Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 1 | |
| 2 | #define pr_fmt(fmt) "list_sort_test: " fmt |
| 3 | |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 4 | #include <linux/kernel.h> |
Rasmus Villemoes | 7259fa0 | 2015-02-12 15:02:48 -0800 | [diff] [blame] | 5 | #include <linux/bug.h> |
| 6 | #include <linux/compiler.h> |
| 7 | #include <linux/export.h> |
| 8 | #include <linux/string.h> |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 9 | #include <linux/list_sort.h> |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 10 | #include <linux/list.h> |
| 11 | |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 12 | #define MAX_LIST_LENGTH_BITS 20 |
| 13 | |
| 14 | /* |
| 15 | * Returns a list organized in an intermediate format suited |
| 16 | * to chaining of merge() calls: null-terminated, no reserved or |
| 17 | * sentinel head node, "prev" links not maintained. |
| 18 | */ |
| 19 | static struct list_head *merge(void *priv, |
| 20 | int (*cmp)(void *priv, struct list_head *a, |
| 21 | struct list_head *b), |
| 22 | struct list_head *a, struct list_head *b) |
| 23 | { |
| 24 | struct list_head head, *tail = &head; |
| 25 | |
| 26 | while (a && b) { |
| 27 | /* if equal, take 'a' -- important for sort stability */ |
| 28 | if ((*cmp)(priv, a, b) <= 0) { |
| 29 | tail->next = a; |
| 30 | a = a->next; |
| 31 | } else { |
| 32 | tail->next = b; |
| 33 | b = b->next; |
| 34 | } |
| 35 | tail = tail->next; |
| 36 | } |
| 37 | tail->next = a?:b; |
| 38 | return head.next; |
| 39 | } |
| 40 | |
| 41 | /* |
| 42 | * Combine final list merge with restoration of standard doubly-linked |
| 43 | * list structure. This approach duplicates code from merge(), but |
| 44 | * runs faster than the tidier alternatives of either a separate final |
| 45 | * prev-link restoration pass, or maintaining the prev links |
| 46 | * throughout. |
| 47 | */ |
| 48 | static void merge_and_restore_back_links(void *priv, |
| 49 | int (*cmp)(void *priv, struct list_head *a, |
| 50 | struct list_head *b), |
| 51 | struct list_head *head, |
| 52 | struct list_head *a, struct list_head *b) |
| 53 | { |
| 54 | struct list_head *tail = head; |
Rasmus Villemoes | 61b3d6c | 2014-08-06 16:09:44 -0700 | [diff] [blame] | 55 | u8 count = 0; |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 56 | |
| 57 | while (a && b) { |
| 58 | /* if equal, take 'a' -- important for sort stability */ |
| 59 | if ((*cmp)(priv, a, b) <= 0) { |
| 60 | tail->next = a; |
| 61 | a->prev = tail; |
| 62 | a = a->next; |
| 63 | } else { |
| 64 | tail->next = b; |
| 65 | b->prev = tail; |
| 66 | b = b->next; |
| 67 | } |
| 68 | tail = tail->next; |
| 69 | } |
| 70 | tail->next = a ? : b; |
| 71 | |
| 72 | do { |
| 73 | /* |
| 74 | * In worst cases this loop may run many iterations. |
| 75 | * Continue callbacks to the client even though no |
| 76 | * element comparison is needed, so the client's cmp() |
| 77 | * routine can invoke cond_resched() periodically. |
| 78 | */ |
Rasmus Villemoes | 61b3d6c | 2014-08-06 16:09:44 -0700 | [diff] [blame] | 79 | if (unlikely(!(++count))) |
| 80 | (*cmp)(priv, tail->next, tail->next); |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 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 | |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 90 | /** |
Don Mullis | 02b12b7 | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 91 | * list_sort - sort a list |
| 92 | * @priv: private data, opaque to list_sort(), passed to @cmp |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 93 | * @head: the list to sort |
| 94 | * @cmp: the elements comparison function |
| 95 | * |
Don Mullis | 02b12b7 | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 96 | * This function implements "merge sort", which has O(nlog(n)) |
| 97 | * complexity. |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 98 | * |
Don Mullis | 02b12b7 | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 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. |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 103 | */ |
| 104 | void list_sort(void *priv, struct list_head *head, |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 105 | int (*cmp)(void *priv, struct list_head *a, |
| 106 | struct list_head *b)) |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 107 | { |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 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; |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 113 | |
| 114 | if (list_empty(head)) |
| 115 | return; |
| 116 | |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 117 | memset(part, 0, sizeof(part)); |
| 118 | |
| 119 | head->prev->next = NULL; |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 120 | list = head->next; |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 121 | |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 122 | while (list) { |
