_pool_manager, kobj);
  214         int chars;
  215         unsigned val;
  216         chars = sscanf(buffer, "%u", &val);
  217         if (chars == 0)
  218                 return size;
  219 
  220         /* Convert kb to number of pages */
  221         val = val / (PAGE_SIZE >> 10);
  222 
  223         if (attr == &ttm_page_pool_max)
  224                 m->options.max_size = val;
  225         else if (attr == &ttm_page_pool_small)
  226                 m->options.small = val;
  227         else if (attr == &ttm_page_pool_alloc_size) {
  228                 if (val > NUM_PAGES_TO_ALLOC*8) {
  229                         pr_err("Setting allocation size to %lu is not allowed. Recommended size is %lu\n",
  230                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
  231                                NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
  232                         return size;
  233                 } else if (val > NUM_PAGES_TO_ALLOC) {
  234                         pr_warn("Setting allocation size to larger than %lu is not recommended\n",
  235                                 NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
  236                 }
  237                 m->options.alloc_size = val;
  238         }
  239 
  240         return size;
  241 }
  242 
  243 static ssize_t ttm_pool_show(struct kobject *kobj, struct attribute *attr,
  244                              char *buffer)
  245 {
  246         struct ttm_pool_manager *m =
  247                 container_of(kobj, struct ttm_pool_manager, kobj);
  248         unsigned val = 0;
  249 
  250         if (attr == &ttm_page_pool_max)
  251                 val = m->options.max_size;
  252         else if (attr == &ttm_page_pool_small)
  253                 val = m->options.small;
  254         else if (attr == &ttm_page_pool_alloc_size)
  255                 val = m->options.alloc_size;
  256 
  257         val = val * (PAGE_SIZE >> 10);
  258 
  259         return snprintf(buffer, PAGE_SIZE, "%u\n", val);
  260 }
  261 
  262 static const struct sysfs_ops ttm_pool_sysfs_ops = {
  263         .show = &ttm_pool_show,
  264         .store = &ttm_pool_store,
  265 };
  266 
  267 static struct kobj_type ttm_pool_kobj_type = {
  268         .release = &ttm_pool_kobj_release,
  269         .sysfs_ops = &ttm_pool_sysfs_ops,
  270         .default_attrs = ttm_pool_attrs,
  271 };
  272 
  273 #ifndef CONFIG_X86
  274 static int set_pages_array_wb(struct page **pages, int addrinarray)
  275 {
  276 #ifdef TTM_HAS_AGP
  277         int i;
  278 
  279         for (i = 0; i < addrinarray; i++)
  280                 unmap_page_from_agp(pages[i]);
  281 #endif
  282         return 0;
  283 }
  284 
  285 static int set_pages_array_wc(struct page **pages, int addrinarray)
  286 {
  287 #ifdef TTM_HAS_AGP
  288         int i;
  289 
  290         for (i = 0; i < addrinarray; i++)
  291                 map_page_into_agp(pages[i]);
  292 #endif
  293         return 0;
  294 }
  295 
  296 static int set_pages_array_uc(struct page **pages, int addrinarray)
  297 {
  298 #ifdef TTM_HAS_AGP
  299         int i;
  300 
  301         for (i = 0; i < addrinarray; i++)
  302                 map_page_into_agp(pages[i]);
  303 #endif
  304         return 0;
  305 }
  306 #endif /* for !CONFIG_X86 */
  307 
  308 static int ttm_set_pages_caching(struct dma_pool *pool,
  309                                  struct page **pages, unsigned cpages)
  310 {
  311         int r = 0;
  312         /* Set page caching */
  313         if (pool->type & IS_UC) {
  314                 r = set_pages_array_uc(pages, cpages);
  315                 if (r)
  316                         pr_err("%s: Failed to set %d pages to uc!\n",
  317                                pool->dev_name, cpages);
  318         }
  319         if (pool->type & IS_WC) {
  320                 r = set_pages_array_wc(pages, cpages);
  321                 if (r)
  322                         pr_err("%s: Failed to set %d pages to wc!\n",
  323                                pool->dev_name, cpages);
  324         }
  325         return r;
  326 }
  327 
  328 static void __ttm_dma_free_page(struct dma_pool *pool, struct dma_page *d_page)
  329 {
  330         dma_addr_t dma = d_page->dma;
  331         dma_free_coherent(pool->dev, pool->size, d_page->vaddr, dma);
  332 
  333         kfree(d_page);
  334         d_page = NULL;
  335 }
  336 static struct dma_page *__ttm_dma_alloc_page(struct dma_pool *pool)
  337 {
  338         struct dma_page *d_page;
  339 
  340         d_page = kmalloc(sizeof(struct dma_page), GFP_KERNEL);
  341         if (!d_page)
  342                 return NULL;
  343 
  344         d_page->vaddr = dma_alloc_coherent(pool->dev, pool->size,
