net/ceph/pagelist.c

11 	struct ceph_pagelist *pl;
13 	pl = kmalloc(sizeof(*pl), gfp_flags);
14 	if (!pl)
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);
25 	return pl;
29 static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
31 	if (pl->mapped_tail) {
32 		struct page *page = list_entry(pl->head.prev, struct page, lru);
34 		pl->mapped_tail = NULL;
38 void ceph_pagelist_release(struct ceph_pagelist *pl)
40 	if (!refcount_dec_and_test(&pl->refcnt))
42 	ceph_pagelist_unmap_tail(pl);
43 	while (!list_empty(&pl->head)) {
44 		struct page *page = list_first_entry(&pl->head, struct page,
49 	ceph_pagelist_free_reserve(pl);
50 	kfree(pl);
54 static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
58 	if (!pl->num_pages_free) {
61 		page = list_first_entry(&pl->free_list, struct page, lru);
63 		--pl->num_pages_free;
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);
74 int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
76 	while (pl->room < len) {
77 		size_t bit = pl->room;
80 		memcpy(pl->mapped_tail + (pl->length & ~PAGE_MASK),
82 		pl->length += bit;
83 		pl->room -= bit;
86 		ret = ceph_pagelist_addpage(pl);
91 	memcpy(pl->mapped_tail + (pl->length & ~PAGE_MASK), buf, len);
92 	pl->length += len;
93 	pl->room -= len;
102 int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space)
104 	if (space <= pl->room)
106 	space -= pl->room;
109 	while (space > pl->num_pages_free) {
113 		list_add_tail(&page->lru, &pl->free_list);
114 		++pl->num_pages_free;
121 int ceph_pagelist_free_reserve(struct ceph_pagelist *pl)
123 	while (!list_empty(&pl->free_list)) {
124 		struct page *page = list_first_entry(&pl->free_list,
128 		--pl->num_pages_free;
130 	BUG_ON(pl->num_pages_free);
136 void ceph_pagelist_set_cursor(struct ceph_pagelist *pl,
139 	c->pl = pl;
140 	c->page_lru = pl->head.prev;
141 	c->room = pl->room;
150 int ceph_pagelist_truncate(struct ceph_pagelist *pl,
155 	if (pl != c->pl)
157 	ceph_pagelist_unmap_tail(pl);
158 	while (pl->head.prev != c->page_lru) {
159 		page = list_entry(pl->head.prev, struct page, lru);
161 		list_move_tail(&page->lru, &pl->free_list);
162 		++pl->num_pages_free;
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);