[linux.git] / net / ceph / pagelist.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/module.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/ceph/pagelist.h>

struct ceph_pagelist *ceph_pagelist_alloc(gfp_t gfp_flags)
{
	struct ceph_pagelist *pl;

	pl = kmalloc(sizeof(*pl), gfp_flags);
	if (!pl)
		return NULL;

	INIT_LIST_HEAD(&pl->head);
	pl->mapped_tail = NULL;
	pl->length = 0;
	pl->room = 0;
	INIT_LIST_HEAD(&pl->free_list);
	pl->num_pages_free = 0;
	refcount_set(&pl->refcnt, 1);

	return pl;
}
EXPORT_SYMBOL(ceph_pagelist_alloc);

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;
	}
}

void ceph_pagelist_release(struct ceph_pagelist *pl)
{
	if (!refcount_dec_and_test(&pl->refcnt))
		return;
	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);
	kfree(pl);
}
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_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_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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
3d14c5d2	2	#include <linux/module.h>
5a0e3ad6	3	#include <linux/gfp.h>
e4339d28	4	#include <linux/slab.h>
58bb3b37 SW	5	#include <linux/pagemap.h>
58bb3b37 SW	6	#include <linux/highmem.h>
3d14c5d2	7	#include <linux/ceph/pagelist.h>
58bb3b37	8
33165d47 ID	9	struct 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	}
	27	EXPORT_SYMBOL(ceph_pagelist_alloc);
	28
3d4401d9 YS	29	static void ceph_pagelist_unmap_tail(struct ceph_pagelist *pl)
3d4401d9 YS	30	{
ac0b74d8 GF	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	}
3d4401d9 YS	36	}
3d4401d9 YS	37
e4339d28	38	void ceph_pagelist_release(struct ceph_pagelist *pl)
58bb3b37	39	{
0e1a5ee6	40	if (!refcount_dec_and_test(&pl->refcnt))
e4339d28	41	return;
ac0b74d8	42	ceph_pagelist_unmap_tail(pl);
58bb3b37 SW	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	}
ac0b74d8	49	ceph_pagelist_free_reserve(pl);
e4339d28	50	kfree(pl);
58bb3b37	51	}
3d14c5d2	52	EXPORT_SYMBOL(ceph_pagelist_release);
58bb3b37 SW	53
	54	static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
	55	{
ac0b74d8 GF	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);
240634e9	63	--pl->num_pages_free;
ac0b74d8	64	}
58bb3b37 SW	65	if (!page)
	66	return -ENOMEM;
	67	pl->room += PAGE_SIZE;
ac0b74d8	68	ceph_pagelist_unmap_tail(pl);
58bb3b37	69	list_add_tail(&page->lru, &pl->head);
58bb3b37 SW	70	pl->mapped_tail = kmap(page);
	71	return 0;
	72	}
	73
68b4476b	74	int ceph_pagelist_append(struct ceph_pagelist pl, const void buf, size_t len)
58bb3b37 SW	75	{
	76	while (pl->room < len) {
	77	size_t bit = pl->room;
	78	int ret;
	79
09cbfeaf	80	memcpy(pl->mapped_tail + (pl->length & ~PAGE_MASK),
58bb3b37 SW	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
09cbfeaf	91	memcpy(pl->mapped_tail + (pl->length & ~PAGE_MASK), buf, len);
58bb3b37 SW	92	pl->length += len;
	93	pl->room -= len;
	94	return 0;
	95	}
3d14c5d2	96	EXPORT_SYMBOL(ceph_pagelist_append);
ac0b74d8	97
ae86b9e3	98	/* Allocate enough pages for a pagelist to append the given amount
ac0b74d8 GF	99	* of data without without allocating.
	100	* Returns: 0 on success, -ENOMEM on error.
	101	*/
	102	int 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	}
	118	EXPORT_SYMBOL(ceph_pagelist_reserve);
	119
ae86b9e3	120	/* Free any pages that have been preallocated. */
ac0b74d8 GF	121	int 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	}
	133	EXPORT_SYMBOL(ceph_pagelist_free_reserve);
	134
ae86b9e3	135	/* Create a truncation point. */
ac0b74d8 GF	136	void 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	}
	143	EXPORT_SYMBOL(ceph_pagelist_set_cursor);
	144
ae86b9e3	145	/* Truncate a pagelist to the given point. Move extra pages to reserve.
ac0b74d8 GF	146	* This won't sleep.
	147	* Returns: 0 on success,
	148	* -EINVAL if the pagelist doesn't match the trunc point pagelist
	149	*/
	150	int 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);
cc4829e5 WY	160	/* move from pagelist to reserve */
cc4829e5 WY	161	list_move_tail(&page->lru, &pl->free_list);
ac0b74d8 GF	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	}
	171	EXPORT_SYMBOL(ceph_pagelist_truncate);