  345                                            &d_page->dma,
  346                                            pool->gfp_flags);
  347         if (d_page->vaddr)
  348                 d_page->p = virt_to_page(d_page->vaddr);
  349         else {
  350                 kfree(d_page);
  351                 d_page = NULL;
  352         }
  353         return d_page;
  354 }
  355 static enum pool_type ttm_to_type(int flags, enum ttm_caching_state cstate)
  356 {
  357         enum pool_type type = IS_UNDEFINED;
  358 
  359         if (flags & TTM_PAGE_FLAG_DMA32)
  360                 type |= IS_DMA32;
  361         if (cstate == tt_cached)
  362                 type |= IS_CACHED;
  363         else if (cstate == tt_uncached)
  364                 type |= IS_UC;
  365         else
  366                 type |= IS_WC;
  367 
  368         return type;
  369 }
  370 
  371 static void ttm_pool_update_free_locked(struct dma_pool *pool,
  372                                         unsigned freed_pages)
  373 {
  374         pool->npages_free -= freed_pages;
  375         pool->nfrees += freed_pages;
  376 
  377 }
  378 
  379 /* set memory back to wb and free the pages. */
  380 static void ttm_dma_pages_put(struct dma_pool *pool, struct list_head *d_pages,
  381                               struct page *pages[], unsigned npages)
  382 {
  383         struct dma_page *d_page, *tmp;
  384 
  385         /* Don't set WB on WB page pool. */
  386         if (npages && !(pool->type & IS_CACHED) &&
  387             set_pages_array_wb(pages, npages))
  388                 pr_err("%s: Failed to set %d pages to wb!\n",
  389                        pool->dev_name, npages);
  390 
  391         list_for_each_entry_safe(d_page, tmp, d_pages, page_list) {
  392                 list_del(&d_page->page_list);
  393                 __ttm_dma_free_page(pool, d_page);
  394         }
  395 }
  396 
  397 static void ttm_dma_page_put(struct dma_pool *pool, struct dma_page *d_page)
  398 {
  399         /* Don't set WB on WB page pool. */
  400         if (!(pool->type & IS_CACHED) && set_pages_array_wb(&d_page->p, 1))
  401                 pr_err("%s: Failed to set %d pages to wb!\n",
  402                        pool->dev_name, 1);
  403 
  404         list_del(&d_page->page_list);
  405         __ttm_dma_free_page(pool, d_page);
  406 }
  407 
  408 /*
  409  * Free pages from pool.
  410  *
  411  * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
  412  * number of pages in one go.
  413  *
  414  * @pool: to free the pages from
  415  * @nr_free: If set to true will free all pages in pool
  416  **/
  417 static unsigned ttm_dma_page_pool_free(struct dma_pool *pool, unsigned nr_free)
  418 {
  419         unsigned long irq_flags;
  420         struct dma_page *dma_p, *tmp;
  421         struct page **pages_to_free;
  422         struct list_head d_pages;
  423         unsigned freed_pages = 0,
  424                  npages_to_free = nr_free;
  425 
  426         if (NUM_PAGES_TO_ALLOC < nr_free)
  427                 npages_to_free = NUM_PAGES_TO_ALLOC;
  428 #if 0
  429         if (nr_free > 1) {
  430                 pr_debug("%s: (%s:%d) Attempting to free %d (%d) pages\n",
  431                          pool->dev_name, pool->name, current->pid,
  432                          npages_to_free, nr_free);
  433         }
  434 #endif
  435         pages_to_free = kmalloc(npages_to_free * sizeof(struct page *),
  436                         GFP_KERNEL);
  437 
  438         if (!pages_to_free) {
  439                 pr_err("%s: Failed to allocate memory for pool free operation\n",
  440                        pool->dev_name);
  441                 return 0;
  442         }
  443         INIT_LIST_HEAD(&d_pages);
  444 restart:
  445         spin_lock_irqsave(&pool->lock, irq_flags);
  446 
  447         /* We picking the oldest ones off the list */
  448         list_for_each_entry_safe_reverse(dma_p, tmp, &pool->free_list,
  449                                          page_list) {
  450                 if (freed_pages >= npages_to_free)
  451                         break;
  452 
  453                 /* Move the dma_page from one list to another. */
  454                 list_move(&dma_p->page_list, &d_pages);
  455 
  456                 pages_to_free[freed_pages++] = dma_p->p;
  457                 /* We can only remove NUM_PAGES_TO_ALLOC at a time. */
  458                 if (freed_pages >= NUM_PAGES_TO_ALLOC) {
  459 
  460                         ttm_pool_update_free_locked(pool, freed_pages);
  461                         /**
  462                          * Because changing page caching is costly
  463                          * we unlock the pool to prevent stalling.
