+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0
-/*
- * linux/mm/mempool.c
- *
- * memory buffer pool support. Such pools are mostly used
- * for guaranteed, deadlock-free memory allocations during
- * extreme VM load.
- *
- * started by Ingo Molnar, Copyright (C) 2001
- * debugging by David Rientjes, Copyright (C) 2015
- */
-
-#include <linux/slab.h>
-//#include <linux/kasan.h>
-//#include <linux/kmemleak.h>
-#include <linux/export.h>
-#include <linux/jiffies.h>
-#include <linux/mempool.h>
-#include <linux/mempool.h>
-#include <linux/sched.h>
-
-#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
-static void poison_error(mempool_t *pool, void *element, size_t size,
- size_t byte)
-{
- const int nr = pool->curr_nr;
- const int start = max_t(int, byte - (BITS_PER_LONG / 8), 0);
- const int end = min_t(int, byte + (BITS_PER_LONG / 8), size);
- int i;
-
- pr_err("BUG: mempool element poison mismatch\n");
- pr_err("Mempool %p size %zu\n", pool, size);
- pr_err(" nr=%d @ %p: %s0x", nr, element, start > 0 ? "... " : "");
- for (i = start; i < end; i++)
- pr_cont("%x ", *(u8 *)(element + i));
- pr_cont("%s\n", end < size ? "..." : "");
- dump_stack();
-}
-
-static void __check_element(mempool_t *pool, void *element, size_t size)
-{
- u8 *obj = element;
- size_t i;
-
- for (i = 0; i < size; i++) {
- u8 exp = (i < size - 1) ? POISON_FREE : POISON_END;
-
- if (obj[i] != exp) {
- poison_error(pool, element, size, i);
- return;
- }
- }
- memset(obj, POISON_INUSE, size);
-}
-
-static void check_element(mempool_t *pool, void *element)
-{
- /* Mempools backed by slab allocator */
- if (pool->free == mempool_free_slab || pool->free == mempool_kfree) {
- __check_element(pool, element, ksize(element));
- } else if (pool->free == mempool_free_pages) {
- /* Mempools backed by page allocator */
- int order = (int)(long)pool->pool_data;
- void *addr = kmap_atomic((struct page *)element);
-
- __check_element(pool, addr, 1UL << (PAGE_SHIFT + order));
- kunmap_atomic(addr);
- }
-}
-
-static void __poison_element(void *element, size_t size)
-{
- u8 *obj = element;
-
- memset(obj, POISON_FREE, size - 1);
- obj[size - 1] = POISON_END;
-}
-
-static void poison_element(mempool_t *pool, void *element)
-{
- /* Mempools backed by slab allocator */
- if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) {
- __poison_element(element, ksize(element));
- } else if (pool->alloc == mempool_alloc_pages) {
- /* Mempools backed by page allocator */
- int order = (int)(long)pool->pool_data;
- void *addr = kmap_atomic((struct page *)element);
-
- __poison_element(addr, 1UL << (PAGE_SHIFT + order));
- kunmap_atomic(addr);
- }
-}
-#else /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
-static inline void check_element(mempool_t *pool, void *element)
-{
-}
-static inline void poison_element(mempool_t *pool, void *element)
-{
-}
-#endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
-
-static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
-{
-#if 0
- if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
- kasan_poison_kfree(element, _RET_IP_);
- else if (pool->alloc == mempool_alloc_pages)
- kasan_free_pages(element, (unsigned long)pool->pool_data);
-#endif
-}
-
-static void kasan_unpoison_element(mempool_t *pool, void *element)
-{
-#if 0
- if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
- kasan_unpoison_slab(element);
- else if (pool->alloc == mempool_alloc_pages)
- kasan_alloc_pages(element, (unsigned long)pool->pool_data);
-#endif
-}
-
-static __always_inline void add_element(mempool_t *pool, void *element)
-{
- BUG_ON(pool->curr_nr >= pool->min_nr);
- poison_element(pool, element);
- kasan_poison_element(pool, element);
- pool->elements[pool->curr_nr++] = element;
-}
-
-static void *remove_element(mempool_t *pool)
-{
- void *element = pool->elements[--pool->curr_nr];
-
- BUG_ON(pool->curr_nr < 0);
- kasan_unpoison_element(pool, element);
- check_element(pool, element);
- return element;
-}
-
-/**
- * mempool_exit - exit a mempool initialized with mempool_init()
- * @pool: pointer to the memory pool which was initialized with
- * mempool_init().
