Commit c9edc242 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

swap: add swap_cache_get_folio() 

Convert lookup_swap_cache() into swap_cache_get_folio() and add a
lookup_swap_cache() wrapper around it.

[akpm@linux-foundation.org: add CONFIG_SWAP=n stub for swap_cache_get_folio()]
Link: https://lkml.kernel.org/r/20220902194653.1739778-20-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0d698e25

mm/swap.h

+8 −0
Original line number Diff line number Diff line
@@ -39,6 +39,8 @@ void __delete_from_swap_cache(struct folio *folio, 
void delete_from_swap_cache(struct folio *folio);

void clear_shadow_from_swap_cache(int type, unsigned long begin,

				  unsigned long end);

struct folio *swap_cache_get_folio(swp_entry_t entry,

		struct vm_area_struct *vma, unsigned long addr);

struct page *lookup_swap_cache(swp_entry_t entry,

			       struct vm_area_struct *vma,

			       unsigned long addr);
@@ -99,6 +101,12 @@ static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 
	return 0;

}



static inline struct folio *swap_cache_get_folio(swp_entry_t entry,

		struct vm_area_struct *vma, unsigned long addr)

{

	return NULL;

}



static inline struct page *lookup_swap_cache(swp_entry_t swp,

					     struct vm_area_struct *vma,

					     unsigned long addr)

mm/swap_state.c

+21 −11
Original line number Diff line number Diff line
@@ -317,24 +317,24 @@ static inline bool swap_use_vma_readahead(void) 
}



/*

 * Lookup a swap entry in the swap cache. A found page will be returned

 * Lookup a swap entry in the swap cache. A found folio will be returned

 * unlocked and with its refcount incremented - we rely on the kernel

 * lock getting page table operations atomic even if we drop the page

 * lock getting page table operations atomic even if we drop the folio

 * lock before returning.

 */

struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma,

			       unsigned long addr)

struct folio *swap_cache_get_folio(swp_entry_t entry,

		struct vm_area_struct *vma, unsigned long addr)

{

	struct page *page;

	struct folio *folio;

	struct swap_info_struct *si;



	si = get_swap_device(entry);

	if (!si)

		return NULL;

	page = find_get_page(swap_address_space(entry), swp_offset(entry));

	folio = filemap_get_folio(swap_address_space(entry), swp_offset(entry));

	put_swap_device(si);



	if (page) {

	if (folio) {

		bool vma_ra = swap_use_vma_readahead();

		bool readahead;
@@ -342,10 +342,10 @@ struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma, 
		 * At the moment, we don't support PG_readahead for anon THP

		 * so let's bail out rather than confusing the readahead stat.

		 */

		if (unlikely(PageTransCompound(page)))

			return page;

		if (unlikely(folio_test_large(folio)))

			return folio;



		readahead = TestClearPageReadahead(page);

		readahead = folio_test_clear_readahead(folio);

		if (vma && vma_ra) {

			unsigned long ra_val;

			int win, hits;
@@ -366,7 +366,17 @@ struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma, 
		}

	}



	return page;

	return folio;

}



struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma,

			       unsigned long addr)

{

	struct folio *folio = swap_cache_get_folio(entry, vma, addr);



	if (!folio)

		return NULL;

	return folio_file_page(folio, swp_offset(entry));

}



/**