  464                          */
  465                         spin_unlock_irqrestore(&pool->lock, irq_flags);
  466 
  467                         ttm_dma_pages_put(pool, &d_pages, pages_to_free,
  468                                           freed_pages);
  469 
  470                         INIT_LIST_HEAD(&d_pages);
  471 
  472                         if (likely(nr_free != FREE_ALL_PAGES))
  473                                 nr_free -= freed_pages;
  474 
  475                         if (NUM_PAGES_TO_ALLOC >= nr_free)
  476                                 npages_to_free = nr_free;
  477                         else
  478                                 npages_to_free = NUM_PAGES_TO_ALLOC;
  479 
  480                         freed_pages = 0;
  481 
  482                         /* free all so restart the processing */
  483                         if (nr_free)
  484                                 goto restart;
  485 
  486                         /* Not allowed to fall through or break because
  487                          * following context is inside spinlock while we are
  488                          * outside here.
  489                          */
  490                         goto out;
  491 
  492                 }
  493         }
  494 
  495         /* remove range of pages from the pool */
  496         if (freed_pages) {
  497                 ttm_pool_update_free_locked(pool, freed_pages);
  498                 nr_free -= freed_pages;
  499         }
  500 
  501         spin_unlock_irqrestore(&pool->lock, irq_flags);
  502 
  503         if (freed_pages)
  504                 ttm_dma_pages_put(pool, &d_pages, pages_to_free, freed_pages);
  505 out:
  506         kfree(pages_to_free);
  507         return nr_free;
  508 }
  509 
  510 static void ttm_dma_free_pool(struct device *dev, enum pool_type type)
  511 {
  512         struct device_pools *p;
  513         struct dma_pool *pool;
  514 
  515         if (!dev)
  516                 return;
  517 
  518         mutex_lock(&_manager->lock);
  519         list_for_each_entry_reverse(p, &_manager->pools, pools) {
  520                 if (p->dev != dev)
  521                         continue;
  522                 pool = p->pool;
  523                 if (pool->type != type)
  524                         continue;
  525 
  526                 list_del(&p->pools);
  527                 kfree(p);
  528                 _manager->npools--;
  529                 break;
  530         }
  531         list_for_each_entry_reverse(pool, &dev->dma_pools, pools) {
  532                 if (pool->type != type)
  533                         continue;
  534                 /* Takes a spinlock.. */
  535                 ttm_dma_page_pool_free(pool, FREE_ALL_PAGES);
  536                 WARN_ON(((pool->npages_in_use + pool->npages_free) != 0));
  537                 /* This code path is called after _all_ references to the
  538                  * struct device has been dropped - so nobody should be
  539                  * touching it. In case somebody is trying to _add_ we are
  540                  * guarded by the mutex. */
  541                 list_del(&pool->pools);
  542                 kfree(pool);
  543                 break;
  544         }
  545         mutex_unlock(&_manager->lock);
  546 }
  547 
  548 /*
  549  * On free-ing of the 'struct device' this deconstructor is run.
  550  * Albeit the pool might have already been freed earlier.
