from linux 3.14:
commit 455c6fdbd219161bd09b1165f11699d6d73de11c Author: Linus Torvalds torvalds@linux-foundation.org Date: Sun Mar 30 20:40:15 2014 -0700
Linux 3.14
Needed for the MTD/UBI/UBIFS resync
Signed-off-by: Heiko Schocher hs@denx.de Cc: Marek Vasut marex@denx.de Cc: Sergey Lapin slapin@ossfans.org Cc: Scott Wood scottwood@freescale.com --- include/linux/list_sort.h | 11 ++ lib/Makefile | 1 + lib/list_sort.c | 298 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 310 insertions(+) create mode 100644 include/linux/list_sort.h create mode 100644 lib/list_sort.c
diff --git a/include/linux/list_sort.h b/include/linux/list_sort.h new file mode 100644 index 0000000..1a2df2e --- /dev/null +++ b/include/linux/list_sort.h @@ -0,0 +1,11 @@ +#ifndef _LINUX_LIST_SORT_H +#define _LINUX_LIST_SORT_H + +#include <linux/types.h> + +struct list_head; + +void list_sort(void *priv, struct list_head *head, + int (*cmp)(void *priv, struct list_head *a, + struct list_head *b)); +#endif diff --git a/lib/Makefile b/lib/Makefile index 27e4f78..71b7fb8 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -40,6 +40,7 @@ obj-y += strmhz.o obj-$(CONFIG_TPM) += tpm.o obj-$(CONFIG_RBTREE) += rbtree.o obj-$(CONFIG_BITREVERSE) += bitrev.o +obj-y += list_sort.o endif
ifdef CONFIG_SPL_BUILD diff --git a/lib/list_sort.c b/lib/list_sort.c new file mode 100644 index 0000000..81de0a1 --- /dev/null +++ b/lib/list_sort.c @@ -0,0 +1,298 @@ +#define __UBOOT__ +#ifndef __UBOOT__ +#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 */