--- /dev/null
+/*
+ * linux/mm/percpu.c - percpu memory allocator
+ *
+ * Copyright (C) 2009 SUSE Linux Products GmbH
+ * Copyright (C) 2009 Tejun Heo <tj@kernel.org>
+ *
+ * This file is released under the GPLv2.
+ *
+ * This is percpu allocator which can handle both static and dynamic
+ * areas. Percpu areas are allocated in chunks in vmalloc area. Each
+ * chunk is consisted of num_possible_cpus() units and the first chunk
+ * is used for static percpu variables in the kernel image (special
+ * boot time alloc/init handling necessary as these areas need to be
+ * brought up before allocation services are running). Unit grows as
+ * necessary and all units grow or shrink in unison. When a chunk is
+ * filled up, another chunk is allocated. ie. in vmalloc area
+ *
+ * c0 c1 c2
+ * ------------------- ------------------- ------------
+ * | u0 | u1 | u2 | u3 | | u0 | u1 | u2 | u3 | | u0 | u1 | u
+ * ------------------- ...... ------------------- .... ------------
+ *
+ * Allocation is done in offset-size areas of single unit space. Ie,
+ * an area of 512 bytes at 6k in c1 occupies 512 bytes at 6k of c1:u0,
+ * c1:u1, c1:u2 and c1:u3. Percpu access can be done by configuring
+ * percpu base registers UNIT_SIZE apart.
+ *
+ * There are usually many small percpu allocations many of them as
+ * small as 4 bytes. The allocator organizes chunks into lists
+ * according to free size and tries to allocate from the fullest one.
+ * Each chunk keeps the maximum contiguous area size hint which is
+ * guaranteed to be eqaul to or larger than the maximum contiguous
+ * area in the chunk. This helps the allocator not to iterate the
+ * chunk maps unnecessarily.
+ *
+ * Allocation state in each chunk is kept using an array of integers
+ * on chunk->map. A positive value in the map represents a free
+ * region and negative allocated. Allocation inside a chunk is done
+ * by scanning this map sequentially and serving the first matching
+ * entry. This is mostly copied from the percpu_modalloc() allocator.
+ * Chunks are also linked into a rb tree to ease address to chunk
+ * mapping during free.
+ *
+ * To use this allocator, arch code should do the followings.
+ *
+ * - define CONFIG_HAVE_DYNAMIC_PER_CPU_AREA
+ *
+ * - define __addr_to_pcpu_ptr() and __pcpu_ptr_to_addr() to translate
+ * regular address to percpu pointer and back
+ *
+ * - use pcpu_setup_static() during percpu area initialization to
+ * setup kernel static percpu area
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bootmem.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/percpu.h>
+#include <linux/pfn.h>
+#include <linux/rbtree.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+
+#define PCPU_MIN_UNIT_PAGES_SHIFT 4 /* also max alloc size */
+#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */
+#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */
+
+struct pcpu_chunk {
+ struct list_head list; /* linked to pcpu_slot lists */
+ struct rb_node rb_node; /* key is chunk->vm->addr */
+ int free_size; /* free bytes in the chunk */
+ int contig_hint; /* max contiguous size hint */
+ struct vm_struct *vm; /* mapped vmalloc region */
+ int map_used; /* # of map entries used */
+ int map_alloc; /* # of map entries allocated */
+ int *map; /* allocation map */
+ struct page *page[]; /* #cpus * UNIT_PAGES */
+};
+
+static int pcpu_unit_pages_shift;
+static int pcpu_unit_pages;
+static int pcpu_unit_shift;
+static int pcpu_unit_size;
+static int pcpu_chunk_size;
+static int pcpu_nr_slots;
+static size_t pcpu_chunk_struct_size;
+
+/* the address of the first chunk which starts with the kernel static area */
+void *pcpu_base_addr;
+EXPORT_SYMBOL_GPL(pcpu_base_addr);
+
+/* the size of kernel static area */
+static int pcpu_static_size;
+
+/*
+ * One mutex to rule them all.
