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![Paul Gortmaker](/assets/img/avatar_default.png)
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map them onto including export.h -- or if the file isn't even using those, then just delete the include. Fix up any implicit include dependencies that were being masked by module.h along the way. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
402 lines
11 KiB
C
402 lines
11 KiB
C
/*
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* Basic general purpose allocator for managing special purpose
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* memory, for example, memory that is not managed by the regular
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* kmalloc/kfree interface. Uses for this includes on-device special
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* memory, uncached memory etc.
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*
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* It is safe to use the allocator in NMI handlers and other special
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* unblockable contexts that could otherwise deadlock on locks. This
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* is implemented by using atomic operations and retries on any
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* conflicts. The disadvantage is that there may be livelocks in
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* extreme cases. For better scalability, one allocator can be used
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* for each CPU.
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*
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* The lockless operation only works if there is enough memory
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* available. If new memory is added to the pool a lock has to be
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* still taken. So any user relying on locklessness has to ensure
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* that sufficient memory is preallocated.
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*
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* The basic atomic operation of this allocator is cmpxchg on long.
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* On architectures that don't have NMI-safe cmpxchg implementation,
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* the allocator can NOT be used in NMI handler. So code uses the
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* allocator in NMI handler should depend on
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* CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
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*
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* Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/bitmap.h>
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#include <linux/rculist.h>
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#include <linux/interrupt.h>
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#include <linux/genalloc.h>
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static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
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{
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unsigned long val, nval;
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nval = *addr;
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do {
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val = nval;
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if (val & mask_to_set)
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return -EBUSY;
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cpu_relax();
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} while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
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return 0;
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}
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static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
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{
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unsigned long val, nval;
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nval = *addr;
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do {
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val = nval;
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if ((val & mask_to_clear) != mask_to_clear)
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return -EBUSY;
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cpu_relax();
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} while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
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return 0;
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}
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/*
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* bitmap_set_ll - set the specified number of bits at the specified position
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* @map: pointer to a bitmap
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* @start: a bit position in @map
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* @nr: number of bits to set
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*
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* Set @nr bits start from @start in @map lock-lessly. Several users
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* can set/clear the same bitmap simultaneously without lock. If two
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* users set the same bit, one user will return remain bits, otherwise
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* return 0.
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*/
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static int bitmap_set_ll(unsigned long *map, int start, int nr)
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{
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unsigned long *p = map + BIT_WORD(start);
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const int size = start + nr;
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int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
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unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
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while (nr - bits_to_set >= 0) {
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if (set_bits_ll(p, mask_to_set))
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return nr;
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nr -= bits_to_set;
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bits_to_set = BITS_PER_LONG;
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mask_to_set = ~0UL;
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p++;
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}
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if (nr) {
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mask_to_set &= BITMAP_LAST_WORD_MASK(size);
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if (set_bits_ll(p, mask_to_set))
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return nr;
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}
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return 0;
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}
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/*
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* bitmap_clear_ll - clear the specified number of bits at the specified position
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* @map: pointer to a bitmap
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* @start: a bit position in @map
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* @nr: number of bits to set
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*
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* Clear @nr bits start from @start in @map lock-lessly. Several users
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* can set/clear the same bitmap simultaneously without lock. If two
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* users clear the same bit, one user will return remain bits,
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* otherwise return 0.
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*/
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static int bitmap_clear_ll(unsigned long *map, int start, int nr)
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{
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unsigned long *p = map + BIT_WORD(start);
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const int size = start + nr;
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int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
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unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
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while (nr - bits_to_clear >= 0) {
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if (clear_bits_ll(p, mask_to_clear))
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return nr;
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nr -= bits_to_clear;
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bits_to_clear = BITS_PER_LONG;
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mask_to_clear = ~0UL;
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p++;
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}
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if (nr) {
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mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
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if (clear_bits_ll(p, mask_to_clear))
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return nr;
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}
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return 0;
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}
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/**
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* gen_pool_create - create a new special memory pool
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* @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
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* @nid: node id of the node the pool structure should be allocated on, or -1
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*
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* Create a new special memory pool that can be used to manage special purpose
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* memory not managed by the regular kmalloc/kfree interface.
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*/
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struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
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{
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struct gen_pool *pool;
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pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
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if (pool != NULL) {
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spin_lock_init(&pool->lock);
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INIT_LIST_HEAD(&pool->chunks);
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pool->min_alloc_order = min_alloc_order;
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}
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return pool;
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}
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EXPORT_SYMBOL(gen_pool_create);
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/**
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* gen_pool_add_virt - add a new chunk of special memory to the pool
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* @pool: pool to add new memory chunk to
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* @virt: virtual starting address of memory chunk to add to pool
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* @phys: physical starting address of memory chunk to add to pool
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* @size: size in bytes of the memory chunk to add to pool
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* @nid: node id of the node the chunk structure and bitmap should be
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* allocated on, or -1
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*
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* Add a new chunk of special memory to the specified pool.
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*
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* Returns 0 on success or a -ve errno on failure.
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*/
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int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
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size_t size, int nid)
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{
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struct gen_pool_chunk *chunk;
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int nbits = size >> pool->min_alloc_order;
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int nbytes = sizeof(struct gen_pool_chunk) +
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(nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
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chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid);
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if (unlikely(chunk == NULL))
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return -ENOMEM;
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chunk->phys_addr = phys;
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chunk->start_addr = virt;
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chunk->end_addr = virt + size;
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atomic_set(&chunk->avail, size);
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spin_lock(&pool->lock);
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list_add_rcu(&chunk->next_chunk, &pool->chunks);
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spin_unlock(&pool->lock);
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return 0;
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}
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EXPORT_SYMBOL(gen_pool_add_virt);
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/**
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* gen_pool_virt_to_phys - return the physical address of memory
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* @pool: pool to allocate from
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* @addr: starting address of memory
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*
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* Returns the physical address on success, or -1 on error.