- *
- * Free all reserved elements in @pool and @pool itself. This function
- * only sleeps if the free_fn() function sleeps.
- *
- * May be called on a zeroed but uninitialized mempool (i.e. allocated with
- * kzalloc()).
- */
-void mempool_exit(mempool_t *pool)
-{
- while (pool->curr_nr) {
- void *element = remove_element(pool);
- pool->free(element, pool->pool_data);
- }
- kfree(pool->elements);
- pool->elements = NULL;
-}
-EXPORT_SYMBOL(mempool_exit);
-
-/**
- * mempool_destroy - deallocate a memory pool
- * @pool: pointer to the memory pool which was allocated via
- * mempool_create().
- *
- * Free all reserved elements in @pool and @pool itself. This function
- * only sleeps if the free_fn() function sleeps.
- */
-void mempool_destroy(mempool_t *pool)
-{
- if (unlikely(!pool))
- return;
-
- mempool_exit(pool);
- kfree(pool);
-}
-EXPORT_SYMBOL(mempool_destroy);
-
-int mempool_init_node(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
- mempool_free_t *free_fn, void *pool_data,
- gfp_t gfp_mask, int node_id)
-{
- spin_lock_init(&pool->lock);
- pool->min_nr = min_nr;
- pool->pool_data = pool_data;
- pool->alloc = alloc_fn;
- pool->free = free_fn;
- init_waitqueue_head(&pool->wait);
-
- pool->elements = kmalloc_array(min_nr, sizeof(void *), gfp_mask);
- if (!pool->elements)
- return -ENOMEM;
-
- /*
- * First pre-allocate the guaranteed number of buffers.
- */
- while (pool->curr_nr < pool->min_nr) {
- void *element;
-
- element = pool->alloc(gfp_mask, pool->pool_data);
- if (unlikely(!element)) {
- mempool_exit(pool);
- return -ENOMEM;
- }
- add_element(pool, element);
- }
-
- return 0;
-}
-EXPORT_SYMBOL(mempool_init_node);
-
-/**
- * mempool_init - initialize a memory pool
- * @pool: pointer to the memory pool that should be initialized
- * @min_nr: the minimum number of elements guaranteed to be
- * allocated for this pool.
- * @alloc_fn: user-defined element-allocation function.
- * @free_fn: user-defined element-freeing function.
- * @pool_data: optional private data available to the user-defined functions.
- *
- * Like mempool_create(), but initializes the pool in (i.e. embedded in another
- * structure).
- *
- * Return: %0 on success, negative error code otherwise.
- */
-int mempool_init(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
- mempool_free_t *free_fn, void *pool_data)
-{
- return mempool_init_node(pool, min_nr, alloc_fn, free_fn,
- pool_data, GFP_KERNEL, 0);
-
-}
-EXPORT_SYMBOL(mempool_init);
-
-/**
- * mempool_create - create a memory pool
- * @min_nr: the minimum number of elements guaranteed to be
- * allocated for this pool.
- * @alloc_fn: user-defined element-allocation function.
- * @free_fn: user-defined element-freeing function.
- * @pool_data: optional private data available to the user-defined functions.
- *
- * this function creates and allocates a guaranteed size, preallocated
- * memory pool. The pool can be used from the mempool_alloc() and mempool_free()
- * functions. This function might sleep. Both the alloc_fn() and the free_fn()
- * functions might sleep - as long as the mempool_alloc() function is not called
- * from IRQ contexts.
- *
- * Return: pointer to the created memory pool object or %NULL on error.
- */
-mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
- mempool_free_t *free_fn, void *pool_data)
-{
- return mempool_create_node(min_nr,alloc_fn,free_fn, pool_data,
- GFP_KERNEL, 0);
-}
-EXPORT_SYMBOL(mempool_create);
-
-mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
- mempool_free_t *free_fn, void *pool_data,
- gfp_t gfp_mask, int node_id)
-{
- mempool_t *pool;
-
- pool = kzalloc(sizeof(*pool), gfp_mask);
- if (!pool)
- return NULL;
-
- if (mempool_init_node(pool, min_nr, alloc_fn, free_fn, pool_data,
- gfp_mask, node_id)) {
- kfree(pool);
- return NULL;
- }
-
- return pool;
-}
-EXPORT_SYMBOL(mempool_create_node);
-
-/**
- * mempool_resize - resize an existing memory pool
- * @pool: pointer to the memory pool which was allocated via
- * mempool_create().