+ *
+ * The following mutex is grabbed in the outermost public alloc/free
+ * interface functions and released only when the operation is
+ * complete. As such, every function in this file other than the
+ * outermost functions are called under pcpu_mutex.
+ *
+ * It can easily be switched to use spinlock such that only the area
+ * allocation and page population commit are protected with it doing
+ * actual [de]allocation without holding any lock. However, given
+ * what this allocator does, I think it's better to let them run
+ * sequentially.
+ */
+static DEFINE_MUTEX(pcpu_mutex);
+
+static struct list_head *pcpu_slot; /* chunk list slots */
+static struct rb_root pcpu_addr_root = RB_ROOT; /* chunks by address */
+
+static int pcpu_size_to_slot(int size)
+{
+ int highbit = fls(size);
+ return max(highbit - PCPU_SLOT_BASE_SHIFT + 2, 1);
+}
+
+static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
+{
+ if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int))
+ return 0;
+
+ return pcpu_size_to_slot(chunk->free_size);
+}
+
+static int pcpu_page_idx(unsigned int cpu, int page_idx)
+{
+ return (cpu << pcpu_unit_pages_shift) + page_idx;
+}
+
+static struct page **pcpu_chunk_pagep(struct pcpu_chunk *chunk,
+ unsigned int cpu, int page_idx)
+{
+ return &chunk->page[pcpu_page_idx(cpu, page_idx)];
+}
+
+static unsigned long pcpu_chunk_addr(struct pcpu_chunk *chunk,
+ unsigned int cpu, int page_idx)
+{
+ return (unsigned long)chunk->vm->addr +
+ (pcpu_page_idx(cpu, page_idx) << PAGE_SHIFT);
+}
+
+static bool pcpu_chunk_page_occupied(struct pcpu_chunk *chunk,
+ int page_idx)
+{
+ return *pcpu_chunk_pagep(chunk, 0, page_idx) != NULL;
+}
+
+/**
+ * pcpu_realloc - versatile realloc
+ * @p: the current pointer (can be NULL for new allocations)
+ * @size: the current size (can be 0 for new allocations)
+ * @new_size: the wanted new size (can be 0 for free)
+ *
+ * More robust realloc which can be used to allocate, resize or free a
+ * memory area of arbitrary size. If the needed size goes over
+ * PAGE_SIZE, kernel VM is used.
+ *
+ * RETURNS:
+ * The new pointer on success, NULL on failure.
+ */
+static void *pcpu_realloc(void *p, size_t size, size_t new_size)
+{
+ void *new;
+
+ if (new_size <= PAGE_SIZE)
+ new = kmalloc(new_size, GFP_KERNEL);
+ else
+ new = vmalloc(new_size);
+ if (new_size && !new)
+ return NULL;
+
+ memcpy(new, p, min(size, new_size));
+ if (new_size > size)
+ memset(new + size, 0, new_size - size);
+
+ if (size <= PAGE_SIZE)
+ kfree(p);
+ else
+ vfree(p);
+
+ return new;
+}
+
+/**
+ * pcpu_chunk_relocate - put chunk in the appropriate chunk slot
+ * @chunk: chunk of interest
+ * @oslot: the previous slot it was on
+ *
+ * This function is called after an allocation or free changed @chunk.
+ * New slot according to the changed state is determined and @chunk is
+ * moved to the slot.
