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1
2#include <linux/module.h>
3#include <linux/gfp.h>
4#include <linux/pagemap.h>
5#include <linux/highmem.h>
6#include <linux/ceph/pagelist.h>
7
8static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
9{
10 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 }
15}
16
17int ceph_pagelist_release(struct ceph_pagelist *pl)
18{
19 ceph_pagelist_unmap_tail(pl);
20 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 }
26 ceph_pagelist_free_reserve(pl);
27 return 0;
28}
29EXPORT_SYMBOL(ceph_pagelist_release);
30
31static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
32{
33 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);
40 --pl->num_pages_free;
41 }
42 if (!page)
43 return -ENOMEM;
44 pl->room += PAGE_SIZE;
45 ceph_pagelist_unmap_tail(pl);
46 list_add_tail(&page->lru, &pl->head);
47 pl->mapped_tail = kmap(page);
48 return 0;
49}
50
51int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
52{
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}
73EXPORT_SYMBOL(ceph_pagelist_append);
74
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);
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/module.h>
3#include <linux/gfp.h>
4#include <linux/slab.h>
5#include <linux/pagemap.h>
6#include <linux/highmem.h>
7#include <linux/ceph/pagelist.h>
8
9struct ceph_pagelist *ceph_pagelist_alloc(gfp_t gfp_flags)
10{
11 struct ceph_pagelist *pl;
12
13 pl = kmalloc(sizeof(*pl), gfp_flags);
14 if (!pl)
15 return NULL;
16
17 INIT_LIST_HEAD(&pl->head);
18 pl->mapped_tail = NULL;
19 pl->length = 0;
20 pl->room = 0;
21 INIT_LIST_HEAD(&pl->free_list);
22 pl->num_pages_free = 0;
23 refcount_set(&pl->refcnt, 1);
24
25 return pl;
26}
27EXPORT_SYMBOL(ceph_pagelist_alloc);
28
29static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
30{
31 if (pl->mapped_tail) {
32 struct page *page = list_entry(pl->head.prev, struct page, lru);
33 kunmap(page);
34 pl->mapped_tail = NULL;
35 }
36}
37
38void ceph_pagelist_release(struct ceph_pagelist *pl)
39{
40 if (!refcount_dec_and_test(&pl->refcnt))
41 return;
42 ceph_pagelist_unmap_tail(pl);
43 while (!list_empty(&pl->head)) {
44 struct page *page = list_first_entry(&pl->head, struct page,
45 lru);
46 list_del(&page->lru);
47 __free_page(page);
48 }
49 ceph_pagelist_free_reserve(pl);
50 kfree(pl);
51}
52EXPORT_SYMBOL(ceph_pagelist_release);
53
54static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
55{
56 struct page *page;
57
58 if (!pl->num_pages_free) {
59 page = __page_cache_alloc(GFP_NOFS);
60 } else {
61 page = list_first_entry(&pl->free_list, struct page, lru);
62 list_del(&page->lru);
63 --pl->num_pages_free;
64 }
65 if (!page)
66 return -ENOMEM;
67 pl->room += PAGE_SIZE;
68 ceph_pagelist_unmap_tail(pl);
69 list_add_tail(&page->lru, &pl->head);
70 pl->mapped_tail = kmap(page);
71 return 0;
72}
73
74int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
75{
76 while (pl->room < len) {
77 size_t bit = pl->room;
78 int ret;
79
80 memcpy(pl->mapped_tail + (pl->length & ~PAGE_MASK),
81 buf, bit);
82 pl->length += bit;
83 pl->room -= bit;
84 buf += bit;
85 len -= bit;
86 ret = ceph_pagelist_addpage(pl);
87 if (ret)
88 return ret;
89 }
90
91 memcpy(pl->mapped_tail + (pl->length & ~PAGE_MASK), buf, len);
92 pl->length += len;
93 pl->room -= len;
94 return 0;
95}
96EXPORT_SYMBOL(ceph_pagelist_append);
97
98/* Allocate enough pages for a pagelist to append the given amount
99 * of data without allocating.
100 * Returns: 0 on success, -ENOMEM on error.
101 */
102int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space)
103{
104 if (space <= pl->room)
105 return 0;
106 space -= pl->room;
107 space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT; /* conv to num pages */
108
109 while (space > pl->num_pages_free) {
110 struct page *page = __page_cache_alloc(GFP_NOFS);
111 if (!page)
112 return -ENOMEM;
113 list_add_tail(&page->lru, &pl->free_list);
114 ++pl->num_pages_free;
115 }
116 return 0;
117}
118EXPORT_SYMBOL(ceph_pagelist_reserve);
119
120/* Free any pages that have been preallocated. */
121int ceph_pagelist_free_reserve(struct ceph_pagelist *pl)
122{
123 while (!list_empty(&pl->free_list)) {
124 struct page *page = list_first_entry(&pl->free_list,
125 struct page, lru);
126 list_del(&page->lru);
127 __free_page(page);
128 --pl->num_pages_free;
129 }
130 BUG_ON(pl->num_pages_free);
131 return 0;
132}
133EXPORT_SYMBOL(ceph_pagelist_free_reserve);
134
135/* Create a truncation point. */
136void ceph_pagelist_set_cursor(struct ceph_pagelist *pl,
137 struct ceph_pagelist_cursor *c)
138{
139 c->pl = pl;
140 c->page_lru = pl->head.prev;
141 c->room = pl->room;
142}
143EXPORT_SYMBOL(ceph_pagelist_set_cursor);
144
145/* Truncate a pagelist to the given point. Move extra pages to reserve.
146 * This won't sleep.
147 * Returns: 0 on success,
148 * -EINVAL if the pagelist doesn't match the trunc point pagelist
149 */
150int ceph_pagelist_truncate(struct ceph_pagelist *pl,
151 struct ceph_pagelist_cursor *c)
152{
153 struct page *page;
154
155 if (pl != c->pl)
156 return -EINVAL;
157 ceph_pagelist_unmap_tail(pl);
158 while (pl->head.prev != c->page_lru) {
159 page = list_entry(pl->head.prev, struct page, lru);
160 /* move from pagelist to reserve */
161 list_move_tail(&page->lru, &pl->free_list);
162 ++pl->num_pages_free;
163 }
164 pl->room = c->room;
165 if (!list_empty(&pl->head)) {
166 page = list_entry(pl->head.prev, struct page, lru);
167 pl->mapped_tail = kmap(page);
168 }
169 return 0;
170}
171EXPORT_SYMBOL(ceph_pagelist_truncate);