From: Miaohe Lin linmiaohe@huawei.com
[ Upstream commit 46b76f2e09dc35f70aca2f4349eb0d158f53fe93 ]
In the ZSWAP_SWAPCACHE_FAIL and ZSWAP_SWAPCACHE_EXIST case, we forgot to call zpool_unmap_handle() when zpool can't sleep. And we might sleep in zswap_get_swap_cache_page() while zpool can't sleep. To fix all of these, zpool_unmap_handle() should be done before zswap_get_swap_cache_page() when zpool can't sleep.
Link: https://lkml.kernel.org/r/20210522092242.3233191-4-linmiaohe@huawei.com Fixes: fc6697a89f56 ("mm/zswap: add the flag can_sleep_mapped") Signed-off-by: Miaohe Lin linmiaohe@huawei.com Cc: Colin Ian King colin.king@canonical.com Cc: Dan Streetman ddstreet@ieee.org Cc: Nathan Chancellor nathan@kernel.org Cc: Sebastian Andrzej Siewior bigeasy@linutronix.de Cc: Seth Jennings sjenning@redhat.com Cc: Tian Tao tiantao6@hisilicon.com Cc: Vitaly Wool vitaly.wool@konsulko.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/zswap.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/mm/zswap.c b/mm/zswap.c index 20763267a219..706e0f98125a 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -967,6 +967,13 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) spin_unlock(&tree->lock); BUG_ON(offset != entry->offset);
+ src = (u8 *)zhdr + sizeof(struct zswap_header); + if (!zpool_can_sleep_mapped(pool)) { + memcpy(tmp, src, entry->length); + src = tmp; + zpool_unmap_handle(pool, handle); + } + /* try to allocate swap cache page */ switch (zswap_get_swap_cache_page(swpentry, &page)) { case ZSWAP_SWAPCACHE_FAIL: /* no memory or invalidate happened */ @@ -982,17 +989,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) case ZSWAP_SWAPCACHE_NEW: /* page is locked */ /* decompress */ acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); - dlen = PAGE_SIZE; - src = (u8 *)zhdr + sizeof(struct zswap_header); - - if (!zpool_can_sleep_mapped(pool)) { - - memcpy(tmp, src, entry->length); - src = tmp; - - zpool_unmap_handle(pool, handle); - }
mutex_lock(acomp_ctx->mutex); sg_init_one(&input, src, entry->length);