+ */
+static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot)
+{
+ int nslot = pcpu_chunk_slot(chunk);
+
+ if (oslot != nslot) {
+ if (oslot < nslot)
+ list_move(&chunk->list, &pcpu_slot[nslot]);
+ else
+ list_move_tail(&chunk->list, &pcpu_slot[nslot]);
+ }
+}
+
+static struct rb_node **pcpu_chunk_rb_search(void *addr,
+ struct rb_node **parentp)
+{
+ struct rb_node **p = &pcpu_addr_root.rb_node;
+ struct rb_node *parent = NULL;
+ struct pcpu_chunk *chunk;
+
+ while (*p) {
+ parent = *p;
+ chunk = rb_entry(parent, struct pcpu_chunk, rb_node);
+
+ if (addr < chunk->vm->addr)
+ p = &(*p)->rb_left;
+ else if (addr > chunk->vm->addr)
+ p = &(*p)->rb_right;
+ else
+ break;
+ }
+
+ if (parentp)
+ *parentp = parent;
+ return p;
+}
+
+/**
+ * pcpu_chunk_addr_search - search for chunk containing specified address
+ * @addr: address to search for
+ *
+ * Look for chunk which might contain @addr. More specifically, it
+ * searchs for the chunk with the highest start address which isn't
+ * beyond @addr.
+ *
+ * RETURNS:
+ * The address of the found chunk.
+ */
+static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
+{
+ struct rb_node *n, *parent;
+ struct pcpu_chunk *chunk;
+
+ n = *pcpu_chunk_rb_search(addr, &parent);
+ if (!n) {
+ /* no exactly matching chunk, the parent is the closest */
+ n = parent;
+ BUG_ON(!n);
+ }
+ chunk = rb_entry(n, struct pcpu_chunk, rb_node);
+
+ if (addr < chunk->vm->addr) {
+ /* the parent was the next one, look for the previous one */
+ n = rb_prev(n);
+ BUG_ON(!n);
+ chunk = rb_entry(n, struct pcpu_chunk, rb_node);
+ }
+
+ return chunk;
+}
+
+/**
+ * pcpu_chunk_addr_insert - insert chunk into address rb tree
+ * @new: chunk to insert
+ *
+ * Insert @new into address rb tree.
+ */
+static void pcpu_chunk_addr_insert(struct pcpu_chunk *new)
+{
+ struct rb_node **p, *parent;
+
+ p = pcpu_chunk_rb_search(new->vm->addr, &parent);
+ BUG_ON(*p);
+ rb_link_node(&new->rb_node, parent, p);
+ rb_insert_color(&new->rb_node, &pcpu_addr_root);
+}
+
+/**
+ * pcpu_split_block - split a map block
+ * @chunk: chunk of interest
+ * @i: index of map block to split
+ * @head: head size (can be 0)
+ * @tail: tail size (can be 0)
+ *
+ * Split the @i'th map block into two or three blocks. If @head is
+ * non-zero, @head bytes block is inserted before block @i moving it
+ * to @i+1 and reducing its size by @head bytes.
+ *
+ * If @tail is non-zero, the target block, which can be @i or @i+1
+ * depending on @head, is reduced by @tail bytes and @tail byte block
+ * is inserted after the target block.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+static int pcpu_split_block(struct pcpu_chunk *chunk, int i, int head, int tail)
+{
+ int nr_extra = !!head + !!tail;
+ int target = chunk->map_used + nr_extra;
+
+ /* reallocation required? */
+ if (chunk->map_alloc < target) {
+ int new_alloc = chunk->map_alloc;
+ int *new;
+
+ while (new_alloc < target)
+ new_alloc *= 2;
+
+ new = pcpu_realloc(chunk->map,
+ chunk->map_alloc * sizeof(new[0]),
+ new_alloc * sizeof(new[0]));
+ if (!new)
+ return -ENOMEM;
+
+ chunk->map_alloc = new_alloc;
+ chunk->map = new;
+ }
+
+ /* insert a new subblock */
+ memmove(&chunk->map[i + nr_extra], &chunk->map[i],
+ sizeof(chunk->map[0]) * (chunk->map_used - i));
+ chunk->map_used += nr_extra;
+
+ if (head) {
+ chunk->map[i + 1] = chunk->map[i] - head;
+ chunk->map[i++] = head;
+ }
+ if (tail) {
+ chunk->map[i++] -= tail;
+ chunk->map[i] = tail;
+ }
+ return 0;
+}
+
+/**
+ * pcpu_alloc_area - allocate area from a pcpu_chunk
+ * @chunk: chunk of interest
+ * @size: wanted size
+ * @align: wanted align
+ *
+ * Try to allocate @size bytes area aligned at @align from @chunk.
