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

#ifndef __UBOOT__
#include <log.h>
#include <dm/devres.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#else
#include <linux/compat.h>
#include <malloc.h>
#include <linux/printk.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__
f7ae49fc	2	#include <log.h>
61b29b82	3	#include <dm/devres.h>
c068d44a HS	4	#include <linux/kernel.h>
	5	#include <linux/module.h>
	6	#include <linux/slab.h>
	7	#else
	8	#include <linux/compat.h>
c068d44a	9	#include <malloc.h>
1e94b46f	10	#include <linux/printk.h>
c068d44a HS	11	#endif
	12	#include <linux/list.h>
	13	#include <linux/list_sort.h>
	14
	15	#define MAX_LIST_LENGTH_BITS 20
	16
	17	/*
	18	* Returns a list organized in an intermediate format suited
	19	* to chaining of merge() calls: null-terminated, no reserved or
	20	* sentinel head node, "prev" links not maintained.
	21	*/
	22	static struct list_head merge(void priv,
	23	int (cmp)(void priv, struct list_head *a,
	24	struct list_head *b),
	25	struct list_head a, struct list_head b)
	26	{
	27	struct list_head head, *tail = &head;
	28
	29	while (a && b) {
	30	/* if equal, take 'a' -- important for sort stability */
	31	if ((*cmp)(priv, a, b) <= 0) {
	32	tail->next = a;
	33	a = a->next;
	34	} else {
	35	tail->next = b;
	36	b = b->next;
	37	}
	38	tail = tail->next;
	39	}
	40	tail->next = a?:b;
	41	return head.next;
	42	}
	43
	44	/*
	45	* Combine final list merge with restoration of standard doubly-linked
	46	* list structure. This approach duplicates code from merge(), but
	47	* runs faster than the tidier alternatives of either a separate final
	48	* prev-link restoration pass, or maintaining the prev links
	49	* throughout.
	50	*/
	51	static void merge_and_restore_back_links(void *priv,
	52	int (cmp)(void priv, struct list_head *a,
	53	struct list_head *b),
	54	struct list_head *head,
	55	struct list_head a, struct list_head b)
	56	{
	57	struct list_head *tail = head;
	58
	59	while (a && b) {
	60	/* if equal, take 'a' -- important for sort stability */
	61	if ((*cmp)(priv, a, b) <= 0) {
	62	tail->next = a;
	63	a->prev = tail;
	64	a = a->next;
	65	} else {
	66	tail->next = b;
	67	b->prev = tail;
	68	b = b->next;
	69	}
	70	tail = tail->next;
	71	}
	72	tail->next = a ? : b;
	73
	74	do {
75	/*
76	* In worst cases this loop may run many iterations.
77	* Continue callbacks to the client even though no
78	* element comparison is needed, so the client's cmp()
79	* routine can invoke cond_resched() periodically.
80	*/
81	(*cmp)(priv, tail->next, tail->next);
82
83	tail->next->prev = tail;
84	tail = tail->next;
85	} while (tail->next);
86
87	tail->next = head;
88	head->prev = tail;
89	}
90
91	/**
92	* list_sort - sort a list
93	* @priv: private data, opaque to list_sort(), passed to @cmp
94	* @head: the list to sort
95	* @cmp: the elements comparison function
96	*
97	* This function implements "merge sort", which has O(nlog(n))
98	* complexity.
99	*
100	* The comparison function @cmp must return a negative value if @a
101	* should sort before @b, and a positive value if @a should sort after
102	* @b. If @a and @b are equivalent, and their original relative
103	* ordering is to be preserved, @cmp must return 0.
104	*/
105	void list_sort(void priv, struct list_head head,
106	int (cmp)(void priv, struct list_head *a,
107	struct list_head *b))
108	{
109	struct list_head part[MAX_LIST_LENGTH_BITS+1]; / sorted partial lists
110	-- last slot is a sentinel */
111	int lev; /* index into part[] */
112	int max_lev = 0;
113	struct list_head *list;
114
115	if (list_empty(head))
116	return;
117
118	memset(part, 0, sizeof(part));
119
120	head->prev->next = NULL;
121	list = head->next;
122
123	while (list) {
124	struct list_head *cur = list;
125	list = list->next;
126	cur->next = NULL;
127
128	for (lev = 0; part[lev]; lev++) {
129	cur = merge(priv, cmp, part[lev], cur);
130	part[lev] = NULL;
131	}
132	if (lev > max_lev) {
133	if (unlikely(lev >= ARRAY_SIZE(part)-1)) {
134	printk_once(KERN_DEBUG "list passed to"
135	" list_sort() too long for"
136	" efficiency\n");
137	lev--;
138	}
139	max_lev = lev;
140	}
141	part[lev] = cur;
142	}
143
144	for (lev = 0; lev < max_lev; lev++)
145	if (part[lev])
146	list = merge(priv, cmp, part[lev], list);
147
148	merge_and_restore_back_links(priv, cmp, head, part[max_lev], list);
149	}
150	EXPORT_SYMBOL(list_sort);
151
152	#ifdef CONFIG_TEST_LIST_SORT
153
154	#include <linux/random.h>
155
156	/*
157	* The pattern of set bits in the list length determines which cases
158	* are hit in list_sort().
