diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/zswap.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index 2d48fd59cc7a..708b82dbe8a4 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1002,6 +1002,22 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) goto fail; case ZSWAP_SWAPCACHE_NEW: /* page is locked */ + /* + * Having a local reference to the zswap entry doesn't exclude + * swapping from invalidating and recycling the swap slot. Once + * the swapcache is secured against concurrent swapping to and + * from the slot, recheck that the entry is still current before + * writing. + */ + spin_lock(&tree->lock); + if (zswap_rb_search(&tree->rbroot, entry->offset) != entry) { + spin_unlock(&tree->lock); + delete_from_swap_cache(page_folio(page)); + ret = -ENOMEM; + goto fail; + } + spin_unlock(&tree->lock); + /* decompress */ acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); dlen = PAGE_SIZE; |