  551  */
  552 static void ttm_dma_pool_release(struct device *dev, void *res)
  553 {
  554         struct dma_pool *pool = *(struct dma_pool **)res;
  555 
  556         if (pool)
  557                 ttm_dma_free_pool(dev, pool->type);
  558 }
  559 
  560 static int ttm_dma_pool_match(struct device *dev, void *res, void *match_data)
  561 {
  562         return *(struct dma_pool **)res == match_data;
  563 }
  564 
  565 static struct dma_pool *ttm_dma_pool_init(struct device *dev, gfp_t flags,
  566                                           enum pool_type type)
  567 {
  568         char *n[] = {"wc", "uc", "cached", " dma32", "unknown",};
  569         enum pool_type t[] = {IS_WC, IS_UC, IS_CACHED, IS_DMA32, IS_UNDEFINED};
  570         struct device_pools *sec_pool = NULL;
  571         struct dma_pool *pool = NULL, **ptr;
  572         unsigned i;
  573         int ret = -ENODEV;
  574         char *p;
  575 
  576         if (!dev)
  577                 return NULL;
  578 
  579         ptr = devres_alloc(ttm_dma_pool_release, sizeof(*ptr), GFP_KERNEL);
  580         if (!ptr)
  581                 return NULL;
  582 
  583         ret = -ENOMEM;
  584 
  585         pool = kmalloc_node(sizeof(struct dma_pool), GFP_KERNEL,
  586                             dev_to_node(dev));
  587         if (!pool)
  588                 goto err_mem;
  589 
  590         sec_pool = kmalloc_node(sizeof(struct device_pools), GFP_KERNEL,
  591                                 dev_to_node(dev));
  592         if (!sec_pool)
  593                 goto err_mem;
  594 
  595         INIT_LIST_HEAD(&sec_pool->pools);
  596         sec_pool->dev = dev;
  597         sec_pool->pool =  pool;
  598 
  599         INIT_LIST_HEAD(&pool->free_list);
  600         INIT_LIST_HEAD(&pool->inuse_list);
  601         INIT_LIST_HEAD(&pool->pools);
  602         spin_lock_init(&pool->lock);
  603         pool->dev = dev;
  604         pool->npages_free = pool->npages_in_use = 0;
  605         pool->nfrees = 0;
  606         pool->gfp_flags = flags;
  607         pool->size = PAGE_SIZE;
  608         pool->type = type;
  609         pool->nrefills = 0;
  610         p = pool->name;
  611         for (i = 0; i < 5; i++) {
  612                 if (type & t[i]) {
  613                         p += snprintf(p, sizeof(pool->name) - (p - pool->name),
  614                                       "%s", n[i]);
  615                 }
  616         }
  617         *p = 0;
  618         /* We copy the name for pr_ calls b/c when dma_pool_destroy is called
  619          * - the kobj->name has already been deallocated.*/
  620         snprintf(pool->dev_name, sizeof(pool->dev_name), "%s %s",
  621                  dev_driver_string(dev), dev_name(dev));
  622         mutex_lock(&_manager->lock);
  623         /* You can get the dma_pool from either the global: */
  624         list_add(&sec_pool->pools, &_manager->pools);
  625         _manager->npools++;
  626         /* or from 'struct device': */
  627         list_add(&pool->pools, &dev->dma_pools);
  628         mutex_unlock(&_manager->lock);
  629 
  630         *ptr = pool;
  631         devres_add(dev, ptr);
  632 
  633         return pool;
  634 err_mem:
  635         devres_free(ptr);
  636         kfree(sec_pool);
  637         kfree(pool);
  638         return ERR_PTR(ret);
  639 }
  640 
  641 static struct dma_pool *ttm_dma_find_pool(struct device *dev,
  642                                           enum pool_type type)
  643 {
  644         struct dma_pool *pool, *tmp, *found = NULL;
  645 
  646         if (type == IS_UNDEFINED)
  647                 return found;
  648 
  649         /* NB: We iterate on the 'struct dev' which has no spinlock, but
  650          * it does have a kref which we have taken. The kref is taken during
  651          * graphic driver loading - in the drm_pci_init it calls either
  652          * pci_dev_get or pci_register_driver which both end up taking a kref
  653          * on 'struct device'.
  654          *
  655          * On teardown, the graphic drivers end up quiescing the TTM (put_pages)
  656          * and calls the dev_res deconstructors: ttm_dma_pool_release. The nice
  657          * thing is at that point of time there are no pages associated with the
  658          * driver so this function will not be called.
  659          */
  660         list_for_each_entry_safe(pool, tmp, &dev->dma_pools, pools) {
  661                 if (pool->type != type)
  662                         continue;
  663                 found = pool;
  664                 break;
  665         }
  666         return found;
  667 }
  668 
  669 /*
  670  * Free pages the pages that failed to change the caching state. If there
  671  * are pages that have changed their caching state already put them to the
  672  * pool.
