[J-u-boot.git] / lib / list_sort.c

#ifndef __UBOOT__
#include <dm/devres.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#else
#include <linux/compat.h>
#include <common.h>
#include <malloc.h>
#endif
#include <linux/list.h>
#include <linux/list_sort.h>

#define MAX_LIST_LENGTH_BITS 20

/*
 * Returns a list organized in an intermediate format suited
 * to chaining of merge() calls: null-terminated, no reserved or
 * sentinel head node, "prev" links not maintained.
 */
static struct list_head *merge(void *priv,
				int (*cmp)(void *priv, struct list_head *a,
					struct list_head *b),
				struct list_head *a, struct list_head *b)
{
	struct list_head head, *tail = &head;

	while (a && b) {
		/* if equal, take 'a' -- important for sort stability */
		if ((*cmp)(priv, a, b) <= 0) {
			tail->next = a;
			a = a->next;
		} else {
			tail->next = b;
			b = b->next;
		}
		tail = tail->next;
	}
	tail->next = a?:b;
	return head.next;
}

/*
 * Combine final list merge with restoration of standard doubly-linked
 * list structure.  This approach duplicates code from merge(), but
 * runs faster than the tidier alternatives of either a separate final
 * prev-link restoration pass, or maintaining the prev links
 * throughout.
 */
static void merge_and_restore_back_links(void *priv,
				int (*cmp)(void *priv, struct list_head *a,
					struct list_head *b),
				struct list_head *head,
				struct list_head *a, struct list_head *b)
{
	struct list_head *tail = head;

	while (a && b) {
		/* if equal, take 'a' -- important for sort stability */
		if ((*cmp)(priv, a, b) <= 0) {
			tail->next = a;
			a->prev = tail;
			a = a->next;
		} else {
			tail->next = b;
			b->prev = tail;
			b = b->next;
		}
		tail = tail->next;
	}
	tail->next = a ? : b;

	do {
		/*
		 * In worst cases this loop may run many iterations.
		 * Continue callbacks to the client even though no
		 * element comparison is needed, so the client's cmp()
		 * routine can invoke cond_resched() periodically.
		 */
		(*cmp)(priv, tail->next, tail->next);

		tail->next->prev = tail;
		tail = tail->next;
	} while (tail->next);

	tail->next = head;
	head->prev = tail;
}

/**
 * list_sort - sort a list
 * @priv: private data, opaque to list_sort(), passed to @cmp
 * @head: the list to sort
 * @cmp: the elements comparison function
 *
 * This function implements "merge sort", which has O(nlog(n))
 * complexity.
 *
 * The comparison function @cmp must return a negative value if @a
 * should sort before @b, and a positive value if @a should sort after
 * @b. If @a and @b are equivalent, and their original relative
 * ordering is to be preserved, @cmp must return 0.
 */
void list_sort(void *priv, struct list_head *head,
		int (*cmp)(void *priv, struct list_head *a,
			struct list_head *b))
{
	struct list_head *part[MAX_LIST_LENGTH_BITS+1]; /* sorted partial lists
						-- last slot is a sentinel */
	int lev;  /* index into part[] */
	int max_lev = 0;
	struct list_head *list;

	if (list_empty(head))
		return;

	memset(part, 0, sizeof(part));

	head->prev->next = NULL;
	list = head->next;

	while (list) {
		struct list_head *cur = list;
		list = list->next;
		cur->next = NULL;

		for (lev = 0; part[lev]; lev++) {
			cur = merge(priv, cmp, part[lev], cur);
			part[lev] = NULL;
		}
		if (lev > max_lev) {
			if (unlikely(lev >= ARRAY_SIZE(part)-1)) {
				printk_once(KERN_DEBUG "list passed to"
					" list_sort() too long for"
					" efficiency\n");
				lev--;
			}
			max_lev = lev;
		}
		part[lev] = cur;
	}

	for (lev = 0; lev < max_lev; lev++)
		if (part[lev])
			list = merge(priv, cmp, part[lev], list);

	merge_and_restore_back_links(priv, cmp, head, part[max_lev], list);
}
EXPORT_SYMBOL(list_sort);

#ifdef CONFIG_TEST_LIST_SORT

#include <linux/random.h>

/*
 * The pattern of set bits in the list length determines which cases
 * are hit in list_sort().
 */
#define TEST_LIST_LEN (512+128+2) /* not including head */

#define TEST_POISON1 0xDEADBEEF
#define TEST_POISON2 0xA324354C

struct debug_el {
	unsigned int poison1;
	struct list_head list;
	unsigned int poison2;
	int value;
	unsigned serial;
};