+ * Note that this function only allocates the offset. It doesn't
+ * populate or map the area.
+ *
+ * RETURNS:
+ * Allocated offset in @chunk on success, -errno on failure.
+ */
+static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align)
+{
+ int oslot = pcpu_chunk_slot(chunk);
+ int max_contig = 0;
+ int i, off;
+
+ /*
+ * The static chunk initially doesn't have map attached
+ * because kmalloc wasn't available during init. Give it one.
+ */
+ if (unlikely(!chunk->map)) {
+ chunk->map = pcpu_realloc(NULL, 0,
+ PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
+ if (!chunk->map)
+ return -ENOMEM;
+
+ chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
+ chunk->map[chunk->map_used++] = -pcpu_static_size;
+ if (chunk->free_size)
+ chunk->map[chunk->map_used++] = chunk->free_size;
+ }
+
+ for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++])) {
+ bool is_last = i + 1 == chunk->map_used;
+ int head, tail;
+
+ /* extra for alignment requirement */
+ head = ALIGN(off, align) - off;
+ BUG_ON(i == 0 && head != 0);
+
+ if (chunk->map[i] < 0)
+ continue;
+ if (chunk->map[i] < head + size) {
+ max_contig = max(chunk->map[i], max_contig);
+ continue;
+ }
+
+ /*
+ * If head is small or the previous block is free,
+ * merge'em. Note that 'small' is defined as smaller
+ * than sizeof(int), which is very small but isn't too
+ * uncommon for percpu allocations.
+ */
+ if (head && (head < sizeof(int) || chunk->map[i - 1] > 0)) {
+ if (chunk->map[i - 1] > 0)
+ chunk->map[i - 1] += head;
+ else {
+ chunk->map[i - 1] -= head;
+ chunk->free_size -= head;
+ }
+ chunk->map[i] -= head;
+ off += head;
+ head = 0;
+ }
+
+ /* if tail is small, just keep it around */
+ tail = chunk->map[i] - head - size;
+ if (tail < sizeof(int))
+ tail = 0;
+
+ /* split if warranted */
+ if (head || tail) {
+ if (pcpu_split_block(chunk, i, head, tail))
+ return -ENOMEM;
+ if (head) {
+ i++;
+ off += head;
+ max_contig = max(chunk->map[i - 1], max_contig);
+ }
+ if (tail)
+ max_contig = max(chunk->map[i + 1], max_contig);
+ }
+
+ /* update hint and mark allocated */
+ if (is_last)
+ chunk->contig_hint = max_contig; /* fully scanned */
+ else
+ chunk->contig_hint = max(chunk->contig_hint,
+ max_contig);
+
+ chunk->free_size -= chunk->map[i];
+ chunk->map[i] = -chunk->map[i];
+
+ pcpu_chunk_relocate(chunk, oslot);
+ return off;
+ }
+
+ chunk->contig_hint = max_contig; /* fully scanned */
+ pcpu_chunk_relocate(chunk, oslot);
+
+ /*
+ * Tell the upper layer that this chunk has no area left.
+ * Note that this is not an error condition but a notification
+ * to upper layer that it needs to look at other chunks.
+ * -ENOSPC is chosen as it isn't used in memory subsystem and
+ * matches the meaning in a way.
+ */
+ return -ENOSPC;
+}
+
+/**
+ * pcpu_free_area - free area to a pcpu_chunk
+ * @chunk: chunk of interest
+ * @freeme: offset of area to free
+ *
+ * Free area starting from @freeme to @chunk. Note that this function
+ * only modifies the allocation map. It doesn't depopulate or unmap
+ * the area.
