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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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/mm.h>
 #include <linux/slab.h>
 #include <linux/highmem.h>
 #include <linux/kasan.h>
 #include <linux/kmemleak.h>
 #include <linux/export.h>
 #include <linux/mempool.h>
 #include <linux/writeback.h>
 #include "slab.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 (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
         kasan_slab_free_mempool(element);
     else if (pool->alloc == mempool_alloc_pages)
         kasan_poison_pages(element, (unsigned long)pool->pool_data,
                    false);
 }
 
 static void kasan_unpoison_element(mempool_t *pool, void *element)
 {
     if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
         kasan_unpoison_range(element, __ksize(element));
     else if (pool->alloc == mempool_alloc_pages)
         kasan_unpoison_pages(element, (unsigned long)pool->pool_data,
                      false);
 }
 
 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_node(min_nr, sizeof(void *),
                         gfp_mask, node_id);
     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, NUMA_NO_NODE);
 
 }
 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, NUMA_NO_NODE);
 }
 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_node(sizeof(*pool), gfp_mask, node_id);
     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;
     wait_queue_entry_t wait;
     gfp_t gfp_temp;
 
     VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO);
     might_alloc(gfp_mask);
 
     gfp_mask |= __GFP_NOMEMALLOC;   /* don't allocate emergency reserves */
     gfp_mask |= __GFP_NORETRY;  /* don't loop in __alloc_pages */
     gfp_mask |= __GFP_NOWARN;   /* failures are OK */
 
     gfp_temp = gfp_mask & ~(__GFP_DIRECT_RECLAIM|__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();
         /*
          * Update the allocation stack trace as this is more useful
          * for debugging.
          */
         kmemleak_update_trace(element);
         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;
     }
 
     /* We must not sleep if !__GFP_DIRECT_RECLAIM */
     if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) {
         spin_unlock_irqrestore(&pool->lock, flags);
         return NULL;
     }
 
     /* Let's wait for someone else to return an element to @pool */
     init_wait(&wait);
     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;
     VM_BUG_ON(mem->ctor);
     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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