| 123 | struct list_head *cur = list; |
| 124 | list = list->next; |
| 125 | cur->next = NULL; |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 126 | |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 127 | for (lev = 0; part[lev]; lev++) { |
| 128 | cur = merge(priv, cmp, part[lev], cur); |
| 129 | part[lev] = NULL; |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 130 | } |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 131 | if (lev > max_lev) { |
| 132 | if (unlikely(lev >= ARRAY_SIZE(part)-1)) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 133 | printk_once(KERN_DEBUG "list too long for efficiency\n"); |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 134 | lev--; |
| 135 | } |
| 136 | max_lev = lev; |
| 137 | } |
| 138 | part[lev] = cur; |
Dave Chinner | 2c76127 | 2010-01-12 17:39:16 +1100 | [diff] [blame] | 139 | } |
| 140 | |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 141 | for (lev = 0; lev < max_lev; lev++) |
| 142 | if (part[lev]) |
| 143 | list = merge(priv, cmp, part[lev], list); |
| 144 | |
| 145 | merge_and_restore_back_links(priv, cmp, head, part[max_lev], list); |
| 146 | } |
| 147 | EXPORT_SYMBOL(list_sort); |
| 148 | |
Artem Bityutskiy | 6d411e6 | 2010-10-26 14:23:05 -0700 | [diff] [blame] | 149 | #ifdef CONFIG_TEST_LIST_SORT |
Artem Bityutskiy | eeee9eb | 2010-10-26 14:23:06 -0700 | [diff] [blame] | 150 | |
Rasmus Villemoes | 7259fa0 | 2015-02-12 15:02:48 -0800 | [diff] [blame] | 151 | #include <linux/slab.h> |
Artem Bityutskiy | eeee9eb | 2010-10-26 14:23:06 -0700 | [diff] [blame] | 152 | #include <linux/random.h> |
| 153 | |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 154 | /* |
| 155 | * The pattern of set bits in the list length determines which cases |
| 156 | * are hit in list_sort(). |
| 157 | */ |
Artem Bityutskiy | eeee9eb | 2010-10-26 14:23:06 -0700 | [diff] [blame] | 158 | #define TEST_LIST_LEN (512+128+2) /* not including head */ |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 159 | |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 160 | #define TEST_POISON1 0xDEADBEEF |
| 161 | #define TEST_POISON2 0xA324354C |
| 162 | |
| 163 | struct debug_el { |
| 164 | unsigned int poison1; |
| 165 | struct list_head list; |
| 166 | unsigned int poison2; |
| 167 | int value; |
| 168 | unsigned serial; |
| 169 | }; |
| 170 | |
| 171 | /* Array, containing pointers to all elements in the test list */ |
| 172 | static struct debug_el **elts __initdata; |
| 173 | |
| 174 | static int __init check(struct debug_el *ela, struct debug_el *elb) |
| 175 | { |
| 176 | if (ela->serial >= TEST_LIST_LEN) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 177 | pr_err("error: incorrect serial %d\n", ela->serial); |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 178 | return -EINVAL; |
| 179 | } |
| 180 | if (elb->serial >= TEST_LIST_LEN) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 181 | pr_err("error: incorrect serial %d\n", elb->serial); |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 182 | return -EINVAL; |
| 183 | } |
| 184 | if (elts[ela->serial] != ela || elts[elb->serial] != elb) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 185 | pr_err("error: phantom element\n"); |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 186 | return -EINVAL; |
| 187 | } |
| 188 | if (ela->poison1 != TEST_POISON1 || ela->poison2 != TEST_POISON2) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 189 | pr_err("error: bad poison: %#x/%#x\n", |
| 190 | ela->poison1, ela->poison2); |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 191 | return -EINVAL; |
| 192 | } |
| 193 | if (elb->poison1 != TEST_POISON1 || elb->poison2 != TEST_POISON2) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 194 | pr_err("error: bad poison: %#x/%#x\n", |
| 195 | elb->poison1, elb->poison2); |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 196 | return -EINVAL; |
| 197 | } |
| 198 | return 0; |
| 199 | } |
| 200 | |
| 201 | static int __init cmp(void *priv, struct list_head *a, struct list_head *b) |
| 202 | { |
| 203 | struct debug_el *ela, *elb; |
| 204 | |
| 205 | ela = container_of(a, struct debug_el, list); |
| 206 | elb = container_of(b, struct debug_el, list); |
| 207 | |
| 208 | check(ela, elb); |
| 209 | return ela->value - elb->value; |
| 210 | } |
| 211 | |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 212 | static int __init list_sort_test(void) |
| 213 | { |
Rasmus Villemoes | 27d555d | 2014-08-06 16:09:38 -0700 | [diff] [blame] | 214 | int i, count = 1, err = -ENOMEM; |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 215 | struct debug_el *el; |
Rasmus Villemoes | 6941230 | 2014-08-06 16:09:42 -0700 | [diff] [blame] | 216 | struct list_head *cur; |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 217 | LIST_HEAD(head); |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 218 | |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 219 | pr_debug("start testing list_sort()\n"); |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 220 | |