- * @new_min_nr: the new minimum number of elements guaranteed to be
- * allocated for this pool.
- *
- * This function shrinks/grows the pool. In the case of growing,
- * it cannot be guaranteed that the pool will be grown to the new
- * size immediately, but new mempool_free() calls will refill it.
- * This function may sleep.
- *
- * Note, the caller must guarantee that no mempool_destroy is called
- * while this function is running. mempool_alloc() & mempool_free()
- * might be called (eg. from IRQ contexts) while this function executes.
- *
- * Return: %0 on success, negative error code otherwise.
- */
-int mempool_resize(mempool_t *pool, int new_min_nr)
-{
- void *element;
- void **new_elements;
- unsigned long flags;
-
- BUG_ON(new_min_nr <= 0);
- might_sleep();
-
- spin_lock_irqsave(&pool->lock, flags);
- if (new_min_nr <= pool->min_nr) {
- while (new_min_nr < pool->curr_nr) {
- element = remove_element(pool);
- spin_unlock_irqrestore(&pool->lock, flags);
- pool->free(element, pool->pool_data);
- spin_lock_irqsave(&pool->lock, flags);
- }
- pool->min_nr = new_min_nr;
- goto out_unlock;
- }
- spin_unlock_irqrestore(&pool->lock, flags);
-
- /* Grow the pool */
- new_elements = kmalloc_array(new_min_nr, sizeof(*new_elements),
- GFP_KERNEL);
- if (!new_elements)
- return -ENOMEM;
-
- spin_lock_irqsave(&pool->lock, flags);
- if (unlikely(new_min_nr <= pool->min_nr)) {
- /* Raced, other resize will do our work */
- spin_unlock_irqrestore(&pool->lock, flags);
- kfree(new_elements);
- goto out;
- }
- memcpy(new_elements, pool->elements,
- pool->curr_nr * sizeof(*new_elements));
- kfree(pool->elements);
- pool->elements = new_elements;
- pool->min_nr = new_min_nr;
-
- while (pool->curr_nr < pool->min_nr) {
- spin_unlock_irqrestore(&pool->lock, flags);
- element = pool->alloc(GFP_KERNEL, pool->pool_data);
- if (!element)
- goto out;
- spin_lock_irqsave(&pool->lock, flags);
- if (pool->curr_nr < pool->min_nr) {
- add_element(pool, element);
- } else {
- spin_unlock_irqrestore(&pool->lock, flags);
- pool->free(element, pool->pool_data); /* Raced */
- goto out;
- }
- }
-out_unlock:
- spin_unlock_irqrestore(&pool->lock, flags);
-out:
- return 0;
-}
-EXPORT_SYMBOL(mempool_resize);
-
-/**
- * mempool_alloc - allocate an element from a specific memory pool
- * @pool: pointer to the memory pool which was allocated via
- * mempool_create().
- * @gfp_mask: the usual allocation bitmask.
- *
- * this function only sleeps if the alloc_fn() function sleeps or
- * returns NULL. Note that due to preallocation, this function
- * *never* fails when called from process contexts. (it might
- * fail if called from an IRQ context.)
- * Note: using __GFP_ZERO is not supported.
- *
- * Return: pointer to the allocated element or %NULL on error.
- */
-void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
-{
- void *element;
- unsigned long flags;
- DEFINE_WAIT(wait);
- gfp_t gfp_temp;
-
- WARN_ON_ONCE(gfp_mask & __GFP_ZERO);
-
- gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */
- gfp_mask |= __GFP_NOWARN; /* failures are OK */
-
- gfp_temp = gfp_mask & ~(__GFP_IO);
-
-repeat_alloc:
-
- element = pool->alloc(gfp_temp, pool->pool_data);
- if (likely(element != NULL))
- return element;
-
- spin_lock_irqsave(&pool->lock, flags);
- if (likely(pool->curr_nr)) {
- element = remove_element(pool);
- spin_unlock_irqrestore(&pool->lock, flags);
- /* paired with rmb in mempool_free(), read comment there */
- smp_wmb();
- return element;
- }
-
- /*
- * We use gfp mask w/o direct reclaim or IO for the first round. If
- * alloc failed with that and @pool was empty, retry immediately.