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*/
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phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
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{
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struct gen_pool_chunk *chunk;
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phys_addr_t paddr = -1;
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rcu_read_lock();
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list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
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if (addr >= chunk->start_addr && addr < chunk->end_addr) {
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paddr = chunk->phys_addr + (addr - chunk->start_addr);
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break;
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}
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}
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rcu_read_unlock();
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return paddr;
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}
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EXPORT_SYMBOL(gen_pool_virt_to_phys);
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/**
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* gen_pool_destroy - destroy a special memory pool
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* @pool: pool to destroy
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*
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* Destroy the specified special memory pool. Verifies that there are no
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* outstanding allocations.
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*/
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void gen_pool_destroy(struct gen_pool *pool)
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{
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struct list_head *_chunk, *_next_chunk;
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struct gen_pool_chunk *chunk;
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int order = pool->min_alloc_order;
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int bit, end_bit;
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list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
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chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
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list_del(&chunk->next_chunk);
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end_bit = (chunk->end_addr - chunk->start_addr) >> order;
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bit = find_next_bit(chunk->bits, end_bit, 0);
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BUG_ON(bit < end_bit);
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kfree(chunk);
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}
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kfree(pool);
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return;
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}
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EXPORT_SYMBOL(gen_pool_destroy);
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/**
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* gen_pool_alloc - allocate special memory from the pool
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* @pool: pool to allocate from
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* @size: number of bytes to allocate from the pool
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*
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* Allocate the requested number of bytes from the specified pool.
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* Uses a first-fit algorithm. Can not be used in NMI handler on
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* architectures without NMI-safe cmpxchg implementation.
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*/
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unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
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{
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struct gen_pool_chunk *chunk;
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unsigned long addr = 0;
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int order = pool->min_alloc_order;
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int nbits, start_bit = 0, end_bit, remain;
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#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
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BUG_ON(in_nmi());
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#endif
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if (size == 0)
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return 0;
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nbits = (size + (1UL << order) - 1) >> order;
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rcu_read_lock();
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list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
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if (size > atomic_read(&chunk->avail))
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continue;
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end_bit = (chunk->end_addr - chunk->start_addr) >> order;
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retry:
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start_bit = bitmap_find_next_zero_area(chunk->bits, end_bit,
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start_bit, nbits, 0);
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if (start_bit >= end_bit)
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continue;
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remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
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if (remain) {
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remain = bitmap_clear_ll(chunk->bits, start_bit,
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nbits - remain);
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BUG_ON(remain);
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goto retry;
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}
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addr = chunk->start_addr + ((unsigned long)start_bit << order);
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size = nbits << order;
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atomic_sub(size, &chunk->avail);
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break;
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}
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rcu_read_unlock();
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return addr;
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}
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EXPORT_SYMBOL(gen_pool_alloc);
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/**
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* gen_pool_free - free allocated special memory back to the pool
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* @pool: pool to free to
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* @addr: starting address of memory to free back to pool
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* @size: size in bytes of memory to free
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*
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* Free previously allocated special memory back to the specified
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* pool. Can not be used in NMI handler on architectures without
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* NMI-safe cmpxchg implementation.
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*/
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void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
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{
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struct gen_pool_chunk *chunk;
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int order = pool->min_alloc_order;
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int start_bit, nbits, remain;
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#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
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BUG_ON(in_nmi());
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#endif
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nbits = (size + (1UL << order) - 1) >> order;
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rcu_read_lock();
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list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
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if (addr >= chunk->start_addr && addr < chunk->end_addr) {
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BUG_ON(addr + size > chunk->end_addr);
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start_bit = (addr - chunk->start_addr) >> order;
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remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
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BUG_ON(remain);
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size = nbits << order;
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atomic_add(size, &chunk->avail);
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rcu_read_unlock();
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return;
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}
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}
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rcu_read_unlock();
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BUG();
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}
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EXPORT_SYMBOL(gen_pool_free);
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/**
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* gen_pool_for_each_chunk - call func for every chunk of generic memory pool
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* @pool: the generic memory pool
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* @func: func to call
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* @data: additional data used by @func
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*
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* Call @func for every chunk of generic memory pool. The @func is
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* called with rcu_read_lock held.
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*/
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void gen_pool_for_each_chunk(struct gen_pool *pool,
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void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
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void *data)
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{
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struct gen_pool_chunk *chunk;
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rcu_read_lock();
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list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
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func(pool, chunk, data);
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rcu_read_unlock();
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}
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EXPORT_SYMBOL(gen_pool_for_each_chunk);
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/**
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* gen_pool_avail - get available free space of the pool
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* @pool: pool to get available free space
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*
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* Return available free space of the specified pool.
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*/
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size_t gen_pool_avail(struct gen_pool *pool)
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{
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struct gen_pool_chunk *chunk;
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size_t avail = 0;
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rcu_read_lock();
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list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
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avail += atomic_read(&chunk->avail);
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rcu_read_unlock();
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return avail;
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}
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EXPORT_SYMBOL_GPL(gen_pool_avail);
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/**
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* gen_pool_size - get size in bytes of memory managed by the pool
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* @pool: pool to get size
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*
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* Return size in bytes of memory managed by the pool.
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*/
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size_t gen_pool_size(struct gen_pool *pool)
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{
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struct gen_pool_chunk *chunk;
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size_t size = 0;
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rcu_read_lock();
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list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
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size += chunk->end_addr - chunk->start_addr;
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rcu_read_unlock();
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return size;
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}
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EXPORT_SYMBOL_GPL(gen_pool_size);
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