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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>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-09-02 20:46:15 +01:00 committed by Andrew Morton
parent 0d698e2572
commit c9edc24281
2 changed files with 29 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
mm/swap.h
View File

@ -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)

32
mm/swap_state.c
View File

@ -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));
}
/**