+ */
+static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme)
+{
+ int oslot = pcpu_chunk_slot(chunk);
+ int i, off;
+
+ for (i = 0, off = 0; i < chunk->map_used; off += abs(chunk->map[i++]))
+ if (off == freeme)
+ break;
+ BUG_ON(off != freeme);
+ BUG_ON(chunk->map[i] > 0);
+
+ chunk->map[i] = -chunk->map[i];
+ chunk->free_size += chunk->map[i];
+
+ /* merge with previous? */
+ if (i > 0 && chunk->map[i - 1] >= 0) {
+ chunk->map[i - 1] += chunk->map[i];
+ chunk->map_used--;
+ memmove(&chunk->map[i], &chunk->map[i + 1],
+ (chunk->map_used - i) * sizeof(chunk->map[0]));
+ i--;
+ }
+ /* merge with next? */
+ if (i + 1 < chunk->map_used && chunk->map[i + 1] >= 0) {
+ chunk->map[i] += chunk->map[i + 1];
+ chunk->map_used--;
+ memmove(&chunk->map[i + 1], &chunk->map[i + 2],
+ (chunk->map_used - (i + 1)) * sizeof(chunk->map[0]));
+ }
+
+ chunk->contig_hint = max(chunk->map[i], chunk->contig_hint);
+ pcpu_chunk_relocate(chunk, oslot);
+}
+
+/**
+ * pcpu_unmap - unmap pages out of a pcpu_chunk
+ * @chunk: chunk of interest
+ * @page_start: page index of the first page to unmap
+ * @page_end: page index of the last page to unmap + 1
+ * @flush: whether to flush cache and tlb or not
+ *
+ * For each cpu, unmap pages [@page_start,@page_end) out of @chunk.
+ * If @flush is true, vcache is flushed before unmapping and tlb
+ * after.
+ */
+static void pcpu_unmap(struct pcpu_chunk *chunk, int page_start, int page_end,
+ bool flush)
+{
+ unsigned int last = num_possible_cpus() - 1;
+ unsigned int cpu;
+
+ /*
+ * Each flushing trial can be very expensive, issue flush on
+ * the whole region at once rather than doing it for each cpu.
+ * This could be an overkill but is more scalable.
+ */
+ if (flush)
+ flush_cache_vunmap(pcpu_chunk_addr(chunk, 0, page_start),
+ pcpu_chunk_addr(chunk, last, page_end));
+
+ for_each_possible_cpu(cpu)
+ unmap_kernel_range_noflush(
+ pcpu_chunk_addr(chunk, cpu, page_start),
+ (page_end - page_start) << PAGE_SHIFT);
+
+ /* ditto as flush_cache_vunmap() */
+ if (flush)
+ flush_tlb_kernel_range(pcpu_chunk_addr(chunk, 0, page_start),
+ pcpu_chunk_addr(chunk, last, page_end));
+}
+
+/**
+ * pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
+ * @chunk: chunk to depopulate
+ * @off: offset to the area to depopulate
+ * @size: size of the area to depopulate
+ * @flush: whether to flush cache and tlb or not
+ *
+ * For each cpu, depopulate and unmap pages [@page_start,@page_end)
+ * from @chunk. If @flush is true, vcache is flushed before unmapping
+ * and tlb after.
+ */
+static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, size_t off,
+ size_t size, bool flush)
+{
+ int page_start = PFN_DOWN(off);
+ int page_end = PFN_UP(off + size);
+ int unmap_start = -1;
+ int uninitialized_var(unmap_end);
+ unsigned int cpu;
+ int i;
+
+ for (i = page_start; i < page_end; i++) {
+ for_each_possible_cpu(cpu) {
+ struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
+
+ if (!*pagep)
+ continue;
+
+ __free_page(*pagep);
+
+ /*
+ * If it's partial depopulation, it might get
+ * populated or depopulated again. Mark the
+ * page gone.