  673  */
  674 static void ttm_dma_handle_caching_state_failure(struct dma_pool *pool,
  675                                                  struct list_head *d_pages,
  676                                                  struct page **failed_pages,
  677                                                  unsigned cpages)
  678 {
  679         struct dma_page *d_page, *tmp;
  680         struct page *p;
  681         unsigned i = 0;
  682 
  683         p = failed_pages[0];
  684         if (!p)
  685                 return;
  686         /* Find the failed page. */
  687         list_for_each_entry_safe(d_page, tmp, d_pages, page_list) {
  688                 if (d_page->p != p)
  689                         continue;
  690                 /* .. and then progress over the full list. */
  691                 list_del(&d_page->page_list);
  692                 __ttm_dma_free_page(pool, d_page);
  693                 if (++i < cpages)
  694                         p = failed_pages[i];
  695                 else
  696                         break;
  697         }
  698 
  699 }
  700 
  701 /*
  702  * Allocate 'count' pages, and put 'need' number of them on the
  703  * 'pages' and as well on the 'dma_address' starting at 'dma_offset' offset.
  704  * The full list of pages should also be on 'd_pages'.
  705  * We return zero for success, and negative numbers as errors.
  706  */
  707 static int ttm_dma_pool_alloc_new_pages(struct dma_pool *pool,
  708                                         struct list_head *d_pages,
  709                                         unsigned count)
  710 {
  711         struct page **caching_array;
  712         struct dma_page *dma_p;
  713         struct page *p;
  714         int r = 0;
  715         unsigned i, cpages;
  716         unsigned max_cpages = min(count,
  717                         (unsigned)(PAGE_SIZE/sizeof(struct page *)));
  718 
  719         /* allocate array for page caching change */
  720         caching_array = kmalloc(max_cpages*sizeof(struct page *), GFP_KERNEL);
  721 
  722         if (!caching_array) {
  723                 pr_err("%s: Unable to allocate table for new pages\n",
  724                        pool->dev_name);
  725                 return -ENOMEM;
  726         }
  727 
  728         if (count > 1) {
  729                 pr_debug("%s: (%s:%d) Getting %d pages\n",
  730                          pool->dev_name, pool->name, current->pid, count);
  731         }
  732 
  733         for (i = 0, cpages = 0; i < count; ++i) {
  734                 dma_p = __ttm_dma_alloc_page(pool);
  735                 if (!dma_p) {
  736                         pr_err("%s: Unable to get page %u\n",
  737                                pool->dev_name, i);
  738 
  739                         /* store already allocated pages in the pool after
  740                          * setting the caching state */
  741                         if (cpages) {
  742                                 r = ttm_set_pages_caching(pool, caching_array,
  743                                                           cpages);
  744                                 if (r)
  745                                         ttm_dma_handle_caching_state_failure(
  746                                                 pool, d_pages, caching_array,
  747                                                 cpages);
  748                         }
  749                         r = -ENOMEM;
  750                         goto out;
  751                 }
  752                 p = dma_p->p;
  753 #ifdef CONFIG_HIGHMEM
  754                 /* gfp flags of highmem page should never be dma32 so we
  755                  * we should be fine in such case
  756                  */
  757                 if (!PageHighMem(p))
  758 #endif
  759                 {
  760                         caching_array[cpages++] = p;
  761                         if (cpages == max_cpages) {
  762                                 /* Note: Cannot hold the spinlock */
  763                                 r = ttm_set_pages_caching(pool, caching_array,
  764                                                  cpages);
  765                                 if (r) {
  766                                         ttm_dma_handle_caching_state_failure(
  767                                                 pool, d_pages, caching_array,
  768                                                 cpages);
  769                                         goto out;
  770                                 }
  771                                 cpages = 0;
  772                         }
  773                 }
  774                 list_add(&dma_p->page_list, d_pages);
  775         }
  776 
  777         if (cpages) {
  778                 r = ttm_set_pages_caching(pool, caching_array, cpages);
  779                 if (r)
  780                         ttm_dma_handle_caching_state_failure(pool, d_pages,
  781                                         caching_array, cpages);
  782         }
  783 out:
  784         kfree(caching_array);
  785         return r;
  786 }
  787 
  788 /*
  789  * @return count of pages still required to fulfill the request.
