[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / ceph / pagelist.c

#include <linux/module.h>
#include <linux/gfp.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/ceph/pagelist.h>

static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
{
	if (pl->mapped_tail) {
		struct page *page = list_entry(pl->head.prev, struct page, lru);
		kunmap(page);
		pl->mapped_tail = NULL;
	}
}

int ceph_pagelist_release(struct ceph_pagelist *pl)
{
	ceph_pagelist_unmap_tail(pl);
	while (!list_empty(&pl->head)) {
		struct page *page = list_first_entry(&pl->head, struct page,
						     lru);
		list_del(&page->lru);
		__free_page(page);
	}
	ceph_pagelist_free_reserve(pl);
	return 0;
}
EXPORT_SYMBOL(ceph_pagelist_release);

static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
{
	struct page *page;

	if (!pl->num_pages_free) {
		page = __page_cache_alloc(GFP_NOFS);
	} else {
		page = list_first_entry(&pl->free_list, struct page, lru);
		list_del(&page->lru);
		--pl->num_pages_free;
	}
	if (!page)
		return -ENOMEM;
	pl->room += PAGE_SIZE;
	ceph_pagelist_unmap_tail(pl);
	list_add_tail(&page->lru, &pl->head);
	pl->mapped_tail = kmap(page);
	return 0;
}

int ceph_pagelist_append(struct ceph_pagelist *pl, const void *buf, size_t len)
{
	while (pl->room < len) {
		size_t bit = pl->room;
		int ret;

		memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
		       buf, bit);
		pl->length += bit;
		pl->room -= bit;
		buf += bit;
		len -= bit;
		ret = ceph_pagelist_addpage(pl);
		if (ret)
			return ret;
	}

	memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
	pl->length += len;
	pl->room -= len;
	return 0;
}
EXPORT_SYMBOL(ceph_pagelist_append);

/* Allocate enough pages for a pagelist to append the given amount
 * of data without without allocating.
 * Returns: 0 on success, -ENOMEM on error.
 */
int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space)
{
	if (space <= pl->room)
		return 0;
	space -= pl->room;
	space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT;   /* conv to num pages */

	while (space > pl->num_pages_free) {
		struct page *page = __page_cache_alloc(GFP_NOFS);
		if (!page)
			return -ENOMEM;
		list_add_tail(&page->lru, &pl->free_list);
		++pl->num_pages_free;
	}
	return 0;
}
EXPORT_SYMBOL(ceph_pagelist_reserve);

/* Free any pages that have been preallocated. */
int ceph_pagelist_free_reserve(struct ceph_pagelist *pl)
{
	while (!list_empty(&pl->free_list)) {
		struct page *page = list_first_entry(&pl->free_list,
						     struct page, lru);
		list_del(&page->lru);
		__free_page(page);
		--pl->num_pages_free;
	}
	BUG_ON(pl->num_pages_free);
	return 0;
}
EXPORT_SYMBOL(ceph_pagelist_free_reserve);

/* Create a truncation point. */
void ceph_pagelist_set_cursor(struct ceph_pagelist *pl,
			      struct ceph_pagelist_cursor *c)
{
	c->pl = pl;
	c->page_lru = pl->head.prev;
	c->room = pl->room;
}
EXPORT_SYMBOL(ceph_pagelist_set_cursor);

/* Truncate a pagelist to the given point. Move extra pages to reserve.
 * This won't sleep.
 * Returns: 0 on success,
 *          -EINVAL if the pagelist doesn't match the trunc point pagelist
 */
int ceph_pagelist_truncate(struct ceph_pagelist *pl,
			   struct ceph_pagelist_cursor *c)
{
	struct page *page;