+ */
+ *pagep = NULL;
+
+ unmap_start = unmap_start < 0 ? i : unmap_start;
+ unmap_end = i + 1;
+ }
+ }
+
+ if (unmap_start >= 0)
+ pcpu_unmap(chunk, unmap_start, unmap_end, flush);
+}
+
+/**
+ * pcpu_map - map pages into a pcpu_chunk
+ * @chunk: chunk of interest
+ * @page_start: page index of the first page to map
+ * @page_end: page index of the last page to map + 1
+ *
+ * For each cpu, map pages [@page_start,@page_end) into @chunk.
+ * vcache is flushed afterwards.
+ */
+static int pcpu_map(struct pcpu_chunk *chunk, int page_start, int page_end)
+{
+ unsigned int last = num_possible_cpus() - 1;
+ unsigned int cpu;
+ int err;
+
+ for_each_possible_cpu(cpu) {
+ err = map_kernel_range_noflush(
+ pcpu_chunk_addr(chunk, cpu, page_start),
+ (page_end - page_start) << PAGE_SHIFT,
+ PAGE_KERNEL,
+ pcpu_chunk_pagep(chunk, cpu, page_start));
+ if (err < 0)
+ return err;
+ }
+
+ /* flush at once, please read comments in pcpu_unmap() */
+ flush_cache_vmap(pcpu_chunk_addr(chunk, 0, page_start),
+ pcpu_chunk_addr(chunk, last, page_end));
+ return 0;
+}
+
+/**
+ * pcpu_populate_chunk - populate and map an area of a pcpu_chunk
+ * @chunk: chunk of interest
+ * @off: offset to the area to populate
+ * @size: size of the area to populate
+ *
+ * For each cpu, populate and map pages [@page_start,@page_end) into
+ * @chunk. The area is cleared on return.
+ */
+static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
+{
+ const gfp_t alloc_mask = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD;
+ int page_start = PFN_DOWN(off);
+ int page_end = PFN_UP(off + size);
+ int map_start = -1;
+ int map_end;
+ unsigned int cpu;
+ int i;
+
+ for (i = page_start; i < page_end; i++) {
+ if (pcpu_chunk_page_occupied(chunk, i)) {
+ if (map_start >= 0) {
+ if (pcpu_map(chunk, map_start, map_end))
+ goto err;
+ map_start = -1;
+ }
+ continue;
+ }
+
+ map_start = map_start < 0 ? i : map_start;
+ map_end = i + 1;
+
+ for_each_possible_cpu(cpu) {
+ struct page **pagep = pcpu_chunk_pagep(chunk, cpu, i);
+
+ *pagep = alloc_pages_node(cpu_to_node(cpu),
+ alloc_mask, 0);
+ if (!*pagep)
+ goto err;
+ }
+ }
+
+ if (map_start >= 0 && pcpu_map(chunk, map_start, map_end))
+ goto err;
+
+ for_each_possible_cpu(cpu)
+ memset(chunk->vm->addr + (cpu << pcpu_unit_shift) + off, 0,
+ size);
+
+ return 0;
+err:
+ /* likely under heavy memory pressure, give memory back */
+ pcpu_depopulate_chunk(chunk, off, size, true);
+ return -ENOMEM;
+}
+
+static void free_pcpu_chunk(struct pcpu_chunk *chunk)
+{
+ if (!chunk)
+ return;
+ if (chunk->vm)
+ free_vm_area(chunk->vm);
+ pcpu_realloc(chunk->map, chunk->map_alloc * sizeof(chunk->map[0]), 0);
+ kfree(chunk);
+}
+
+static struct pcpu_chunk *alloc_pcpu_chunk(void)
+{
+ struct pcpu_chunk *chunk;
+
+ chunk = kzalloc(pcpu_chunk_struct_size, GFP_KERNEL);
+ if (!chunk)
+ return NULL;
+
+ chunk->map = pcpu_realloc(NULL, 0,
+ PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
+ chunk->map_alloc = PCPU_DFL_MAP_ALLOC;
+ chunk->map[chunk->map_used++] = pcpu_unit_size;
+
+ chunk->vm = get_vm_area(pcpu_chunk_size, GFP_KERNEL);
+ if (!chunk->vm) {
+ free_pcpu_chunk(chunk);
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&chunk->list);
+ chunk->free_size = pcpu_unit_size;
+ chunk->contig_hint = pcpu_unit_size;
+
+ return chunk;
+}
+
+/**
+ * __alloc_percpu - allocate percpu area
+ * @size: size of area to allocate
+ * @align: alignment of area (max PAGE_SIZE)
+ *
+ * Allocate percpu area of @size bytes aligned at @align. Might
+ * sleep. Might trigger writeouts.