  790  */
  791 static int ttm_dma_page_pool_fill_locked(struct dma_pool *pool,
  792                                          unsigned long *irq_flags)
  793 {
  794         unsigned count = _manager->options.small;
  795         int r = pool->npages_free;
  796 
  797         if (count > pool->npages_free) {
  798                 struct list_head d_pages;
  799 
  800                 INIT_LIST_HEAD(&d_pages);
  801 
  802                 spin_unlock_irqrestore(&pool->lock, *irq_flags);
  803 
  804                 /* Returns how many more are necessary to fulfill the
  805                  * request. */
  806                 r = ttm_dma_pool_alloc_new_pages(pool, &d_pages, count);
  807 
  808                 spin_lock_irqsave(&pool->lock, *irq_flags);
  809                 if (!r) {
  810                         /* Add the fresh to the end.. */
  811                         list_splice(&d_pages, &pool->free_list);
  812                         ++pool->nrefills;
  813                         pool->npages_free += count;
  814                         r = count;
  815                 } else {
  816                         struct dma_page *d_page;
  817                         unsigned cpages = 0;
  818 
  819                         pr_err("%s: Failed to fill %s pool (r:%d)!\n",
  820                                pool->dev_name, pool->name, r);
  821 
  822                         list_for_each_entry(d_page, &d_pages, page_list) {
  823                                 cpages++;
  824                         }
  825                         list_splice_tail(&d_pages, &pool->free_list);
  826                         pool->npages_free += cpages;
  827                         r = cpages;
  828                 }
  829         }
  830         return r;
  831 }
  832 
  833 /*
  834  * @return count of pages still required to fulfill the request.
  835  * The populate list is actually a stack (not that is matters as TTM
  836  * allocates one page at a time.
  837  */
  838 static int ttm_dma_pool_get_pages(struct dma_pool *pool,
  839                                   struct ttm_dma_tt *ttm_dma,
  840                                   unsigned index)
  841 {
  842         struct dma_page *d_page;
  843         struct ttm_tt *ttm = &ttm_dma->ttm;
  844         unsigned long irq_flags;
  845         int count, r = -ENOMEM;
  846 
  847         spin_lock_irqsave(&pool->lock, irq_flags);
  848         count = ttm_dma_page_pool_fill_locked(pool, &irq_flags);
  849         if (count) {
  850                 d_page = list_first_entry(&pool->free_list, struct dma_page, page_list);
  851                 ttm->pages[index] = d_page->p;
  852                 ttm_dma->dma_address[index] = d_page->dma;
  853                 list_move_tail(&d_page->page_list, &ttm_dma->pages_list);
  854                 r = 0;
  855                 pool->npages_in_use += 1;
  856                 pool->npages_free -= 1;
  857         }
  858         spin_unlock_irqrestore(&pool->lock, irq_flags);
  859         return r;
  860 }
  861 
  862 /*
  863  * On success pages list will hold count number of correctly
  864  * cached pages. On failure will hold the negative return value (-ENOMEM, etc).
  865  */
  866 int ttm_dma_populate(struct ttm_dma_tt *ttm_dma, struct device *dev)
  867 {
  868         struct ttm_tt *ttm = &ttm_dma->ttm;
  869         struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
  870         struct dma_pool *pool;
  871         enum pool_type type;
  872         unsigned i;
  873         gfp_t gfp_flags;
  874         int ret;
  875 
  876         if (ttm->state != tt_unpopulated)
  877                 return 0;
  878 
  879         type = ttm_to_type(ttm->page_flags, ttm->caching_state);
  880         if (ttm->page_flags & TTM_PAGE_FLAG_DMA32)
  881                 gfp_flags = GFP_USER | GFP_DMA32;
  882         else
  883                 gfp_flags = GFP_HIGHUSER;
  884         if (ttm->page_flags & TTM_PAGE_FLAG_ZERO_ALLOC)
  885                 gfp_flags |= __GFP_ZERO;
  886 
  887         pool = ttm_dma_find_pool(dev, type);
  888         if (!pool) {
  889                 pool = ttm_dma_pool_init(dev, gfp_flags, type);
  890                 if (IS_ERR_OR_NULL(pool)) {
  891                         return -ENOMEM;
  892                 }
  893         }
  894 
  895         INIT_LIST_HEAD(&ttm_dma->pages_list);
  896         for (i = 0; i < ttm->num_pages; ++i) {
  897                 ret = ttm_dma_pool_get_pages(pool, ttm_dma, i);
  898                 if (ret != 0) {