Rasmus Villemoes | 6941230 | 2014-08-06 16:09:42 -0700 | [diff] [blame] | 221 | elts = kcalloc(TEST_LIST_LEN, sizeof(*elts), GFP_KERNEL); |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 222 | if (!elts) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 223 | pr_err("error: cannot allocate memory\n"); |
Rasmus Villemoes | 6941230 | 2014-08-06 16:09:42 -0700 | [diff] [blame] | 224 | return err; |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 225 | } |
| 226 | |
Artem Bityutskiy | eeee9eb | 2010-10-26 14:23:06 -0700 | [diff] [blame] | 227 | for (i = 0; i < TEST_LIST_LEN; i++) { |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 228 | el = kmalloc(sizeof(*el), GFP_KERNEL); |
| 229 | if (!el) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 230 | pr_err("error: cannot allocate memory\n"); |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 231 | goto exit; |
| 232 | } |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 233 | /* force some equivalencies */ |
Akinobu Mita | f39fee5 | 2013-04-29 16:21:28 -0700 | [diff] [blame] | 234 | el->value = prandom_u32() % (TEST_LIST_LEN / 3); |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 235 | el->serial = i; |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 236 | el->poison1 = TEST_POISON1; |
| 237 | el->poison2 = TEST_POISON2; |
| 238 | elts[i] = el; |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 239 | list_add_tail(&el->list, &head); |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 240 | } |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 241 | |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 242 | list_sort(NULL, &head, cmp); |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 243 | |
Rasmus Villemoes | 27d555d | 2014-08-06 16:09:38 -0700 | [diff] [blame] | 244 | err = -EINVAL; |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 245 | for (cur = head.next; cur->next != &head; cur = cur->next) { |
| 246 | struct debug_el *el1; |
| 247 | int cmp_result; |
| 248 | |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 249 | if (cur->next->prev != cur) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 250 | pr_err("error: list is corrupted\n"); |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 251 | goto exit; |
| 252 | } |
| 253 | |
| 254 | cmp_result = cmp(NULL, cur, cur->next); |
| 255 | if (cmp_result > 0) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 256 | pr_err("error: list is not sorted\n"); |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 257 | goto exit; |
| 258 | } |
| 259 | |
| 260 | el = container_of(cur, struct debug_el, list); |
| 261 | el1 = container_of(cur->next, struct debug_el, list); |
| 262 | if (cmp_result == 0 && el->serial >= el1->serial) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 263 | pr_err("error: order of equivalent elements not " |
| 264 | "preserved\n"); |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 265 | goto exit; |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 266 | } |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 267 | |
| 268 | if (check(el, el1)) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 269 | pr_err("error: element check failed\n"); |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 270 | goto exit; |
| 271 | } |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 272 | count++; |
| 273 | } |
Rasmus Villemoes | 9d418dc | 2014-08-06 16:09:40 -0700 | [diff] [blame] | 274 | if (head.prev != cur) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 275 | pr_err("error: list is corrupted\n"); |
Rasmus Villemoes | 9d418dc | 2014-08-06 16:09:40 -0700 | [diff] [blame] | 276 | goto exit; |
| 277 | } |
| 278 | |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 279 | |
Artem Bityutskiy | eeee9eb | 2010-10-26 14:23:06 -0700 | [diff] [blame] | 280 | if (count != TEST_LIST_LEN) { |
Andrew Morton | d0da23b | 2014-08-06 16:09:46 -0700 | [diff] [blame] | 281 | pr_err("error: bad list length %d", count); |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 282 | goto exit; |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 283 | } |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 284 | |
| 285 | err = 0; |
| 286 | exit: |
Rasmus Villemoes | 6941230 | 2014-08-06 16:09:42 -0700 | [diff] [blame] | 287 | for (i = 0; i < TEST_LIST_LEN; i++) |
| 288 | kfree(elts[i]); |
Artem Bityutskiy | 041b78f | 2010-10-26 14:23:08 -0700 | [diff] [blame] | 289 | kfree(elts); |
Artem Bityutskiy | f3dc0e3 | 2010-10-26 14:23:07 -0700 | [diff] [blame] | 290 | return err; |
Don Mullis | 835cc0c | 2010-03-05 13:43:15 -0800 | [diff] [blame] | 291 | } |
Paul Gortmaker | 4c7217f | 2015-05-01 21:57:34 -0400 | [diff] [blame] | 292 | late_initcall(list_sort_test); |
Artem Bityutskiy | 6d411e6 | 2010-10-26 14:23:05 -0700 | [diff] [blame] | 293 | #endif /* CONFIG_TEST_LIST_SORT */ |