- */
- if (gfp_temp != gfp_mask) {
- spin_unlock_irqrestore(&pool->lock, flags);
- gfp_temp = gfp_mask;
- goto repeat_alloc;
- }
-
- /* Let's wait for someone else to return an element to @pool */
- prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
-
- spin_unlock_irqrestore(&pool->lock, flags);
-
- /*
- * FIXME: this should be io_schedule(). The timeout is there as a
- * workaround for some DM problems in 2.6.18.
- */
- io_schedule_timeout(5*HZ);
-
- finish_wait(&pool->wait, &wait);
- goto repeat_alloc;
-}
-EXPORT_SYMBOL(mempool_alloc);
-
-/**
- * mempool_free - return an element to the pool.
- * @element: pool element pointer.
- * @pool: pointer to the memory pool which was allocated via
- * mempool_create().
- *
- * this function only sleeps if the free_fn() function sleeps.
- */
-void mempool_free(void *element, mempool_t *pool)
-{
- unsigned long flags;
-
- if (unlikely(element == NULL))
- return;
-
- /*
- * Paired with the wmb in mempool_alloc(). The preceding read is
- * for @element and the following @pool->curr_nr. This ensures
- * that the visible value of @pool->curr_nr is from after the
- * allocation of @element. This is necessary for fringe cases
- * where @element was passed to this task without going through
- * barriers.
- *
- * For example, assume @p is %NULL at the beginning and one task
- * performs "p = mempool_alloc(...);" while another task is doing
- * "while (!p) cpu_relax(); mempool_free(p, ...);". This function
- * may end up using curr_nr value which is from before allocation
- * of @p without the following rmb.
- */
- smp_rmb();
-
- /*
- * For correctness, we need a test which is guaranteed to trigger
- * if curr_nr + #allocated == min_nr. Testing curr_nr < min_nr
- * without locking achieves that and refilling as soon as possible
- * is desirable.
- *
- * Because curr_nr visible here is always a value after the
- * allocation of @element, any task which decremented curr_nr below
- * min_nr is guaranteed to see curr_nr < min_nr unless curr_nr gets
- * incremented to min_nr afterwards. If curr_nr gets incremented
- * to min_nr after the allocation of @element, the elements
- * allocated after that are subject to the same guarantee.
- *
- * Waiters happen iff curr_nr is 0 and the above guarantee also
- * ensures that there will be frees which return elements to the
- * pool waking up the waiters.
- */
- if (unlikely(READ_ONCE(pool->curr_nr) < pool->min_nr)) {
- spin_lock_irqsave(&pool->lock, flags);
- if (likely(pool->curr_nr < pool->min_nr)) {
- add_element(pool, element);
- spin_unlock_irqrestore(&pool->lock, flags);
- wake_up(&pool->wait);
- return;
- }
- spin_unlock_irqrestore(&pool->lock, flags);
- }
- pool->free(element, pool->pool_data);
-}
-EXPORT_SYMBOL(mempool_free);
-
-/*
- * A commonly used alloc and free fn.
- */
-void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data)
-{
- struct kmem_cache *mem = pool_data;
- return kmem_cache_alloc(mem, gfp_mask);
-}
-EXPORT_SYMBOL(mempool_alloc_slab);
-
-void mempool_free_slab(void *element, void *pool_data)
-{
- struct kmem_cache *mem = pool_data;
- kmem_cache_free(mem, element);
-}
-EXPORT_SYMBOL(mempool_free_slab);
-
-/*
- * A commonly used alloc and free fn that kmalloc/kfrees the amount of memory
- * specified by pool_data
- */
-void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
-{
- size_t size = (size_t)pool_data;
- return kmalloc(size, gfp_mask);
-}
-EXPORT_SYMBOL(mempool_kmalloc);
-
-void mempool_kfree(void *element, void *pool_data)
-{
- kfree(element);
-}
-EXPORT_SYMBOL(mempool_kfree);
-
-/*
- * A simple mempool-backed page allocator that allocates pages
- * of the order specified by pool_data.
- */
-void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data)
-{
- int order = (int)(long)pool_data;
- return alloc_pages(gfp_mask, order);
-}
-EXPORT_SYMBOL(mempool_alloc_pages);
-
-void mempool_free_pages(void *element, void *pool_data)
-{
- int order = (int)(long)pool_data;
- __free_pages(element, order);
-}
-EXPORT_SYMBOL(mempool_free_pages);
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