  899                         ttm_dma_unpopulate(ttm_dma, dev);
  900                         return -ENOMEM;
  901                 }
  902 
  903                 ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
  904                                                 false, false);
  905                 if (unlikely(ret != 0)) {
  906                         ttm_dma_unpopulate(ttm_dma, dev);
  907                         return -ENOMEM;
  908                 }
  909         }
  910 
  911         if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
  912                 ret = ttm_tt_swapin(ttm);
  913                 if (unlikely(ret != 0)) {
  914                         ttm_dma_unpopulate(ttm_dma, dev);
  915                         return ret;
  916                 }
  917         }
  918 
  919         ttm->state = tt_unbound;
  920         return 0;
  921 }
  922 EXPORT_SYMBOL_GPL(ttm_dma_populate);
  923 
  924 /* Get good estimation how many pages are free in pools */
  925 static int ttm_dma_pool_get_num_unused_pages(void)
  926 {
  927         struct device_pools *p;
  928         unsigned total = 0;
  929 
  930         mutex_lock(&_manager->lock);
  931         list_for_each_entry(p, &_manager->pools, pools)
  932                 total += p->pool->npages_free;
  933         mutex_unlock(&_manager->lock);
  934         return total;
  935 }
  936 
  937 /* Put all pages in pages list to correct pool to wait for reuse */
  938 void ttm_dma_unpopulate(struct ttm_dma_tt *ttm_dma, struct device *dev)
  939 {
  940         struct ttm_tt *ttm = &ttm_dma->ttm;
  941         struct dma_pool *pool;
  942         struct dma_page *d_page, *next;
  943         enum pool_type type;
  944         bool is_cached = false;
  945         unsigned count = 0, i, npages = 0;
  946         unsigned long irq_flags;
  947 
  948         type = ttm_to_type(ttm->page_flags, ttm->caching_state);
  949         pool = ttm_dma_find_pool(dev, type);
  950         if (!pool)
  951                 return;
  952 
  953         is_cached = (ttm_dma_find_pool(pool->dev,
  954                      ttm_to_type(ttm->page_flags, tt_cached)) == pool);
  955 
  956         /* make sure pages array match list and count number of pages */
  957         list_for_each_entry(d_page, &ttm_dma->pages_list, page_list) {
  958                 ttm->pages[count] = d_page->p;
  959                 count++;
  960         }
  961 
  962         spin_lock_irqsave(&pool->lock, irq_flags);
  963         pool->npages_in_use -= count;
  964         if (is_cached) {
  965                 pool->nfrees += count;
  966         } else {
  967                 pool->npages_free += count;
  968                 list_splice(&ttm_dma->pages_list, &pool->free_list);
  969                 npages = count;
  970                 if (pool->npages_free > _manager->options.max_size) {
  971                         npages = pool->npages_free - _manager->options.max_size;
  972                         /* free at least NUM_PAGES_TO_ALLOC number of pages
  973                          * to reduce calls to set_memory_wb */
  974                         if (npages < NUM_PAGES_TO_ALLOC)
  975                                 npages = NUM_PAGES_TO_ALLOC;
  976                 }
  977         }
  978         spin_unlock_irqrestore(&pool->lock, irq_flags);
  979 
  980         if (is_cached) {
  981                 list_for_each_entry_safe(d_page, next, &ttm_dma->pages_list, page_list) {
  982                         ttm_mem_global_free_page(ttm->glob->mem_glob,
  983                                                  d_page->p);
  984                         ttm_dma_page_put(pool, d_page);
  985                 }
  986         } else {
  987                 for (i = 0; i < count; i++) {
  988                         ttm_mem_global_free_page(ttm->glob->mem_glob,
  989                                                  ttm->pages[i]);
  990                 }
  991         }
  992 
  993         INIT_LIST_HEAD(&ttm_dma->pages_list);
  994         for (i = 0; i < ttm->num_pages; i++) {
  995                 ttm->pages[i] = NULL;
  996                 ttm_dma->dma_address[i] = 0;
  997         }
  998 
  999         /* shrink pool if necessary (only on !is_cached pools)*/
 1000         if (npages)
 1001                 ttm_dma_page_pool_free(pool, npages);
 1002         ttm->state = tt_unpopulated;
 1003 }
 1004 EXPORT_SYMBOL_GPL(ttm_dma_unpopulate);
 1005 
 1006 /**
 1007  * Callback for mm to request pool to reduce number of page held.
