2 #include <linux/module.h>
4 #include <linux/pagemap.h>
5 #include <linux/highmem.h>
6 #include <linux/ceph/pagelist.h>
8 static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
10 if (pl->mapped_tail) {
11 struct page *page = list_entry(pl->head.prev, struct page, lru);
13 pl->mapped_tail = NULL;
17 int ceph_pagelist_release(struct ceph_pagelist *pl)
19 ceph_pagelist_unmap_tail(pl);
20 while (!list_empty(&pl->head)) {
21 struct page *page = list_first_entry(&pl->head, struct page,
26 ceph_pagelist_free_reserve(pl);
29 EXPORT_SYMBOL(ceph_pagelist_release);
31 static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
35 if (!pl->num_pages_free) {
36 page = __page_cache_alloc(GFP_NOFS);
38 page = list_first_entry(&pl->free_list, struct page, lru);
43 pl->room += PAGE_SIZE;
44 ceph_pagelist_unmap_tail(pl);
45 list_add_tail(&page->lru, &pl->head);
46 pl->mapped_tail = kmap(page);
50 int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
52 while (pl->room < len) {
53 size_t bit = pl->room;
56 memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
62 ret = ceph_pagelist_addpage(pl);
67 memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
72 EXPORT_SYMBOL(ceph_pagelist_append);
75 * Allocate enough pages for a pagelist to append the given amount
76 * of data without without allocating.
77 * Returns: 0 on success, -ENOMEM on error.
79 int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space)
81 if (space <= pl->room)
84 space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT; /* conv to num pages */
86 while (space > pl->num_pages_free) {
87 struct page *page = __page_cache_alloc(GFP_NOFS);
90 list_add_tail(&page->lru, &pl->free_list);
95 EXPORT_SYMBOL(ceph_pagelist_reserve);
98 * Free any pages that have been preallocated.
100 int ceph_pagelist_free_reserve(struct ceph_pagelist *pl)
102 while (!list_empty(&pl->free_list)) {
103 struct page *page = list_first_entry(&pl->free_list,
105 list_del(&page->lru);
107 --pl->num_pages_free;
109 BUG_ON(pl->num_pages_free);
112 EXPORT_SYMBOL(ceph_pagelist_free_reserve);
115 * Create a truncation point.
117 void ceph_pagelist_set_cursor(struct ceph_pagelist *pl,
118 struct ceph_pagelist_cursor *c)
121 c->page_lru = pl->head.prev;
124 EXPORT_SYMBOL(ceph_pagelist_set_cursor);
127 * Truncate a pagelist to the given point. Move extra pages to reserve.
129 * Returns: 0 on success,
130 * -EINVAL if the pagelist doesn't match the trunc point pagelist
132 int ceph_pagelist_truncate(struct ceph_pagelist *pl,
133 struct ceph_pagelist_cursor *c)
139 ceph_pagelist_unmap_tail(pl);
140 while (pl->head.prev != c->page_lru) {
141 page = list_entry(pl->head.prev, struct page, lru);
142 list_del(&page->lru); /* remove from pagelist */
143 list_add_tail(&page->lru, &pl->free_list); /* add to reserve */
144 ++pl->num_pages_free;
147 if (!list_empty(&pl->head)) {
148 page = list_entry(pl->head.prev, struct page, lru);
149 pl->mapped_tail = kmap(page);
153 EXPORT_SYMBOL(ceph_pagelist_truncate);