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// SPDX-License-Identifier: GPL-2.0
/*
* CMA DebugFS Interface
*
* Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com>
*/
#include <linux/debugfs.h>
#include <linux/cma.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm_types.h>
#include "cma.h"
struct cma_mem {
struct hlist_node node;
struct page *p;
unsigned long n;
};
static struct dentry *cma_debugfs_root;
static int cma_debugfs_get(void *data, u64 *val)
{
unsigned long *p = data;
*val = *p;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
static int cma_used_get(void *data, u64 *val)
{
struct cma *cma = data;
unsigned long used;
mutex_lock(&cma->lock);
/* pages counter is smaller than sizeof(int) */
used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma));
mutex_unlock(&cma->lock);
*val = (u64)used << cma->order_per_bit;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
static int cma_maxchunk_get(void *data, u64 *val)
{
struct cma *cma = data;
unsigned long maxchunk = 0;
unsigned long start, end = 0;
unsigned long bitmap_maxno = cma_bitmap_maxno(cma);
mutex_lock(&cma->lock);
for (;;) {
start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end);
if (start >= bitmap_maxno)
break;
end = find_next_bit(cma->bitmap, bitmap_maxno, start);
maxchunk = max(end - start, maxchunk);
}
mutex_unlock(&cma->lock);
*val = (u64)maxchunk << cma->order_per_bit;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
{
spin_lock(&cma->mem_head_lock);
hlist_add_head(&mem->node, &cma->mem_head);
spin_unlock(&cma->mem_head_lock);
}
static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
{
struct cma_mem *mem = NULL;
spin_lock(&cma->mem_head_lock);
if (!hlist_empty(&cma->mem_head)) {
mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
hlist_del_init(&mem->node);
}
spin_unlock(&cma->mem_head_lock);
return mem;
}
static int cma_free_mem(struct cma *cma, int count)
{
struct cma_mem *mem = NULL;
while (count) {
mem = cma_get_entry_from_list(cma);
if (mem == NULL)
return 0;
if (mem->n <= count) {
cma_release(cma, mem->p, mem->n);
count -= mem->n;
kfree(mem);
} else if (cma->order_per_bit == 0) {
cma_release(cma, mem->p, count);
mem->p += count;
mem->n -= count;
count = 0;
cma_add_to_cma_mem_list(cma, mem);
} else {
pr_debug("cma: cannot release partial block when order_per_bit != 0\n");
cma_add_to_cma_mem_list(cma, mem);
break;
}
}
return 0;
}
static int cma_free_write(void *data, u64 val)
{
int pages = val;
struct cma *cma = data;
return cma_free_mem(cma, pages);
}
DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
static int cma_alloc_mem(struct cma *cma, int count)
{
struct cma_mem *mem;
struct page *p;
mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
p = cma_alloc(cma, count, 0, false);
if (!p) {
kfree(mem);
return -ENOMEM;
}
mem->p = p;
mem->n = count;
cma_add_to_cma_mem_list(cma, mem);
return 0;
}
static int cma_alloc_write(void *data, u64 val)
{
int pages = val;
struct cma *cma = data;
return cma_alloc_mem(cma, pages);
}
DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
static void cma_debugfs_add_one(struct cma *cma, int idx)
{
struct dentry *tmp;
char name[16];
int u32s;
scnprintf(name, sizeof(name), "cma-%s", cma->name);
tmp = debugfs_create_dir(name, cma_debugfs_root);
debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops);
debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops);
debugfs_create_file("base_pfn", 0444, tmp,
&cma->base_pfn, &cma_debugfs_fops);
debugfs_create_file("count", 0444, tmp, &cma->count, &cma_debugfs_fops);
debugfs_create_file("order_per_bit", 0444, tmp,
&cma->order_per_bit, &cma_debugfs_fops);
debugfs_create_file("used", 0444, tmp, cma, &cma_used_fops);
debugfs_create_file("maxchunk", 0444, tmp, cma, &cma_maxchunk_fops);
u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
debugfs_create_u32_array("bitmap", 0444, tmp, (u32 *)cma->bitmap, u32s);
}
static int __init cma_debugfs_init(void)
{
int i;
cma_debugfs_root = debugfs_create_dir("cma", NULL);
if (!cma_debugfs_root)
return -ENOMEM;
for (i = 0; i < cma_area_count; i++)
cma_debugfs_add_one(&cma_areas[i], i);
return 0;
}
late_initcall(cma_debugfs_init);
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