 1008  */
 1009 static int ttm_dma_pool_mm_shrink(struct shrinker *shrink,
 1010                                   struct shrink_control *sc)
 1011 {
 1012         static atomic_t start_pool = ATOMIC_INIT(0);
 1013         unsigned idx = 0;
 1014         unsigned pool_offset = atomic_add_return(1, &start_pool);
 1015         unsigned shrink_pages = sc->nr_to_scan;
 1016         struct device_pools *p;
 1017 
 1018         if (list_empty(&_manager->pools))
 1019                 return 0;
 1020 
 1021         mutex_lock(&_manager->lock);
 1022         pool_offset = pool_offset % _manager->npools;
 1023         list_for_each_entry(p, &_manager->pools, pools) {
 1024                 unsigned nr_free;
 1025 
 1026                 if (!p->dev)
 1027                         continue;
 1028                 if (shrink_pages == 0)
 1029                         break;
 1030                 /* Do it in round-robin fashion. */
 1031                 if (++idx < pool_offset)
 1032                         continue;
 1033                 nr_free = shrink_pages;
 1034                 shrink_pages = ttm_dma_page_pool_free(p->pool, nr_free);
 1035                 pr_debug("%s: (%s:%d) Asked to shrink %d, have %d more to go\n",
 1036                          p->pool->dev_name, p->pool->name, current->pid,
 1037                          nr_free, shrink_pages);
 1038         }
 1039         mutex_unlock(&_manager->lock);
 1040         /* return estimated number of unused pages in pool */
 1041         return ttm_dma_pool_get_num_unused_pages();
 1042 }
 1043 
 1044 static void ttm_dma_pool_mm_shrink_init(struct ttm_pool_manager *manager)
 1045 {
 1046         manager->mm_shrink.shrink = &ttm_dma_pool_mm_shrink;
 1047         manager->mm_shrink.seeks = 1;
 1048         register_shrinker(&manager->mm_shrink);
 1049 }
 1050 
 1051 static void ttm_dma_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
 1052 {
 1053         unregister_shrinker(&manager->mm_shrink);
 1054 }
 1055 
 1056 int ttm_dma_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 1057 {
 1058         int ret = -ENOMEM;
 1059 
 1060         WARN_ON(_manager);
 1061 
 1062         pr_info("Initializing DMA pool allocator\n");
 1063 
 1064         _manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
 1065         if (!_manager)
 1066                 goto err;
 1067 
 1068         mutex_init(&_manager->lock);
 1069         INIT_LIST_HEAD(&_manager->pools);
 1070 
 1071         _manager->options.max_size = max_pages;
 1072         _manager->options.small = SMALL_ALLOCATION;
 1073         _manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
 1074 
 1075         /* This takes care of auto-freeing the _manager */
 1076         ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
 1077                                    &glob->kobj, "dma_pool");
 1078         if (unlikely(ret != 0)) {
 1079                 kobject_put(&_manager->kobj);
 1080                 goto err;
 1081         }
 1082         ttm_dma_pool_mm_shrink_init(_manager);
 1083         return 0;
 1084 err:
 1085         return ret;
 1086 }
 1087 
 1088 void ttm_dma_page_alloc_fini(void)
 1089 {
 1090         struct device_pools *p, *t;
 1091 
 1092         pr_info("Finalizing DMA pool allocator\n");
 1093         ttm_dma_pool_mm_shrink_fini(_manager);
 1094 
 1095         list_for_each_entry_safe_reverse(p, t, &_manager->pools, pools) {
 1096                 dev_dbg(p->dev, "(%s:%d) Freeing.\n", p->pool->name,
 1097                         current->pid);
 1098                 WARN_ON(devres_destroy(p->dev, ttm_dma_pool_release,
 1099                         ttm_dma_pool_match, p->pool));
 1100                 ttm_dma_free_pool(p->dev, p->pool->type);
 1101         }
 1102         kobject_put(&_manager->kobj);
 1103         _manager = NULL;
 1104 }
 1105 
 1106 int ttm_dma_page_alloc_debugfs(struct seq_file *m, void *data)
 1107 {
 1108         struct device_pools *p;
 1109         struct dma_pool *pool = NULL;
 1110         char *h[] = {"pool", "refills", "pages freed", "inuse", "available",
 1111                      "name", "virt", "busaddr"};
 1112 
 1113         if (!_manager) {
 1114                 seq_printf(m, "No pool allocator running.\n");
 1115                 return 0;
 1116         }
 1117         seq_printf(m, "%13s %12s %13s %8s %8s %8s\n",
 1118                    h[0], h[1], h[2], h[3], h[4], h[5]);
 1119         mutex_lock(&_manager->lock);
 1120         list_for_each_entry(p, &_manager->pools, pools) {
 1121                 struct device *dev = p->dev;
 1122                 if (!dev)
 1123                         continue;
 1124                 pool = p->pool;
 1125                 seq_printf(m, "%13s %12ld %13ld %8d %8d %8s\n",
 1126                                 pool->name, pool->nrefills,
 1127                                 pool->nfrees, pool->npages_in_use,
 1128                                 pool->npages_free,
 1129                                 pool->dev_name);
 1130         }
 1131         mutex_unlock(&_manager->lock);
 1132         return 0;
 1133 }
 1134 EXPORT_SYMBOL_GPL(ttm_dma_page_alloc_debugfs);

Cache object: 2b16694e25220cf3714675f43eb986af


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