159	*/
160	#define TEST_LIST_LEN (512+128+2) /* not including head */
161
162	#define TEST_POISON1 0xDEADBEEF
163	#define TEST_POISON2 0xA324354C
164
165	struct debug_el {
166	unsigned int poison1;
167	struct list_head list;
168	unsigned int poison2;
169	int value;
170	unsigned serial;
171	};
172
173	/* Array, containing pointers to all elements in the test list */
174	static struct debug_el **elts __initdata;
175
176	static int __init check(struct debug_el ela, struct debug_el elb)
177	{
178	if (ela->serial >= TEST_LIST_LEN) {
179	printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
180	ela->serial);
181	return -EINVAL;
182	}
183	if (elb->serial >= TEST_LIST_LEN) {
184	printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
185	elb->serial);
186	return -EINVAL;
187	}
188	if (elts[ela->serial] != ela \|\| elts[elb->serial] != elb) {
189	printk(KERN_ERR "list_sort_test: error: phantom element\n");
190	return -EINVAL;
191	}
192	if (ela->poison1 != TEST_POISON1 \|\| ela->poison2 != TEST_POISON2) {
193	printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
194	ela->poison1, ela->poison2);
195	return -EINVAL;
196	}
197	if (elb->poison1 != TEST_POISON1 \|\| elb->poison2 != TEST_POISON2) {
198	printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
199	elb->poison1, elb->poison2);
200	return -EINVAL;
201	}
202	return 0;
203	}
204
205	static int __init cmp(void priv, struct list_head a, struct list_head *b)
206	{
207	struct debug_el ela, elb;
208
209	ela = container_of(a, struct debug_el, list);
210	elb = container_of(b, struct debug_el, list);
211
212	check(ela, elb);
213	return ela->value - elb->value;
214	}
215
216	static int __init list_sort_test(void)
217	{
218	int i, count = 1, err = -EINVAL;
219	struct debug_el *el;
220	struct list_head cur, tmp;
221	LIST_HEAD(head);
222
223	printk(KERN_DEBUG "list_sort_test: start testing list_sort()\n");
224
225	elts = kmalloc(sizeof(void ) TEST_LIST_LEN, GFP_KERNEL);
226	if (!elts) {
227	printk(KERN_ERR "list_sort_test: error: cannot allocate "
228	"memory\n");
229	goto exit;
230	}
231
232	for (i = 0; i < TEST_LIST_LEN; i++) {
233	el = kmalloc(sizeof(*el), GFP_KERNEL);
234	if (!el) {
235	printk(KERN_ERR "list_sort_test: error: cannot "
236	"allocate memory\n");
237	goto exit;
238	}
239	/* force some equivalencies */
240	el->value = prandom_u32() % (TEST_LIST_LEN / 3);
241	el->serial = i;
242	el->poison1 = TEST_POISON1;
243	el->poison2 = TEST_POISON2;
244	elts[i] = el;
245	list_add_tail(&el->list, &head);
246	}
247
248	list_sort(NULL, &head, cmp);
249
250	for (cur = head.next; cur->next != &head; cur = cur->next) {
251	struct debug_el *el1;
252	int cmp_result;
253
254	if (cur->next->prev != cur) {
255	printk(KERN_ERR "list_sort_test: error: list is "
256	"corrupted\n");
257	goto exit;
258	}
259
260	cmp_result = cmp(NULL, cur, cur->next);
261	if (cmp_result > 0) {
262	printk(KERN_ERR "list_sort_test: error: list is not "
263	"sorted\n");
264	goto exit;
265	}
266
267	el = container_of(cur, struct debug_el, list);
268	el1 = container_of(cur->next, struct debug_el, list);
269	if (cmp_result == 0 && el->serial >= el1->serial) {
270	printk(KERN_ERR "list_sort_test: error: order of "
271	"equivalent elements not preserved\n");
272	goto exit;
273	}
274
275	if (check(el, el1)) {
276	printk(KERN_ERR "list_sort_test: error: element check "
277	"failed\n");
278	goto exit;
279	}
280	count++;
281	}
282
283	if (count != TEST_LIST_LEN) {
284	printk(KERN_ERR "list_sort_test: error: bad list length %d",
285	count);
286	goto exit;
287	}
288
289	err = 0;
290	exit:
291	kfree(elts);
292	list_for_each_safe(cur, tmp, &head) {
293	list_del(cur);
294	kfree(container_of(cur, struct debug_el, list));
295	}
296	return err;
297	}
298	module_init(list_sort_test);
299	#endif /* CONFIG_TEST_LIST_SORT */