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: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/mm/swap_state.c b/mm/swap_state.c
index a7e0438..b96bf4e 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -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));
}
/**
