1/*
  2 * CMA DebugFS Interface
  3 *
  4 * Copyright (c) 2015 Sasha Levin <sasha.levin@oracle.com>
  5 */
  6
  7
  8#include <linux/debugfs.h>
  9#include <linux/cma.h>
 10#include <linux/list.h>
 11#include <linux/kernel.h>
 12#include <linux/slab.h>
 13#include <linux/mm_types.h>
 14
 15#include "cma.h"
 16
 17struct cma_mem {
 18	struct hlist_node node;
 19	struct page *p;
 20	unsigned long n;
 21};
 22
 23static struct dentry *cma_debugfs_root;
 24
 25static int cma_debugfs_get(void *data, u64 *val)
 26{
 27	unsigned long *p = data;
 28
 29	*val = *p;
 30
 31	return 0;
 32}
 33DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
 34
 35static int cma_used_get(void *data, u64 *val)
 36{
 37	struct cma *cma = data;
 38	unsigned long used;
 39
 40	mutex_lock(&cma->lock);
 41	/* pages counter is smaller than sizeof(int) */
 42	used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma));
 43	mutex_unlock(&cma->lock);
 44	*val = (u64)used << cma->order_per_bit;
 45
 46	return 0;
 47}
 48DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
 49
 50static int cma_maxchunk_get(void *data, u64 *val)
 51{
 52	struct cma *cma = data;
 53	unsigned long maxchunk = 0;
 54	unsigned long start, end = 0;
 55	unsigned long bitmap_maxno = cma_bitmap_maxno(cma);
 56
 57	mutex_lock(&cma->lock);
 58	for (;;) {
 59		start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end);
 60		if (start >= cma->count)
 61			break;
 62		end = find_next_bit(cma->bitmap, bitmap_maxno, start);
 63		maxchunk = max(end - start, maxchunk);
 64	}
 65	mutex_unlock(&cma->lock);
 66	*val = (u64)maxchunk << cma->order_per_bit;
 67
 68	return 0;
 69}
 70DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
 71
 72static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
 73{
 74	spin_lock(&cma->mem_head_lock);
 75	hlist_add_head(&mem->node, &cma->mem_head);
 76	spin_unlock(&cma->mem_head_lock);
 77}
 78
 79static struct cma_mem *cma_get_entry_from_list(struct cma *cma)
 80{
 81	struct cma_mem *mem = NULL;
 82
 83	spin_lock(&cma->mem_head_lock);
 84	if (!hlist_empty(&cma->mem_head)) {
 85		mem = hlist_entry(cma->mem_head.first, struct cma_mem, node);
 86		hlist_del_init(&mem->node);
 87	}
 88	spin_unlock(&cma->mem_head_lock);
 89
 90	return mem;
 91}
 92
 93static int cma_free_mem(struct cma *cma, int count)
 94{
 95	struct cma_mem *mem = NULL;
 96
 97	while (count) {
 98		mem = cma_get_entry_from_list(cma);
 99		if (mem == NULL)
100			return 0;
101
102		if (mem->n <= count) {
103			cma_release(cma, mem->p, mem->n);
104			count -= mem->n;
105			kfree(mem);
106		} else if (cma->order_per_bit == 0) {
107			cma_release(cma, mem->p, count);
108			mem->p += count;
109			mem->n -= count;
110			count = 0;
111			cma_add_to_cma_mem_list(cma, mem);
112		} else {
113			pr_debug("cma: cannot release partial block when order_per_bit != 0\n");
114			cma_add_to_cma_mem_list(cma, mem);
115			break;
116		}
117	}
118
119	return 0;
120
121}
122
123static int cma_free_write(void *data, u64 val)
124{
125	int pages = val;
126	struct cma *cma = data;
127
128	return cma_free_mem(cma, pages);
129}
130DEFINE_SIMPLE_ATTRIBUTE(cma_free_fops, NULL, cma_free_write, "%llu\n");
131
132static int cma_alloc_mem(struct cma *cma, int count)
133{
134	struct cma_mem *mem;
135	struct page *p;
136
137	mem = kzalloc(sizeof(*mem), GFP_KERNEL);
138	if (!mem)
139		return -ENOMEM;
140
141	p = cma_alloc(cma, count, 0);
142	if (!p) {
143		kfree(mem);
144		return -ENOMEM;
145	}
146
147	mem->p = p;
148	mem->n = count;
149
150	cma_add_to_cma_mem_list(cma, mem);
151
152	return 0;
153}
154
155static int cma_alloc_write(void *data, u64 val)
156{
157	int pages = val;
158	struct cma *cma = data;
159
160	return cma_alloc_mem(cma, pages);
161}
162DEFINE_SIMPLE_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n");
163
164static void cma_debugfs_add_one(struct cma *cma, int idx)
165{
166	struct dentry *tmp;
167	char name[16];
168	int u32s;
169
170	sprintf(name, "cma-%d", idx);
171
172	tmp = debugfs_create_dir(name, cma_debugfs_root);
173
174	debugfs_create_file("alloc", S_IWUSR, tmp, cma,
175				&cma_alloc_fops);
176
177	debugfs_create_file("free", S_IWUSR, tmp, cma,
178				&cma_free_fops);
179
180	debugfs_create_file("base_pfn", S_IRUGO, tmp,
181				&cma->base_pfn, &cma_debugfs_fops);
182	debugfs_create_file("count", S_IRUGO, tmp,
183				&cma->count, &cma_debugfs_fops);
184	debugfs_create_file("order_per_bit", S_IRUGO, tmp,
185				&cma->order_per_bit, &cma_debugfs_fops);
186	debugfs_create_file("used", S_IRUGO, tmp, cma, &cma_used_fops);
187	debugfs_create_file("maxchunk", S_IRUGO, tmp, cma, &cma_maxchunk_fops);
188
189	u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
190	debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s);
191}
192
193static int __init cma_debugfs_init(void)
194{
195	int i;
196
197	cma_debugfs_root = debugfs_create_dir("cma", NULL);
198	if (!cma_debugfs_root)
199		return -ENOMEM;
200
201	for (i = 0; i < cma_area_count; i++)
202		cma_debugfs_add_one(&cma_areas[i], i);
203
204	return 0;
205}
206late_initcall(cma_debugfs_init);