ceph: add pagelist_reserve, pagelist_truncate, pagelist_set_cursor (ac0b74d8) · Commits · e / devices / android_kernel_teracube_2e

include/linux/ceph/pagelist.h

+21 −0

Original line number	Original line	Diff line number	Diff line
	@@ -8,6 +8,14 @@ struct ceph_pagelist {
	void *mapped_tail;		void *mapped_tail;
	size_t length;		size_t length;
	size_t room;		size_t room;
			struct list_head free_list;
			size_t num_pages_free;
			};

			struct ceph_pagelist_cursor {
			struct ceph_pagelist pl; / pagelist, for error checking */
			struct list_head page_lru; / page in list */
			size_t room; /* room remaining to reset to */
	};		};

	static inline void ceph_pagelist_init(struct ceph_pagelist *pl)		static inline void ceph_pagelist_init(struct ceph_pagelist *pl)
	@@ -16,11 +24,24 @@ static inline void ceph_pagelist_init(struct ceph_pagelist *pl)
	pl->mapped_tail = NULL;		pl->mapped_tail = NULL;
	pl->length = 0;		pl->length = 0;
	pl->room = 0;		pl->room = 0;
			INIT_LIST_HEAD(&pl->free_list);
			pl->num_pages_free = 0;
	}		}

	extern int ceph_pagelist_release(struct ceph_pagelist *pl);		extern int ceph_pagelist_release(struct ceph_pagelist *pl);

	extern int ceph_pagelist_append(struct ceph_pagelist pl, const void d, size_t l);		extern int ceph_pagelist_append(struct ceph_pagelist pl, const void d, size_t l);

			extern int ceph_pagelist_reserve(struct ceph_pagelist *pl, size_t space);

			extern int ceph_pagelist_free_reserve(struct ceph_pagelist *pl);

			extern void ceph_pagelist_set_cursor(struct ceph_pagelist *pl,
			struct ceph_pagelist_cursor *c);

			extern int ceph_pagelist_truncate(struct ceph_pagelist *pl,
			struct ceph_pagelist_cursor *c);

	static inline int ceph_pagelist_encode_64(struct ceph_pagelist *pl, u64 v)		static inline int ceph_pagelist_encode_64(struct ceph_pagelist *pl, u64 v)
	{		{
	__le64 ev = cpu_to_le64(v);		__le64 ev = cpu_to_le64(v);

net/ceph/pagelist.c

+97 −9

Original line number	Original line	Diff line number	Diff line
	@@ -7,35 +7,42 @@

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

	int ceph_pagelist_release(struct ceph_pagelist *pl)		int ceph_pagelist_release(struct ceph_pagelist *pl)
	{		{
	if (pl->mapped_tail)
	ceph_pagelist_unmap_tail(pl);		ceph_pagelist_unmap_tail(pl);

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

	static int ceph_pagelist_addpage(struct ceph_pagelist *pl)		static int ceph_pagelist_addpage(struct ceph_pagelist *pl)
	{		{
	struct page *page = __page_cache_alloc(GFP_NOFS);		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);
			}
	if (!page)		if (!page)
	return -ENOMEM;		return -ENOMEM;
	pl->room += PAGE_SIZE;		pl->room += PAGE_SIZE;
	list_add_tail(&page->lru, &pl->head);
	if (pl->mapped_tail)
	ceph_pagelist_unmap_tail(pl);		ceph_pagelist_unmap_tail(pl);
			list_add_tail(&page->lru, &pl->head);
	pl->mapped_tail = kmap(page);		pl->mapped_tail = kmap(page);
	return 0;		return 0;
	}		}
	@@ -63,3 +70,84 @@ int ceph_pagelist_append(struct ceph_pagelist pl, const void buf, size_t len)
	return 0;		return 0;
	}		}
	EXPORT_SYMBOL(ceph_pagelist_append);		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);
			list_del(&page->lru); /* remove from pagelist */
			list_add_tail(&page->lru, &pl->free_list); /* add to reserve */
			++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);