/* Array, containing pointers to all elements in the test list */
static struct debug_el **elts __initdata;

static int __init check(struct debug_el *ela, struct debug_el *elb)
{
	if (ela->serial >= TEST_LIST_LEN) {
		printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
				ela->serial);
		return -EINVAL;
	}
	if (elb->serial >= TEST_LIST_LEN) {
		printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
				elb->serial);
		return -EINVAL;
	}
	if (elts[ela->serial] != ela || elts[elb->serial] != elb) {
		printk(KERN_ERR "list_sort_test: error: phantom element\n");
		return -EINVAL;
	}
	if (ela->poison1 != TEST_POISON1 || ela->poison2 != TEST_POISON2) {
		printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
				ela->poison1, ela->poison2);
		return -EINVAL;
	}
	if (elb->poison1 != TEST_POISON1 || elb->poison2 != TEST_POISON2) {
		printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
				elb->poison1, elb->poison2);
		return -EINVAL;
	}
	return 0;
}

static int __init cmp(void *priv, struct list_head *a, struct list_head *b)
{
	struct debug_el *ela, *elb;

	ela = container_of(a, struct debug_el, list);
	elb = container_of(b, struct debug_el, list);

	check(ela, elb);
	return ela->value - elb->value;
}

static int __init list_sort_test(void)
{
	int i, count = 1, err = -EINVAL;
	struct debug_el *el;
	struct list_head *cur, *tmp;
	LIST_HEAD(head);

	printk(KERN_DEBUG "list_sort_test: start testing list_sort()\n");

	elts = kmalloc(sizeof(void *) * TEST_LIST_LEN, GFP_KERNEL);
	if (!elts) {
		printk(KERN_ERR "list_sort_test: error: cannot allocate "
				"memory\n");
		goto exit;
	}

	for (i = 0; i < TEST_LIST_LEN; i++) {
		el = kmalloc(sizeof(*el), GFP_KERNEL);
		if (!el) {
			printk(KERN_ERR "list_sort_test: error: cannot "
					"allocate memory\n");
			goto exit;
		}
		 /* force some equivalencies */
		el->value = prandom_u32() % (TEST_LIST_LEN / 3);
		el->serial = i;
		el->poison1 = TEST_POISON1;
		el->poison2 = TEST_POISON2;
		elts[i] = el;
		list_add_tail(&el->list, &head);
	}

	list_sort(NULL, &head, cmp);

	for (cur = head.next; cur->next != &head; cur = cur->next) {
		struct debug_el *el1;
		int cmp_result;

		if (cur->next->prev != cur) {
			printk(KERN_ERR "list_sort_test: error: list is "
					"corrupted\n");
			goto exit;
		}

		cmp_result = cmp(NULL, cur, cur->next);
		if (cmp_result > 0) {
			printk(KERN_ERR "list_sort_test: error: list is not "
					"sorted\n");
			goto exit;
		}

		el = container_of(cur, struct debug_el, list);
		el1 = container_of(cur->next, struct debug_el, list);
		if (cmp_result == 0 && el->serial >= el1->serial) {
			printk(KERN_ERR "list_sort_test: error: order of "
					"equivalent elements not preserved\n");
			goto exit;
		}

		if (check(el, el1)) {
			printk(KERN_ERR "list_sort_test: error: element check "
					"failed\n");
			goto exit;
		}
		count++;
	}

	if (count != TEST_LIST_LEN) {
		printk(KERN_ERR "list_sort_test: error: bad list length %d",
				count);
		goto exit;
	}

