Commit ee32f323 authored by Juergen Gross's avatar Juergen Gross
Browse files

xen: don't use page->lru for ZONE_DEVICE memory 



Commit 9e2369c0 ("xen: add helpers to allocate unpopulated
memory") introduced usage of ZONE_DEVICE memory for foreign memory
mappings.

Unfortunately this collides with using page->lru for Xen backend
private page caches.

Fix that by using page->zone_device_data instead.

Cc: <stable@vger.kernel.org> # 5.9
Fixes: 9e2369c0 ("xen: add helpers to allocate unpopulated memory")
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovksy@oracle.com>
Reviewed-by: default avatarJason Andryuk <jandryuk@gmail.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent ca33479c

drivers/xen/grant-table.c

+58 −7
Original line number Diff line number Diff line
@@ -813,10 +813,63 @@ int gnttab_alloc_pages(int nr_pages, struct page **pages) 
}

EXPORT_SYMBOL_GPL(gnttab_alloc_pages);



#ifdef CONFIG_XEN_UNPOPULATED_ALLOC

static inline void cache_init(struct gnttab_page_cache *cache)

{

	cache->pages = NULL;

}



static inline bool cache_empty(struct gnttab_page_cache *cache)

{

	return !cache->pages;

}



static inline struct page *cache_deq(struct gnttab_page_cache *cache)

{

	struct page *page;



	page = cache->pages;

	cache->pages = page->zone_device_data;



	return page;

}



static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)

{

	page->zone_device_data = cache->pages;

	cache->pages = page;

}

#else

static inline void cache_init(struct gnttab_page_cache *cache)

{

	INIT_LIST_HEAD(&cache->pages);

}



static inline bool cache_empty(struct gnttab_page_cache *cache)

{

	return list_empty(&cache->pages);

}



static inline struct page *cache_deq(struct gnttab_page_cache *cache)

{

	struct page *page;



	page = list_first_entry(&cache->pages, struct page, lru);

	list_del(&page->lru);



	return page;

}



static inline void cache_enq(struct gnttab_page_cache *cache, struct page *page)

{

	list_add(&page->lru, &cache->pages);

}

#endif



void gnttab_page_cache_init(struct gnttab_page_cache *cache)

{

	spin_lock_init(&cache->lock);

	INIT_LIST_HEAD(&cache->pages);

	cache_init(cache);

	cache->num_pages = 0;

}

EXPORT_SYMBOL_GPL(gnttab_page_cache_init);
@@ -827,13 +880,12 @@ int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page) 


	spin_lock_irqsave(&cache->lock, flags);



	if (list_empty(&cache->pages)) {

	if (cache_empty(cache)) {

		spin_unlock_irqrestore(&cache->lock, flags);

		return gnttab_alloc_pages(1, page);

	}



	page[0] = list_first_entry(&cache->pages, struct page, lru);

	list_del(&page[0]->lru);

	page[0] = cache_deq(cache);

	cache->num_pages--;



	spin_unlock_irqrestore(&cache->lock, flags);
@@ -851,7 +903,7 @@ void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page, 
	spin_lock_irqsave(&cache->lock, flags);



	for (i = 0; i < num; i++)

		list_add(&page[i]->lru, &cache->pages);

		cache_enq(cache, page[i]);

	cache->num_pages += num;



	spin_unlock_irqrestore(&cache->lock, flags);
@@ -867,8 +919,7 @@ void gnttab_page_cache_shrink(struct gnttab_page_cache *cache, unsigned int num) 
	spin_lock_irqsave(&cache->lock, flags);



	while (cache->num_pages > num) {

		page[i] = list_first_entry(&cache->pages, struct page, lru);

		list_del(&page[i]->lru);

		page[i] = cache_deq(cache);

		cache->num_pages--;

		if (++i == ARRAY_SIZE(page)) {

			spin_unlock_irqrestore(&cache->lock, flags);

drivers/xen/unpopulated-alloc.c

+11 −9
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ 
#include <xen/xen.h>



static DEFINE_MUTEX(list_lock);

static LIST_HEAD(page_list);

static struct page *page_list;

static unsigned int list_count;



static int fill_list(unsigned int nr_pages)
@@ -84,7 +84,8 @@ static int fill_list(unsigned int nr_pages) 
		struct page *pg = virt_to_page(vaddr + PAGE_SIZE * i);



		BUG_ON(!virt_addr_valid(vaddr + PAGE_SIZE * i));

		list_add(&pg->lru, &page_list);

		pg->zone_device_data = page_list;

		page_list = pg;

		list_count++;

	}
@@ -118,12 +119,10 @@ int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) 
	}



	for (i = 0; i < nr_pages; i++) {

		struct page *pg = list_first_entry_or_null(&page_list,

							   struct page,

							   lru);

		struct page *pg = page_list;



		BUG_ON(!pg);

		list_del(&pg->lru);

		page_list = pg->zone_device_data;

		list_count--;

		pages[i] = pg;
@@ -134,7 +133,8 @@ int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages) 
				unsigned int j;



				for (j = 0; j <= i; j++) {

					list_add(&pages[j]->lru, &page_list);

					pages[j]->zone_device_data = page_list;

					page_list = pages[j];

					list_count++;

				}

				goto out;
@@ -160,7 +160,8 @@ void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages) 


	mutex_lock(&list_lock);

	for (i = 0; i < nr_pages; i++) {

		list_add(&pages[i]->lru, &page_list);

		pages[i]->zone_device_data = page_list;

		page_list = pages[i];

		list_count++;

	}

	mutex_unlock(&list_lock);
@@ -189,7 +190,8 @@ static int __init init(void) 
			struct page *pg =

				pfn_to_page(xen_extra_mem[i].start_pfn + j);



			list_add(&pg->lru, &page_list);

			pg->zone_device_data = page_list;

			page_list = pg;

			list_count++;

		}

	}

include/xen/grant_table.h

+4 −0
Original line number Diff line number Diff line
@@ -200,7 +200,11 @@ void gnttab_free_pages(int nr_pages, struct page **pages); 


struct gnttab_page_cache {

	spinlock_t		lock;

#ifdef CONFIG_XEN_UNPOPULATED_ALLOC

	struct page		*pages;

#else

	struct list_head	pages;

#endif

	unsigned int		num_pages;

};

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