+ *
+ * RETURNS:
+ * Percpu pointer to the allocated area on success, NULL on failure.
+ */
+void *__alloc_percpu(size_t size, size_t align)
+{
+ void *ptr = NULL;
+ struct pcpu_chunk *chunk;
+ int slot, off;
+
+ if (unlikely(!size || size > PAGE_SIZE << PCPU_MIN_UNIT_PAGES_SHIFT ||
+ align > PAGE_SIZE)) {
+ WARN(true, "illegal size (%zu) or align (%zu) for "
+ "percpu allocation\n", size, align);
+ return NULL;
+ }
+
+ mutex_lock(&pcpu_mutex);
+
+ /* allocate area */
+ for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
+ list_for_each_entry(chunk, &pcpu_slot[slot], list) {
+ if (size > chunk->contig_hint)
+ continue;
+ off = pcpu_alloc_area(chunk, size, align);
+ if (off >= 0)
+ goto area_found;
+ if (off != -ENOSPC)
+ goto out_unlock;
+ }
+ }
+
+ /* hmmm... no space left, create a new chunk */
+ chunk = alloc_pcpu_chunk();
+ if (!chunk)
+ goto out_unlock;
+ pcpu_chunk_relocate(chunk, -1);
+ pcpu_chunk_addr_insert(chunk);
+
+ off = pcpu_alloc_area(chunk, size, align);
+ if (off < 0)
+ goto out_unlock;
+
+area_found:
+ /* populate, map and clear the area */
+ if (pcpu_populate_chunk(chunk, off, size)) {
+ pcpu_free_area(chunk, off);
+ goto out_unlock;
+ }
+
+ ptr = __addr_to_pcpu_ptr(chunk->vm->addr + off);
+out_unlock:
+ mutex_unlock(&pcpu_mutex);
+ return ptr;
+}
+EXPORT_SYMBOL_GPL(__alloc_percpu);
+
+static void pcpu_kill_chunk(struct pcpu_chunk *chunk)
+{
+ pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size, false);
+ list_del(&chunk->list);
+ rb_erase(&chunk->rb_node, &pcpu_addr_root);
+ free_pcpu_chunk(chunk);
+}
+
+/**
+ * free_percpu - free percpu area
+ * @ptr: pointer to area to free
+ *
+ * Free percpu area @ptr. Might sleep.
+ */
+void free_percpu(void *ptr)
+{
+ void *addr = __pcpu_ptr_to_addr(ptr);
+ struct pcpu_chunk *chunk;
+ int off;
+
+ if (!ptr)
+ return;
+
+ mutex_lock(&pcpu_mutex);
+
+ chunk = pcpu_chunk_addr_search(addr);
+ off = addr - chunk->vm->addr;
+
+ pcpu_free_area(chunk, off);
+
+ /* the chunk became fully free, kill one if there are other free ones */
+ if (chunk->free_size == pcpu_unit_size) {
+ struct pcpu_chunk *pos;
+
+ list_for_each_entry(pos,
+ &pcpu_slot[pcpu_chunk_slot(chunk)], list)
+ if (pos != chunk) {
+ pcpu_kill_chunk(pos);
+ break;
+ }
+ }
+
+ mutex_unlock(&pcpu_mutex);
+}
+EXPORT_SYMBOL_GPL(free_percpu);
+
+/**
+ * pcpu_setup_static - initialize kernel static percpu area
+ * @populate_pte_fn: callback to allocate pagetable
+ * @pages: num_possible_cpus() * PFN_UP(cpu_size) pages
+ *
+ * Initialize kernel static percpu area. The caller should allocate
+ * all the necessary pages and pass them in @pages.