	err = 0;
exit:
	kfree(elts);
	list_for_each_safe(cur, tmp, &head) {
		list_del(cur);
		kfree(container_of(cur, struct debug_el, list));
	}
	return err;
}
module_init(list_sort_test);
#endif /* CONFIG_TEST_LIST_SORT */
Commit	Line	Data
c068d44a	1	#ifndef __UBOOT__
61b29b82	2	#include <dm/devres.h>
c068d44a HS	3	#include <linux/kernel.h>
	4	#include <linux/module.h>
	5	#include <linux/slab.h>
	6	#else
	7	#include <linux/compat.h>
	8	#include <common.h>
	9	#include <malloc.h>
	10	#endif
	11	#include <linux/list.h>
	12	#include <linux/list_sort.h>
	13
	14	#define MAX_LIST_LENGTH_BITS 20
	15
	16	/*
	17	* Returns a list organized in an intermediate format suited
	18	* to chaining of merge() calls: null-terminated, no reserved or
	19	* sentinel head node, "prev" links not maintained.
	20	*/
	21	static struct list_head merge(void priv,
	22	int (cmp)(void priv, struct list_head *a,
	23	struct list_head *b),
	24	struct list_head a, struct list_head b)
	25	{
	26	struct list_head head, *tail = &head;
	27
	28	while (a && b) {
	29	/* if equal, take 'a' -- important for sort stability */
	30	if ((*cmp)(priv, a, b) <= 0) {
	31	tail->next = a;
	32	a = a->next;
	33	} else {
	34	tail->next = b;
	35	b = b->next;
	36	}
	37	tail = tail->next;
	38	}
	39	tail->next = a?:b;
	40	return head.next;
	41	}
	42
	43	/*
	44	* Combine final list merge with restoration of standard doubly-linked
	45	* list structure. This approach duplicates code from merge(), but
	46	* runs faster than the tidier alternatives of either a separate final
	47	* prev-link restoration pass, or maintaining the prev links
	48	* throughout.
	49	*/
	50	static void merge_and_restore_back_links(void *priv,
	51	int (cmp)(void priv, struct list_head *a,
	52	struct list_head *b),
	53	struct list_head *head,
	54	struct list_head a, struct list_head b)
	55	{
	56	struct list_head *tail = head;
	57
	58	while (a && b) {
	59	/* if equal, take 'a' -- important for sort stability */
	60	if ((*cmp)(priv, a, b) <= 0) {
	61	tail->next = a;
	62	a->prev = tail;
	63	a = a->next;
	64	} else {
	65	tail->next = b;
	66	b->prev = tail;
67	b = b->next;
68	}
69	tail = tail->next;
70	}
71	tail->next = a ? : b;
72
73	do {
74	/*
75	* In worst cases this loop may run many iterations.
76	* Continue callbacks to the client even though no
77	* element comparison is needed, so the client's cmp()
78	* routine can invoke cond_resched() periodically.
79	*/
80	(*cmp)(priv, tail->next, tail->next);
81
82	tail->next->prev = tail;
83	tail = tail->next;
84	} while (tail->next);
85
86	tail->next = head;
87	head->prev = tail;
88	}
89
90	/**
91	* list_sort - sort a list
92	* @priv: private data, opaque to list_sort(), passed to @cmp
93	* @head: the list to sort
94	* @cmp: the elements comparison function
95	*
96	* This function implements "merge sort", which has O(nlog(n))
97	* complexity.
98	*
99	* The comparison function @cmp must return a negative value if @a
100	* should sort before @b, and a positive value if @a should sort after
101	* @b. If @a and @b are equivalent, and their original relative
102	* ordering is to be preserved, @cmp must return 0.
103	*/
104	void list_sort(void priv, struct list_head head,
105	int (cmp)(void priv, struct list_head *a,
106	struct list_head *b))
107	{
108	struct list_head part[MAX_LIST_LENGTH_BITS+1]; / sorted partial lists
109	-- last slot is a sentinel */
110	int lev; /* index into part[] */
111	int max_lev = 0;
112	struct list_head *list;
113
114	if (list_empty(head))
115	return;
116
117	memset(part, 0, sizeof(part));
118
119	head->prev->next = NULL;
120	list = head->next;
121
122	while (list) {
123	struct list_head *cur = list;
124	list = list->next;
125	cur->next = NULL;
126
127	for (lev = 0; part[lev]; lev++) {
128	cur = merge(priv, cmp, part[lev], cur);
129	part[lev] = NULL;
130	}
131	if (lev > max_lev) {
132	if (unlikely(lev >= ARRAY_SIZE(part)-1)) {
133	printk_once(KERN_DEBUG "list passed to"
134	" list_sort() too long for"
135	" efficiency\n");
136	lev--;
137	}
138	max_lev = lev;
139	}
140	part[lev] = cur;
141	}
142
143	for (lev = 0; lev < max_lev; lev++)
144	if (part[lev])
