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![Andrew Morton](/assets/img/avatar_default.png)
mm/cma.c: In function 'cma_alloc': mm/cma.c:366: warning: 'pfn' may be used uninitialized in this function The patch actually improves the tracing a bit: if alloc_contig_range() fails, tracing will display the offending pfn rather than -1. Cc: Stefan Strogin <stefan.strogin@gmail.com> Cc: Michal Nazarewicz <mpn@google.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Cc: Thierry Reding <treding@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
460 lines
12 KiB
C
460 lines
12 KiB
C
/*
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* Contiguous Memory Allocator
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*
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* Copyright (c) 2010-2011 by Samsung Electronics.
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* Copyright IBM Corporation, 2013
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* Copyright LG Electronics Inc., 2014
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* Written by:
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* Marek Szyprowski <m.szyprowski@samsung.com>
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* Michal Nazarewicz <mina86@mina86.com>
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* Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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* Joonsoo Kim <iamjoonsoo.kim@lge.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License or (at your optional) any later version of the license.
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*/
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#define pr_fmt(fmt) "cma: " fmt
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#ifdef CONFIG_CMA_DEBUG
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#ifndef DEBUG
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# define DEBUG
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#endif
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#endif
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#define CREATE_TRACE_POINTS
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#include <linux/memblock.h>
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#include <linux/err.h>
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#include <linux/mm.h>
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#include <linux/mutex.h>
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#include <linux/sizes.h>
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#include <linux/slab.h>
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#include <linux/log2.h>
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#include <linux/cma.h>
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#include <linux/highmem.h>
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#include <linux/io.h>
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#include <trace/events/cma.h>
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#include "cma.h"
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struct cma cma_areas[MAX_CMA_AREAS];
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unsigned cma_area_count;
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static DEFINE_MUTEX(cma_mutex);
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phys_addr_t cma_get_base(const struct cma *cma)
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{
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return PFN_PHYS(cma->base_pfn);
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}
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unsigned long cma_get_size(const struct cma *cma)
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{
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return cma->count << PAGE_SHIFT;
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}
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static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
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int align_order)
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{
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if (align_order <= cma->order_per_bit)
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return 0;
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return (1UL << (align_order - cma->order_per_bit)) - 1;
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}
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/*
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* Find a PFN aligned to the specified order and return an offset represented in
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* order_per_bits.
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*/
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static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,
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int align_order)
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{
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if (align_order <= cma->order_per_bit)
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return 0;
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return (ALIGN(cma->base_pfn, (1UL << align_order))
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- cma->base_pfn) >> cma->order_per_bit;
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}
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static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma,
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unsigned long pages)
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{
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return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
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}
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static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
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unsigned int count)
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{
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unsigned long bitmap_no, bitmap_count;
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bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
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bitmap_count = cma_bitmap_pages_to_bits(cma, count);
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mutex_lock(&cma->lock);
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bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
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mutex_unlock(&cma->lock);
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}
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static int __init cma_activate_area(struct cma *cma)
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{
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int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
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unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
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unsigned i = cma->count >> pageblock_order;
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struct zone *zone;
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cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
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if (!cma->bitmap)
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return -ENOMEM;
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WARN_ON_ONCE(!pfn_valid(pfn));
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zone = page_zone(pfn_to_page(pfn));
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do {
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unsigned j;
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base_pfn = pfn;
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for (j = pageblock_nr_pages; j; --j, pfn++) {
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WARN_ON_ONCE(!pfn_valid(pfn));
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/*
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* alloc_contig_range requires the pfn range
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* specified to be in the same zone. Make this
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* simple by forcing the entire CMA resv range
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* to be in the same zone.
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*/
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if (page_zone(pfn_to_page(pfn)) != zone)
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goto err;
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}
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init_cma_reserved_pageblock(pfn_to_page(base_pfn));
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} while (--i);
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mutex_init(&cma->lock);
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#ifdef CONFIG_CMA_DEBUGFS
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INIT_HLIST_HEAD(&cma->mem_head);
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spin_lock_init(&cma->mem_head_lock);
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#endif
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return 0;
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err:
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kfree(cma->bitmap);
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cma->count = 0;
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return -EINVAL;
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}
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static int __init cma_init_reserved_areas(void)
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{
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int i;
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for (i = 0; i < cma_area_count; i++) {
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int ret = cma_activate_area(&cma_areas[i]);
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if (ret)
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return ret;
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}
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return 0;
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}
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core_initcall(cma_init_reserved_areas);
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/**
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* cma_init_reserved_mem() - create custom contiguous area from reserved memory
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* @base: Base address of the reserved area
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* @size: Size of the reserved area (in bytes),
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* @order_per_bit: Order of pages represented by one bit on bitmap.
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* @res_cma: Pointer to store the created cma region.
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*
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* This function creates custom contiguous area from already reserved memory.
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*/
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int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
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unsigned int order_per_bit,
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struct cma **res_cma)
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{
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struct cma *cma;
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phys_addr_t alignment;
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/* Sanity checks */
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if (cma_area_count == ARRAY_SIZE(cma_areas)) {
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pr_err("Not enough slots for CMA reserved regions!\n");
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return -ENOSPC;
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}
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if (!size || !memblock_is_region_reserved(base, size))
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return -EINVAL;
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/* ensure minimal alignment required by mm core */
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alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
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/* alignment should be aligned with order_per_bit */
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if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
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return -EINVAL;
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if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
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return -EINVAL;
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/*
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* Each reserved area must be initialised later, when more kernel
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* subsystems (like slab allocator) are available.
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*/
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cma = &cma_areas[cma_area_count];
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cma->base_pfn = PFN_DOWN(base);
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cma->count = size >> PAGE_SHIFT;
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cma->order_per_bit = order_per_bit;
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*res_cma = cma;
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cma_area_count++;
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totalcma_pages += (size / PAGE_SIZE);
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return 0;
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}
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/**
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* cma_declare_contiguous() - reserve custom contiguous area
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* @base: Base address of the reserved area optional, use 0 for any
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* @size: Size of the reserved area (in bytes),
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* @limit: End address of the reserved memory (optional, 0 for any).
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* @alignment: Alignment for the CMA area, should be power of 2 or zero
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* @order_per_bit: Order of pages represented by one bit on bitmap.
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* @fixed: hint about where to place the reserved area
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* @res_cma: Pointer to store the created cma region.
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*
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* This function reserves memory from early allocator. It should be
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* called by arch specific code once the early allocator (memblock or bootmem)
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* has been activated and all other subsystems have already allocated/reserved
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* memory. This function allows to create custom reserved areas.
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*
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* If @fixed is true, reserve contiguous area at exactly @base. If false,
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* reserve in range from @base to @limit.
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*/
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int __init cma_declare_contiguous(phys_addr_t base,
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phys_addr_t size, phys_addr_t limit,
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phys_addr_t alignment, unsigned int order_per_bit,
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bool fixed, struct cma **res_cma)
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{
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phys_addr_t memblock_end = memblock_end_of_DRAM();
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phys_addr_t highmem_start;
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int ret = 0;
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#ifdef CONFIG_X86
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/*
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* high_memory isn't direct mapped memory so retrieving its physical
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* address isn't appropriate. But it would be useful to check the
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* physical address of the highmem boundary so it's justifiable to get
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* the physical address from it. On x86 there is a validation check for
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* this case, so the following workaround is needed to avoid it.
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*/
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highmem_start = __pa_nodebug(high_memory);
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#else
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highmem_start = __pa(high_memory);
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#endif
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pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
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__func__, &size, &base, &limit, &alignment);
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if (cma_area_count == ARRAY_SIZE(cma_areas)) {
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pr_err("Not enough slots for CMA reserved regions!\n");
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return -ENOSPC;
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}
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if (!size)
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return -EINVAL;
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if (alignment && !is_power_of_2(alignment))
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return -EINVAL;
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/*
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* Sanitise input arguments.
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* Pages both ends in CMA area could be merged into adjacent unmovable
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* migratetype page by page allocator's buddy algorithm. In the case,
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* you couldn't get a contiguous memory, which is not what we want.
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*/
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alignment = max(alignment,
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(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
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base = ALIGN(base, alignment);
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size = ALIGN(size, alignment);
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limit &= ~(alignment - 1);
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if (!base)
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fixed = false;
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/* size should be aligned with order_per_bit */
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if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
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return -EINVAL;
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/*
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* If allocating at a fixed base the request region must not cross the
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* low/high memory boundary.
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*/
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if (fixed && base < highmem_start && base + size > highmem_start) {
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ret = -EINVAL;
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pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
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&base, &highmem_start);
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goto err;
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}
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/*
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* If the limit is unspecified or above the memblock end, its effective
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* value will be the memblock end. Set it explicitly to simplify further
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* checks.
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*/
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if (limit == 0 || limit > memblock_end)
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limit = memblock_end;
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/* Reserve memory */
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if (fixed) {
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if (memblock_is_region_reserved(base, size) ||
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memblock_reserve(base, size) < 0) {
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ret = -EBUSY;
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goto err;
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}
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} else {
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phys_addr_t addr = 0;
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/*
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* All pages in the reserved area must come from the same zone.
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* If the requested region crosses the low/high memory boundary,
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* try allocating from high memory first and fall back to low
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* memory in case of failure.
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*/
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if (base < highmem_start && limit > highmem_start) {
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addr = memblock_alloc_range(size, alignment,
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highmem_start, limit,
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MEMBLOCK_NONE);
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limit = highmem_start;
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}
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if (!addr) {
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addr = memblock_alloc_range(size, alignment, base,
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limit,
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MEMBLOCK_NONE);
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if (!addr) {
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ret = -ENOMEM;
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goto err;
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}
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}
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/*
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* kmemleak scans/reads tracked objects for pointers to other
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* objects but this address isn't mapped and accessible
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*/
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kmemleak_ignore(phys_to_virt(addr));
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base = addr;
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}
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ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
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if (ret)
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goto err;
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pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
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&base);
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return 0;
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err:
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pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
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return ret;
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}
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/**
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* cma_alloc() - allocate pages from contiguous area
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* @cma: Contiguous memory region for which the allocation is performed.
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* @count: Requested number of pages.
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* @align: Requested alignment of pages (in PAGE_SIZE order).
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*
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* This function allocates part of contiguous memory on specific
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* contiguous memory area.
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*/
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struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
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{
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unsigned long mask, offset;
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unsigned long pfn = -1;
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unsigned long start = 0;
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unsigned long bitmap_maxno, bitmap_no, bitmap_count;
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struct page *page = NULL;
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int ret;
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if (!cma || !cma->count)
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return NULL;
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pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
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count, align);
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if (!count)
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return NULL;
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mask = cma_bitmap_aligned_mask(cma, align);
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offset = cma_bitmap_aligned_offset(cma, align);
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bitmap_maxno = cma_bitmap_maxno(cma);
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bitmap_count = cma_bitmap_pages_to_bits(cma, count);
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for (;;) {
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mutex_lock(&cma->lock);
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bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
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bitmap_maxno, start, bitmap_count, mask,
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offset);
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if (bitmap_no >= bitmap_maxno) {
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mutex_unlock(&cma->lock);
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break;
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}
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bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
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/*
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* It's safe to drop the lock here. We've marked this region for
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* our exclusive use. If the migration fails we will take the
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* lock again and unmark it.
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*/
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mutex_unlock(&cma->lock);
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pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
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mutex_lock(&cma_mutex);
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ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
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mutex_unlock(&cma_mutex);
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if (ret == 0) {
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page = pfn_to_page(pfn);
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break;
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}
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cma_clear_bitmap(cma, pfn, count);
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if (ret != -EBUSY)
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break;
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pr_debug("%s(): memory range at %p is busy, retrying\n",
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__func__, pfn_to_page(pfn));
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/* try again with a bit different memory target */
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start = bitmap_no + mask + 1;
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}
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trace_cma_alloc(pfn, page, count, align);
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pr_debug("%s(): returned %p\n", __func__, page);
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return page;
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}
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/**
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* cma_release() - release allocated pages
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* @cma: Contiguous memory region for which the allocation is performed.
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* @pages: Allocated pages.
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* @count: Number of allocated pages.
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*
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* This function releases memory allocated by alloc_cma().
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* It returns false when provided pages do not belong to contiguous area and
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* true otherwise.
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*/
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bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
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{
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unsigned long pfn;
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if (!cma || !pages)
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return false;
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pr_debug("%s(page %p)\n", __func__, (void *)pages);
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pfn = page_to_pfn(pages);
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if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
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return false;
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VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
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free_contig_range(pfn, count);
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cma_clear_bitmap(cma, pfn, count);
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trace_cma_release(pfn, pages, count);
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return true;
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}
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