Commit | Line | Data |
---|---|---|
3d14c5d2 | 1 | #include <linux/module.h> |
5a0e3ad6 | 2 | #include <linux/gfp.h> |
e4339d28 | 3 | #include <linux/slab.h> |
58bb3b37 SW |
4 | #include <linux/pagemap.h> |
5 | #include <linux/highmem.h> | |
3d14c5d2 | 6 | #include <linux/ceph/pagelist.h> |
58bb3b37 | 7 | |
3d4401d9 YS |
8 | static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl) |
9 | { | |
ac0b74d8 GF |
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 | } | |
3d4401d9 YS |
15 | } |
16 | ||
e4339d28 | 17 | void ceph_pagelist_release(struct ceph_pagelist *pl) |
58bb3b37 | 18 | { |
e4339d28 YZ |
19 | if (!atomic_dec_and_test(&pl->refcnt)) |
20 | return; | |
ac0b74d8 | 21 | ceph_pagelist_unmap_tail(pl); |
58bb3b37 SW |
22 | while (!list_empty(&pl->head)) { |
23 | struct page *page = list_first_entry(&pl->head, struct page, | |
24 | lru); | |
25 | list_del(&page->lru); | |
26 | __free_page(page); | |
27 | } | |
ac0b74d8 | 28 | ceph_pagelist_free_reserve(pl); |
e4339d28 | 29 | kfree(pl); |
58bb3b37 | 30 | } |
3d14c5d2 | 31 | EXPORT_SYMBOL(ceph_pagelist_release); |
58bb3b37 SW |
32 | |
33 | static int ceph_pagelist_addpage(struct ceph_pagelist *pl) | |
34 | { | |
ac0b74d8 GF |
35 | struct page *page; |
36 | ||
37 | if (!pl->num_pages_free) { | |
38 | page = __page_cache_alloc(GFP_NOFS); | |
39 | } else { | |
40 | page = list_first_entry(&pl->free_list, struct page, lru); | |
41 | list_del(&page->lru); | |
240634e9 | 42 | --pl->num_pages_free; |
ac0b74d8 | 43 | } |
58bb3b37 SW |
44 | if (!page) |
45 | return -ENOMEM; | |
46 | pl->room += PAGE_SIZE; | |
ac0b74d8 | 47 | ceph_pagelist_unmap_tail(pl); |
58bb3b37 | 48 | list_add_tail(&page->lru, &pl->head); |
58bb3b37 SW |
49 | pl->mapped_tail = kmap(page); |
50 | return 0; | |
51 | } | |
52 | ||
68b4476b | 53 | int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len) |
58bb3b37 SW |
54 | { |
55 | while (pl->room < len) { | |
56 | size_t bit = pl->room; | |
57 | int ret; | |
58 | ||
59 | memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), | |
60 | buf, bit); | |
61 | pl->length += bit; | |
62 | pl->room -= bit; | |
63 | buf += bit; | |
64 | len -= bit; | |
65 | ret = ceph_pagelist_addpage(pl); | |
66 | if (ret) | |
67 | return ret; | |
68 | } | |
69 | ||
70 | memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len); | |
71 | pl->length += len; | |
72 | pl->room -= len; | |
73 | return 0; | |
74 | } | |
3d14c5d2 | 75 | EXPORT_SYMBOL(ceph_pagelist_append); |
ac0b74d8 | 76 | |
ae86b9e3 | 77 | /* Allocate enough pages for a pagelist to append the given amount |
ac0b74d8 GF |
78 | * of data without without allocating. |
79 | * Returns: 0 on success, -ENOMEM on error. | |
80 | */ | |
81 | int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space) | |
82 | { | |
83 | if (space <= pl->room) | |
84 | return 0; | |
85 | space -= pl->room; | |
86 | space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT; /* conv to num pages */ | |
87 | ||
88 | while (space > pl->num_pages_free) { | |
89 | struct page *page = __page_cache_alloc(GFP_NOFS); | |
90 | if (!page) | |
91 | return -ENOMEM; | |
92 | list_add_tail(&page->lru, &pl->free_list); | |
93 | ++pl->num_pages_free; | |
94 | } | |
95 | return 0; | |
96 | } | |
97 | EXPORT_SYMBOL(ceph_pagelist_reserve); | |
98 | ||
ae86b9e3 | 99 | /* Free any pages that have been preallocated. */ |
ac0b74d8 GF |
100 | int ceph_pagelist_free_reserve(struct ceph_pagelist *pl) |
101 | { | |
102 | while (!list_empty(&pl->free_list)) { | |
103 | struct page *page = list_first_entry(&pl->free_list, | |
104 | struct page, lru); | |
105 | list_del(&page->lru); | |
106 | __free_page(page); | |
107 | --pl->num_pages_free; | |
108 | } | |
109 | BUG_ON(pl->num_pages_free); | |
110 | return 0; | |
111 | } | |
112 | EXPORT_SYMBOL(ceph_pagelist_free_reserve); | |
113 | ||
ae86b9e3 | 114 | /* Create a truncation point. */ |
ac0b74d8 GF |
115 | void ceph_pagelist_set_cursor(struct ceph_pagelist *pl, |
116 | struct ceph_pagelist_cursor *c) | |
117 | { | |
118 | c->pl = pl; | |
119 | c->page_lru = pl->head.prev; | |
120 | c->room = pl->room; | |
121 | } | |
122 | EXPORT_SYMBOL(ceph_pagelist_set_cursor); | |
123 | ||
ae86b9e3 | 124 | /* Truncate a pagelist to the given point. Move extra pages to reserve. |
ac0b74d8 GF |
125 | * This won't sleep. |
126 | * Returns: 0 on success, | |
127 | * -EINVAL if the pagelist doesn't match the trunc point pagelist | |
128 | */ | |
129 | int ceph_pagelist_truncate(struct ceph_pagelist *pl, | |
130 | struct ceph_pagelist_cursor *c) | |
131 | { | |
132 | struct page *page; | |
133 | ||
134 | if (pl != c->pl) | |
135 | return -EINVAL; | |
136 | ceph_pagelist_unmap_tail(pl); | |
137 | while (pl->head.prev != c->page_lru) { | |
138 | page = list_entry(pl->head.prev, struct page, lru); | |
cc4829e5 WY |
139 | /* move from pagelist to reserve */ |
140 | list_move_tail(&page->lru, &pl->free_list); | |
ac0b74d8 GF |
141 | ++pl->num_pages_free; |
142 | } | |
143 | pl->room = c->room; | |
144 | if (!list_empty(&pl->head)) { | |
145 | page = list_entry(pl->head.prev, struct page, lru); | |
146 | pl->mapped_tail = kmap(page); | |
147 | } | |
148 | return 0; | |
149 | } | |
150 | EXPORT_SYMBOL(ceph_pagelist_truncate); |