145	list = merge(priv, cmp, part[lev], list);
146
147	merge_and_restore_back_links(priv, cmp, head, part[max_lev], list);
148	}
149	EXPORT_SYMBOL(list_sort);
150
151	#ifdef CONFIG_TEST_LIST_SORT
152
153	#include <linux/random.h>
154
155	/*
156	* The pattern of set bits in the list length determines which cases
157	* are hit in list_sort().
158	*/
159	#define TEST_LIST_LEN (512+128+2) /* not including head */
160
161	#define TEST_POISON1 0xDEADBEEF
162	#define TEST_POISON2 0xA324354C
163
164	struct debug_el {
165	unsigned int poison1;
166	struct list_head list;
167	unsigned int poison2;
168	int value;
169	unsigned serial;
170	};
171
172	/* Array, containing pointers to all elements in the test list */
173	static struct debug_el **elts __initdata;
174
175	static int __init check(struct debug_el ela, struct debug_el elb)
176	{
177	if (ela->serial >= TEST_LIST_LEN) {
178	printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
179	ela->serial);
180	return -EINVAL;
181	}
182	if (elb->serial >= TEST_LIST_LEN) {
183	printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
184	elb->serial);
185	return -EINVAL;
186	}
187	if (elts[ela->serial] != ela \|\| elts[elb->serial] != elb) {
188	printk(KERN_ERR "list_sort_test: error: phantom element\n");
189	return -EINVAL;
190	}
191	if (ela->poison1 != TEST_POISON1 \|\| ela->poison2 != TEST_POISON2) {
192	printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
193	ela->poison1, ela->poison2);
194	return -EINVAL;
195	}
196	if (elb->poison1 != TEST_POISON1 \|\| elb->poison2 != TEST_POISON2) {
197	printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
198	elb->poison1, elb->poison2);
199	return -EINVAL;
200	}
201	return 0;
202	}
203
204	static int __init cmp(void priv, struct list_head a, struct list_head *b)
205	{
206	struct debug_el ela, elb;
207
208	ela = container_of(a, struct debug_el, list);
209	elb = container_of(b, struct debug_el, list);
210
211	check(ela, elb);
212	return ela->value - elb->value;
213	}
214
215	static int __init list_sort_test(void)
216	{
217	int i, count = 1, err = -EINVAL;
218	struct debug_el *el;
219	struct list_head cur, tmp;
220	LIST_HEAD(head);
221
222	printk(KERN_DEBUG "list_sort_test: start testing list_sort()\n");
223
224	elts = kmalloc(sizeof(void ) TEST_LIST_LEN, GFP_KERNEL);
225	if (!elts) {
226	printk(KERN_ERR "list_sort_test: error: cannot allocate "
227	"memory\n");
228	goto exit;
229	}
230
231	for (i = 0; i < TEST_LIST_LEN; i++) {
232	el = kmalloc(sizeof(*el), GFP_KERNEL);
233	if (!el) {
234	printk(KERN_ERR "list_sort_test: error: cannot "
235	"allocate memory\n");
236	goto exit;
237	}
238	/* force some equivalencies */
239	el->value = prandom_u32() % (TEST_LIST_LEN / 3);
240	el->serial = i;
241	el->poison1 = TEST_POISON1;
242	el->poison2 = TEST_POISON2;
243	elts[i] = el;
244	list_add_tail(&el->list, &head);
245	}
246
247	list_sort(NULL, &head, cmp);
248
249	for (cur = head.next; cur->next != &head; cur = cur->next) {
250	struct debug_el *el1;
251	int cmp_result;
252
253	if (cur->next->prev != cur) {
254	printk(KERN_ERR "list_sort_test: error: list is "
255	"corrupted\n");
256	goto exit;
257	}
258
259	cmp_result = cmp(NULL, cur, cur->next);
260	if (cmp_result > 0) {
261	printk(KERN_ERR "list_sort_test: error: list is not "
262	"sorted\n");
263	goto exit;
264	}
265
266	el = container_of(cur, struct debug_el, list);
267	el1 = container_of(cur->next, struct debug_el, list);
268	if (cmp_result == 0 && el->serial >= el1->serial) {
269	printk(KERN_ERR "list_sort_test: error: order of "
270	"equivalent elements not preserved\n");
271	goto exit;
272	}
273
274	if (check(el, el1)) {
275	printk(KERN_ERR "list_sort_test: error: element check "
276	"failed\n");
277	goto exit;
278	}
279	count++;
280	}
281
282	if (count != TEST_LIST_LEN) {
283	printk(KERN_ERR "list_sort_test: error: bad list length %d",
284	count);
285	goto exit;
286	}
287
288	err = 0;
289	exit:
290	kfree(elts);
291	list_for_each_safe(cur, tmp, &head) {
292	list_del(cur);
293	kfree(container_of(cur, struct debug_el, list));
294	}
295	return err;
296	}
297	module_init(list_sort_test);
298	#endif /* CONFIG_TEST_LIST_SORT */