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-rw-r--r--fs/ubifs/gc.c96
1 files changed, 1 insertions, 95 deletions
diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
index 618c2701d3a7..e5a3d8e96bb7 100644
--- a/fs/ubifs/gc.c
+++ b/fs/ubifs/gc.c
@@ -54,6 +54,7 @@
54 */ 54 */
55 55
56#include <linux/pagemap.h> 56#include <linux/pagemap.h>
57#include <linux/list_sort.h>
57#include "ubifs.h" 58#include "ubifs.h"
58 59
59/* 60/*
@@ -108,101 +109,6 @@ static int switch_gc_head(struct ubifs_info *c)
108} 109}
109 110
110/** 111/**
111 * list_sort - sort a list.
112 * @priv: private data, passed to @cmp
113 * @head: the list to sort
114 * @cmp: the elements comparison function
115 *
116 * This function has been implemented by Mark J Roberts <mjr@znex.org>. It
117 * implements "merge sort" which has O(nlog(n)) complexity. The list is sorted
118 * in ascending order.
119 *
120 * The comparison function @cmp is supposed to return a negative value if @a is
121 * than @b, and a positive value if @a is greater than @b. If @a and @b are
122 * equivalent, then it does not matter what this function returns.
123 */
124static void list_sort(void *priv, struct list_head *head,
125 int (*cmp)(void *priv, struct list_head *a,
126 struct list_head *b))
127{
128 struct list_head *p, *q, *e, *list, *tail, *oldhead;
129 int insize, nmerges, psize, qsize, i;
130
131 if (list_empty(head))
132 return;
133
134 list = head->next;
135 list_del(head);
136 insize = 1;
137 for (;;) {
138 p = oldhead = list;
139 list = tail = NULL;
140 nmerges = 0;
141
142 while (p) {
143 nmerges++;
144 q = p;
145 psize = 0;
146 for (i = 0; i < insize; i++) {
147 psize++;
148 q = q->next == oldhead ? NULL : q->next;
149 if (!q)
150 break;
151 }
152
153 qsize = insize;
154 while (psize > 0 || (qsize > 0 && q)) {
155 if (!psize) {
156 e = q;
157 q = q->next;
158 qsize--;
159 if (q == oldhead)
160 q = NULL;
161 } else if (!qsize || !q) {
162 e = p;
163 p = p->next;
164 psize--;
165 if (p == oldhead)
166 p = NULL;
167 } else if (cmp(priv, p, q) <= 0) {
168 e = p;
169 p = p->next;
170 psize--;
171 if (p == oldhead)
172 p = NULL;
173 } else {
174 e = q;
175 q = q->next;
176 qsize--;
177 if (q == oldhead)
178 q = NULL;
179 }
180 if (tail)
181 tail->next = e;
182 else
183 list = e;
184 e->prev = tail;
185 tail = e;
186 }
187 p = q;
188 }
189
190 tail->next = list;
191 list->prev = tail;
192
193 if (nmerges <= 1)
194 break;
195
196 insize *= 2;
197 }
198
199 head->next = list;
200 head->prev = list->prev;
201 list->prev->next = head;
202 list->prev = head;
203}
204
205/**
206 * data_nodes_cmp - compare 2 data nodes. 112 * data_nodes_cmp - compare 2 data nodes.
207 * @priv: UBIFS file-system description object 113 * @priv: UBIFS file-system description object
208 * @a: first data node 114 * @a: first data node