blob: 13cb409a7bba13a2dd248c7a7dd25b9c00253370 [file] [log] [blame]
Sage Weil58bb3b32009-12-23 12:12:31 -08001
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -07002#include <linux/module.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09003#include <linux/gfp.h>
Sage Weil58bb3b32009-12-23 12:12:31 -08004#include <linux/pagemap.h>
5#include <linux/highmem.h>
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -07006#include <linux/ceph/pagelist.h>
Sage Weil58bb3b32009-12-23 12:12:31 -08007
Yehuda Sadeh3d4401d2010-09-03 12:57:11 -07008static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
9{
Greg Farnumac0b74d2010-09-17 10:10:55 -070010 if (pl->mapped_tail) {
11 struct page *page = list_entry(pl->head.prev, struct page, lru);
12 kunmap(page);
13 pl->mapped_tail = NULL;
14 }
Yehuda Sadeh3d4401d2010-09-03 12:57:11 -070015}
16
Sage Weil58bb3b32009-12-23 12:12:31 -080017int ceph_pagelist_release(struct ceph_pagelist *pl)
18{
Greg Farnumac0b74d2010-09-17 10:10:55 -070019 ceph_pagelist_unmap_tail(pl);
Sage Weil58bb3b32009-12-23 12:12:31 -080020 while (!list_empty(&pl->head)) {
21 struct page *page = list_first_entry(&pl->head, struct page,
22 lru);
23 list_del(&page->lru);
24 __free_page(page);
25 }
Greg Farnumac0b74d2010-09-17 10:10:55 -070026 ceph_pagelist_free_reserve(pl);
Sage Weil58bb3b32009-12-23 12:12:31 -080027 return 0;
28}
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -070029EXPORT_SYMBOL(ceph_pagelist_release);
Sage Weil58bb3b32009-12-23 12:12:31 -080030
31static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
32{
Greg Farnumac0b74d2010-09-17 10:10:55 -070033 struct page *page;
34
35 if (!pl->num_pages_free) {
36 page = __page_cache_alloc(GFP_NOFS);
37 } else {
38 page = list_first_entry(&pl->free_list, struct page, lru);
39 list_del(&page->lru);
Sage Weil240634e2010-10-05 12:03:23 -070040 --pl->num_pages_free;
Greg Farnumac0b74d2010-09-17 10:10:55 -070041 }
Sage Weil58bb3b32009-12-23 12:12:31 -080042 if (!page)
43 return -ENOMEM;
44 pl->room += PAGE_SIZE;
Greg Farnumac0b74d2010-09-17 10:10:55 -070045 ceph_pagelist_unmap_tail(pl);
Sage Weil58bb3b32009-12-23 12:12:31 -080046 list_add_tail(&page->lru, &pl->head);
Sage Weil58bb3b32009-12-23 12:12:31 -080047 pl->mapped_tail = kmap(page);
48 return 0;
49}
50
Yehuda Sadeh68b44762010-04-06 15:01:27 -070051int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
Sage Weil58bb3b32009-12-23 12:12:31 -080052{
53 while (pl->room < len) {
54 size_t bit = pl->room;
55 int ret;
56
57 memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
58 buf, bit);
59 pl->length += bit;
60 pl->room -= bit;
61 buf += bit;
62 len -= bit;
63 ret = ceph_pagelist_addpage(pl);
64 if (ret)
65 return ret;
66 }
67
68 memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
69 pl->length += len;
70 pl->room -= len;
71 return 0;
72}
Yehuda Sadeh3d14c5d2010-04-06 15:14:15 -070073EXPORT_SYMBOL(ceph_pagelist_append);
Greg Farnumac0b74d2010-09-17 10:10:55 -070074
75/**
76 * Allocate enough pages for a pagelist to append the given amount
77 * of data without without allocating.
78 * Returns: 0 on success, -ENOMEM on error.
79 */
80int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space)
81{
82 if (space <= pl->room)
83 return 0;
84 space -= pl->room;
85 space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT; /* conv to num pages */
86
87 while (space > pl->num_pages_free) {
88 struct page *page = __page_cache_alloc(GFP_NOFS);
89 if (!page)
90 return -ENOMEM;
91 list_add_tail(&page->lru, &pl->free_list);
92 ++pl->num_pages_free;
93 }
94 return 0;
95}
96EXPORT_SYMBOL(ceph_pagelist_reserve);
97
98/**
99 * Free any pages that have been preallocated.
100 */
101int ceph_pagelist_free_reserve(struct ceph_pagelist *pl)
102{
103 while (!list_empty(&pl->free_list)) {
104 struct page *page = list_first_entry(&pl->free_list,
105 struct page, lru);
106 list_del(&page->lru);
107 __free_page(page);
108 --pl->num_pages_free;
109 }
110 BUG_ON(pl->num_pages_free);
111 return 0;
112}
113EXPORT_SYMBOL(ceph_pagelist_free_reserve);
114
115/**
116 * Create a truncation point.
117 */
118void ceph_pagelist_set_cursor(struct ceph_pagelist *pl,
119 struct ceph_pagelist_cursor *c)
120{
121 c->pl = pl;
122 c->page_lru = pl->head.prev;
123 c->room = pl->room;
124}
125EXPORT_SYMBOL(ceph_pagelist_set_cursor);
126
127/**
128 * Truncate a pagelist to the given point. Move extra pages to reserve.
129 * This won't sleep.
130 * Returns: 0 on success,
131 * -EINVAL if the pagelist doesn't match the trunc point pagelist
132 */
133int ceph_pagelist_truncate(struct ceph_pagelist *pl,
134 struct ceph_pagelist_cursor *c)
135{
136 struct page *page;
137
138 if (pl != c->pl)
139 return -EINVAL;
140 ceph_pagelist_unmap_tail(pl);
141 while (pl->head.prev != c->page_lru) {
142 page = list_entry(pl->head.prev, struct page, lru);
143 list_del(&page->lru); /* remove from pagelist */
144 list_add_tail(&page->lru, &pl->free_list); /* add to reserve */
145 ++pl->num_pages_free;
146 }
147 pl->room = c->room;
148 if (!list_empty(&pl->head)) {
149 page = list_entry(pl->head.prev, struct page, lru);
150 pl->mapped_tail = kmap(page);
151 }
152 return 0;
153}
154EXPORT_SYMBOL(ceph_pagelist_truncate);