{
struct swap_info_struct *si;
struct folio *folio;
+ struct page *page;
void *shadow = NULL;
*new_page_allocated = false;
+ si = get_swap_device(entry);
+ if (!si)
+ return NULL;
for (;;) {
int err;
* called after swap_cache_get_folio() failed, re-calling
* that would confuse statistics.
*/
- si = get_swap_device(entry);
- if (!si)
- return NULL;
folio = filemap_get_folio(swap_address_space(entry),
swp_offset(entry));
- put_swap_device(si);
- if (!IS_ERR(folio))
- return folio_file_page(folio, swp_offset(entry));
+ if (!IS_ERR(folio)) {
+ page = folio_file_page(folio, swp_offset(entry));
+ goto got_page;
+ }
/*
* Just skip read ahead for unused swap slot.
* else swap_off will be aborted if we return NULL.
*/
if (!__swp_swapcount(entry) && swap_slot_cache_enabled)
- return NULL;
+ goto fail_put_swap;
/*
* Get a new page to read into from swap. Allocate it now,
*/
folio = vma_alloc_folio(gfp_mask, 0, vma, addr, false);
if (!folio)
- return NULL;
+ goto fail_put_swap;
/*
* Swap entry may have been freed since our caller observed it.
folio_put(folio);
if (err != -EEXIST)
- return NULL;
+ goto fail_put_swap;
/*
* We might race against __delete_from_swap_cache(), and
/* Caller will initiate read into locked folio */
folio_add_lru(folio);
*new_page_allocated = true;
- return &folio->page;
+ page = &folio->page;
+got_page:
+ put_swap_device(si);
+ return page;
fail_unlock:
put_swap_folio(folio, entry);
folio_unlock(folio);
folio_put(folio);
+fail_put_swap:
+ put_swap_device(si);
return NULL;
}
* and reading the disk if it is not already cached.
* A failure return means that either the page allocation failed or that
* the swap entry is no longer in use.
+ *
+ * get/put_swap_device() aren't needed to call this function, because
+ * __read_swap_cache_async() call them and swap_readpage() holds the
+ * swap cache folio lock.
*/
struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma,