// SPDX-License-Identifier: GPL-2.0
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/*
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* ION Memory Allocator generic heap helpers
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*
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* Copyright (C) 2011 Google, Inc.
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*/
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#include <linux/err.h>
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#include <linux/freezer.h>
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#include <linux/kthread.h>
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#include <linux/mm.h>
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#include <linux/rtmutex.h>
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#include <linux/sched.h>
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#include <uapi/linux/sched/types.h>
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#include <linux/scatterlist.h>
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#include <linux/vmalloc.h>
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#include "ion_private.h"
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static unsigned long ion_heap_shrink_count(struct shrinker *shrinker,
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struct shrink_control *sc)
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{
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struct ion_heap *heap = container_of(shrinker, struct ion_heap,
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shrinker);
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int total = 0;
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total = ion_heap_freelist_size(heap) / PAGE_SIZE;
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if (heap->ops->shrink)
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total += heap->ops->shrink(heap, sc->gfp_mask, 0);
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return total;
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}
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static unsigned long ion_heap_shrink_scan(struct shrinker *shrinker,
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struct shrink_control *sc)
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{
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struct ion_heap *heap = container_of(shrinker, struct ion_heap,
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shrinker);
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int freed = 0;
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int to_scan = sc->nr_to_scan;
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if (to_scan == 0)
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return 0;
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/*
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* shrink the free list first, no point in zeroing the memory if we're
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* just going to reclaim it. Also, skip any possible page pooling.
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*/
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if (heap->flags & ION_HEAP_FLAG_DEFER_FREE)
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freed = ion_heap_freelist_shrink(heap, to_scan * PAGE_SIZE) /
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PAGE_SIZE;
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to_scan -= freed;
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if (to_scan <= 0)
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return freed;
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if (heap->ops->shrink)
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freed += heap->ops->shrink(heap, sc->gfp_mask, to_scan);
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return freed;
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}
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static size_t _ion_heap_freelist_drain(struct ion_heap *heap, size_t size,
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bool skip_pools)
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{
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struct ion_buffer *buffer;
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size_t total_drained = 0;
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if (ion_heap_freelist_size(heap) == 0)
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return 0;
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spin_lock(&heap->free_lock);
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if (size == 0)
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size = heap->free_list_size;
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while (!list_empty(&heap->free_list)) {
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if (total_drained >= size)
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break;
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buffer = list_first_entry(&heap->free_list, struct ion_buffer,
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list);
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list_del(&buffer->list);
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heap->free_list_size -= buffer->size;
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if (skip_pools)
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buffer->private_flags |= ION_PRIV_FLAG_SHRINKER_FREE;
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total_drained += buffer->size;
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spin_unlock(&heap->free_lock);
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ion_buffer_release(buffer);
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spin_lock(&heap->free_lock);
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}
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spin_unlock(&heap->free_lock);
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return total_drained;
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}
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static int ion_heap_deferred_free(void *data)
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{
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struct ion_heap *heap = data;
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while (true) {
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struct ion_buffer *buffer;
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wait_event_freezable(heap->waitqueue,
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(ion_heap_freelist_size(heap) > 0 ||
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kthread_should_stop()));
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spin_lock(&heap->free_lock);
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if (list_empty(&heap->free_list)) {
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spin_unlock(&heap->free_lock);
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if (!kthread_should_stop())
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continue;
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break;
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}
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buffer = list_first_entry(&heap->free_list, struct ion_buffer,
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list);
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list_del(&buffer->list);
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heap->free_list_size -= buffer->size;
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spin_unlock(&heap->free_lock);
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ion_buffer_release(buffer);
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}
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return 0;
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}
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void *ion_heap_map_kernel(struct ion_heap *heap,
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struct ion_buffer *buffer)
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{
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struct scatterlist *sg;
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int i, j;
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void *vaddr;
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pgprot_t pgprot;
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struct sg_table *table = buffer->sg_table;
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int npages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
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struct page **pages = vmalloc(array_size(npages,
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sizeof(struct page *)));
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struct page **tmp = pages;
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if (!pages)
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return ERR_PTR(-ENOMEM);
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if (buffer->flags & ION_FLAG_CACHED)
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pgprot = PAGE_KERNEL;
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else
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pgprot = pgprot_writecombine(PAGE_KERNEL);
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for_each_sg(table->sgl, sg, table->nents, i) {
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int npages_this_entry = PAGE_ALIGN(sg->length) / PAGE_SIZE;
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struct page *page = sg_page(sg);
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BUG_ON(i >= npages);
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for (j = 0; j < npages_this_entry; j++)
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*(tmp++) = page++;
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}
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vaddr = vmap(pages, npages, VM_MAP, pgprot);
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vfree(pages);
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if (!vaddr)
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return ERR_PTR(-ENOMEM);
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return vaddr;
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}
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EXPORT_SYMBOL_GPL(ion_heap_map_kernel);
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void ion_heap_unmap_kernel(struct ion_heap *heap,
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struct ion_buffer *buffer)
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{
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vunmap(buffer->vaddr);
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}
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EXPORT_SYMBOL_GPL(ion_heap_unmap_kernel);
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int ion_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
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struct vm_area_struct *vma)
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{
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struct sg_table *table = buffer->sg_table;
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unsigned long addr = vma->vm_start;
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unsigned long offset = vma->vm_pgoff * PAGE_SIZE;
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struct scatterlist *sg;
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int i;
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int ret;
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for_each_sg(table->sgl, sg, table->nents, i) {
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struct page *page = sg_page(sg);
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unsigned long remainder = vma->vm_end - addr;
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unsigned long len = sg->length;
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if (offset >= sg->length) {
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offset -= sg->length;
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continue;
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} else if (offset) {
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page += offset / PAGE_SIZE;
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len = sg->length - offset;
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offset = 0;
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}
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len = min(len, remainder);
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ret = remap_pfn_range(vma, addr, page_to_pfn(page), len,
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vma->vm_page_prot);
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if (ret)
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return ret;
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addr += len;
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if (addr >= vma->vm_end)
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return 0;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(ion_heap_map_user);
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void ion_heap_freelist_add(struct ion_heap *heap, struct ion_buffer *buffer)
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{
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spin_lock(&heap->free_lock);
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list_add(&buffer->list, &heap->free_list);
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heap->free_list_size += buffer->size;
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spin_unlock(&heap->free_lock);
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wake_up(&heap->waitqueue);
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}
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size_t ion_heap_freelist_size(struct ion_heap *heap)
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{
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size_t size;
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spin_lock(&heap->free_lock);
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size = heap->free_list_size;
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spin_unlock(&heap->free_lock);
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return size;
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}
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size_t ion_heap_freelist_drain(struct ion_heap *heap, size_t size)
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{
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return _ion_heap_freelist_drain(heap, size, false);
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}
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size_t ion_heap_freelist_shrink(struct ion_heap *heap, size_t size)
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{
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return _ion_heap_freelist_drain(heap, size, true);
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}
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int ion_heap_init_deferred_free(struct ion_heap *heap)
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{
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INIT_LIST_HEAD(&heap->free_list);
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init_waitqueue_head(&heap->waitqueue);
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heap->task = kthread_run(ion_heap_deferred_free, heap,
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"%s", heap->name);
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if (IS_ERR(heap->task)) {
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pr_err("%s: creating thread for deferred free failed\n",
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__func__);
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return PTR_ERR_OR_ZERO(heap->task);
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}
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sched_set_normal(heap->task, 19);
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return 0;
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}
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int ion_heap_init_shrinker(struct ion_heap *heap)
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{
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heap->shrinker.count_objects = ion_heap_shrink_count;
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heap->shrinker.scan_objects = ion_heap_shrink_scan;
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heap->shrinker.seeks = DEFAULT_SEEKS;
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heap->shrinker.batch = 0;
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return register_shrinker(&heap->shrinker);
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}
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int ion_heap_cleanup(struct ion_heap *heap)
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{
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int ret;
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if (heap->flags & ION_HEAP_FLAG_DEFER_FREE &&
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!IS_ERR_OR_NULL(heap->task)) {
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size_t free_list_size = ion_heap_freelist_size(heap);
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size_t total_drained = ion_heap_freelist_drain(heap, 0);
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if (total_drained != free_list_size) {
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pr_err("%s: %s heap drained %zu bytes, requested %zu\n",
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__func__, heap->name, free_list_size,
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total_drained);
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return -EBUSY;
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}
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ret = kthread_stop(heap->task);
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if (ret < 0) {
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pr_err("%s: failed to stop heap free thread\n",
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__func__);
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return ret;
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}
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}
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if ((heap->flags & ION_HEAP_FLAG_DEFER_FREE) || heap->ops->shrink)
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unregister_shrinker(&heap->shrinker);
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return 0;
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}
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