14  * balloon_page_alloc - allocates a new page for insertion into the balloon
15  *			  page list.
17  * Driver must call it to properly allocate a new enlisted balloon page.
19  * the guest system.  This function returns the page address for the recently
20  * allocated page or NULL in the case we fail to allocate a new page this turn.
22 struct page *balloon_page_alloc(void)  in balloon_page_alloc()
24 	struct page *page = alloc_page(balloon_mapping_gfp_mask() |  in balloon_page_alloc()  local
26 	return page;  in balloon_page_alloc()
31  * balloon_page_enqueue - allocates a new page and inserts it into the balloon
32  *			  page list.
33  * @b_dev_info: balloon device descriptor where we will insert a new page to
34  * @page: new page to enqueue - allocated using balloon_page_alloc.
36  * Driver must call it to properly enqueue a new allocated balloon page
38  * This function returns the page address for the recently enqueued page or
39  * NULL in the case we fail to allocate a new page this turn.
42 			  struct page *page)  in balloon_page_enqueue()  argument
47 	 * Block others from accessing the 'page' when we get around to  in balloon_page_enqueue()
49 	 * holding a reference to the 'page' at this point.  in balloon_page_enqueue()
51 	BUG_ON(!trylock_page(page));  in balloon_page_enqueue()
53 	balloon_page_insert(b_dev_info, page);  in balloon_page_enqueue()
56 	unlock_page(page);  in balloon_page_enqueue()
61  * balloon_page_dequeue - removes a page from balloon's page list and returns
62  *			  the its address to allow the driver release the page.
63  * @b_dev_info: balloon device decriptor where we will grab a page from.
65  * Driver must call it to properly de-allocate a previous enlisted balloon page
67  * This function returns the page address for the recently dequeued page or
68  * NULL in the case we find balloon's page list temporarily empty due to
71 struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)  in balloon_page_dequeue()
73 	struct page *page, *tmp;  in balloon_page_dequeue()  local
79 	list_for_each_entry_safe(page, tmp, &b_dev_info->pages, lru) {  in balloon_page_dequeue()
81 		 * Block others from accessing the 'page' while we get around  in balloon_page_dequeue()
82 		 * establishing additional references and preparing the 'page'  in balloon_page_dequeue()
85 		if (trylock_page(page)) {  in balloon_page_dequeue()
87 			if (PageIsolated(page)) {  in balloon_page_dequeue()
89 				unlock_page(page);  in balloon_page_dequeue()
93 			balloon_page_delete(page);  in balloon_page_dequeue()
95 			unlock_page(page);  in balloon_page_dequeue()
104 		 * If we are unable to dequeue a balloon page because the page  in balloon_page_dequeue()
115 		page = NULL;  in balloon_page_dequeue()
117 	return page;  in balloon_page_dequeue()
123 bool balloon_page_isolate(struct page *page, isolate_mode_t mode)  in balloon_page_isolate()  argument
126 	struct balloon_dev_info *b_dev_info = balloon_page_device(page);  in balloon_page_isolate()
130 	list_del(&page->lru);  in balloon_page_isolate()
137 void balloon_page_putback(struct page *page)  in balloon_page_putback()  argument
139 	struct balloon_dev_info *b_dev_info = balloon_page_device(page);  in balloon_page_putback()
143 	list_add(&page->lru, &b_dev_info->pages);  in balloon_page_putback()
149 /* move_to_new_page() counterpart for a ballooned page */
151 		struct page *newpage, struct page *page,  in balloon_page_migrate()  argument
154 	struct balloon_dev_info *balloon = balloon_page_device(page);  in balloon_page_migrate()
164 	VM_BUG_ON_PAGE(!PageLocked(page), page);  in balloon_page_migrate()
167 	return balloon->migratepage(balloon, newpage, page, mode);  in balloon_page_migrate()