	if (pl != c->pl)
		return -EINVAL;
	ceph_pagelist_unmap_tail(pl);
	while (pl->head.prev != c->page_lru) {
		page = list_entry(pl->head.prev, struct page, lru);
		/* move from pagelist to reserve */
		list_move_tail(&page->lru, &pl->free_list);
		++pl->num_pages_free;
	}
	pl->room = c->room;
	if (!list_empty(&pl->head)) {
		page = list_entry(pl->head.prev, struct page, lru);
		pl->mapped_tail = kmap(page);
	}
	return 0;
}
EXPORT_SYMBOL(ceph_pagelist_truncate);
Commit	Line	Data
3d14c5d2	1	#include <linux/module.h>
5a0e3ad6	2	#include <linux/gfp.h>
58bb3b37 SW	3	#include <linux/pagemap.h>
58bb3b37 SW	4	#include <linux/highmem.h>
3d14c5d2	5	#include <linux/ceph/pagelist.h>
58bb3b37	6
3d4401d9 YS	7	static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
3d4401d9 YS	8	{
ac0b74d8 GF	9	if (pl->mapped_tail) {
	10	struct page *page = list_entry(pl->head.prev, struct page, lru);
	11	kunmap(page);
	12	pl->mapped_tail = NULL;
	13	}
3d4401d9 YS	14	}
3d4401d9 YS	15
58bb3b37 SW	16	int ceph_pagelist_release(struct ceph_pagelist *pl)
58bb3b37 SW	17	{
ac0b74d8	18	ceph_pagelist_unmap_tail(pl);
58bb3b37 SW	19	while (!list_empty(&pl->head)) {
	20	struct page *page = list_first_entry(&pl->head, struct page,
	21	lru);
	22	list_del(&page->lru);
	23	__free_page(page);
	24	}
ac0b74d8	25	ceph_pagelist_free_reserve(pl);
58bb3b37 SW	26	return 0;
58bb3b37 SW	27	}
3d14c5d2	28	EXPORT_SYMBOL(ceph_pagelist_release);
58bb3b37 SW	29
	30	static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
	31	{
ac0b74d8 GF	32	struct page *page;
	33
	34	if (!pl->num_pages_free) {
	35	page = __page_cache_alloc(GFP_NOFS);
	36	} else {
	37	page = list_first_entry(&pl->free_list, struct page, lru);
	38	list_del(&page->lru);
240634e9	39	--pl->num_pages_free;
ac0b74d8	40	}
58bb3b37 SW	41	if (!page)
	42	return -ENOMEM;
	43	pl->room += PAGE_SIZE;
ac0b74d8	44	ceph_pagelist_unmap_tail(pl);
58bb3b37	45	list_add_tail(&page->lru, &pl->head);
58bb3b37 SW	46	pl->mapped_tail = kmap(page);
	47	return 0;
	48	}
	49
68b4476b	50	int ceph_pagelist_append(struct ceph_pagelist pl, const void buf, size_t len)
58bb3b37 SW	51	{
	52	while (pl->room < len) {
	53	size_t bit = pl->room;
	54	int ret;
	55
	56	memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK),
	57	buf, bit);
	58	pl->length += bit;
	59	pl->room -= bit;
	60	buf += bit;
	61	len -= bit;
	62	ret = ceph_pagelist_addpage(pl);
	63	if (ret)
	64	return ret;
	65	}
	66
	67	memcpy(pl->mapped_tail + (pl->length & ~PAGE_CACHE_MASK), buf, len);
	68	pl->length += len;
	69	pl->room -= len;
	70	return 0;
	71	}
3d14c5d2	72	EXPORT_SYMBOL(ceph_pagelist_append);
ac0b74d8	73
ae86b9e3	74	/* Allocate enough pages for a pagelist to append the given amount
ac0b74d8 GF	75	* of data without without allocating.
	76	* Returns: 0 on success, -ENOMEM on error.
	77	*/
	78	int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space)
	79	{
	80	if (space <= pl->room)
	81	return 0;
	82	space -= pl->room;
	83	space = (space + PAGE_SIZE - 1) >> PAGE_SHIFT; /* conv to num pages */
	84
	85	while (space > pl->num_pages_free) {
	86	struct page *page = __page_cache_alloc(GFP_NOFS);
	87	if (!page)
	88	return -ENOMEM;
	89	list_add_tail(&page->lru, &pl->free_list);
	90	++pl->num_pages_free;
	91	}
	92	return 0;
	93	}
	94	EXPORT_SYMBOL(ceph_pagelist_reserve);
	95
ae86b9e3	96	/* Free any pages that have been preallocated. */
ac0b74d8 GF	97	int ceph_pagelist_free_reserve(struct ceph_pagelist *pl)
	98	{
	99	while (!list_empty(&pl->free_list)) {
	100	struct page *page = list_first_entry(&pl->free_list,
	101	struct page, lru);
	102	list_del(&page->lru);
	103	__free_page(page);
	104	--pl->num_pages_free;
	105	}
	106	BUG_ON(pl->num_pages_free);
	107	return 0;
	108	}
	109	EXPORT_SYMBOL(ceph_pagelist_free_reserve);
	110
ae86b9e3	111	/* Create a truncation point. */
ac0b74d8 GF	112	void ceph_pagelist_set_cursor(struct ceph_pagelist *pl,
	113	struct ceph_pagelist_cursor *c)
	114	{
	115	c->pl = pl;
	116	c->page_lru = pl->head.prev;
	117	c->room = pl->room;
	118	}
	119	EXPORT_SYMBOL(ceph_pagelist_set_cursor);
	120
ae86b9e3	121	/* Truncate a pagelist to the given point. Move extra pages to reserve.
ac0b74d8 GF	122	* This won't sleep.
	123	* Returns: 0 on success,
	124	* -EINVAL if the pagelist doesn't match the trunc point pagelist
	125	*/
	126	int ceph_pagelist_truncate(struct ceph_pagelist *pl,
	127	struct ceph_pagelist_cursor *c)
	128	{
	129	struct page *page;
	130
	131	if (pl != c->pl)
	132	return -EINVAL;
	133	ceph_pagelist_unmap_tail(pl);
	134	while (pl->head.prev != c->page_lru) {
	135	page = list_entry(pl->head.prev, struct page, lru);
cc4829e5 WY	136	/* move from pagelist to reserve */
cc4829e5 WY	137	list_move_tail(&page->lru, &pl->free_list);
ac0b74d8 GF	138	++pl->num_pages_free;
	139	}
	140	pl->room = c->room;
	141	if (!list_empty(&pl->head)) {
	142	page = list_entry(pl->head.prev, struct page, lru);
	143	pl->mapped_tail = kmap(page);
	144	}
	145	return 0;
	146	}
	147	EXPORT_SYMBOL(ceph_pagelist_truncate);