+ * @populate_pte_fn() is called on each page to be used for percpu
+ * mapping and is responsible for making sure all the necessary page
+ * tables for the page is allocated.
+ *
+ * RETURNS:
+ * The determined pcpu_unit_size which can be used to initialize
+ * percpu access.
+ */
+size_t __init pcpu_setup_static(pcpu_populate_pte_fn_t populate_pte_fn,
+ struct page **pages, size_t cpu_size)
+{
+ static struct vm_struct static_vm;
+ struct pcpu_chunk *static_chunk;
+ int nr_cpu_pages = DIV_ROUND_UP(cpu_size, PAGE_SIZE);
+ unsigned int cpu;
+ int err, i;
+
+ pcpu_unit_pages_shift = max_t(int, PCPU_MIN_UNIT_PAGES_SHIFT,
+ order_base_2(cpu_size) - PAGE_SHIFT);
+
+ pcpu_static_size = cpu_size;
+ pcpu_unit_pages = 1 << pcpu_unit_pages_shift;
+ pcpu_unit_shift = PAGE_SHIFT + pcpu_unit_pages_shift;
+ pcpu_unit_size = 1 << pcpu_unit_shift;
+ pcpu_chunk_size = num_possible_cpus() * pcpu_unit_size;
+ pcpu_nr_slots = pcpu_size_to_slot(pcpu_unit_size) + 1;
+ pcpu_chunk_struct_size = sizeof(struct pcpu_chunk)
+ + (1 << pcpu_unit_pages_shift) * sizeof(struct page *);
+
+ /* allocate chunk slots */
+ pcpu_slot = alloc_bootmem(pcpu_nr_slots * sizeof(pcpu_slot[0]));
+ for (i = 0; i < pcpu_nr_slots; i++)
+ INIT_LIST_HEAD(&pcpu_slot[i]);
+
+ /* init and register vm area */
+ static_vm.flags = VM_ALLOC;
+ static_vm.size = pcpu_chunk_size;
+ vm_area_register_early(&static_vm);
+
+ /* init static_chunk */
+ static_chunk = alloc_bootmem(pcpu_chunk_struct_size);
+ INIT_LIST_HEAD(&static_chunk->list);
+ static_chunk->vm = &static_vm;
+ static_chunk->free_size = pcpu_unit_size - pcpu_static_size;
+ static_chunk->contig_hint = static_chunk->free_size;
+
+ /* assign pages and map them */
+ for_each_possible_cpu(cpu) {
+ for (i = 0; i < nr_cpu_pages; i++) {
+ *pcpu_chunk_pagep(static_chunk, cpu, i) = *pages++;
+ populate_pte_fn(pcpu_chunk_addr(static_chunk, cpu, i));
+ }
+ }
+
+ err = pcpu_map(static_chunk, 0, nr_cpu_pages);
+ if (err)
+ panic("failed to setup static percpu area, err=%d\n", err);
+
+ /* link static_chunk in */
+ pcpu_chunk_relocate(static_chunk, -1);
+ pcpu_chunk_addr_insert(static_chunk);
+
+ /* we're done */
+ pcpu_base_addr = (void *)pcpu_chunk_addr(static_chunk, 0, 0);
+ return pcpu_unit_size;
+}
projects / GitHub / exynos8895 / android_kernel_samsung_universal8895.git / commitdiff