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Message-Id: <20210712061048.979749149@linuxfoundation.org>
Date: Mon, 12 Jul 2021 08:13:15 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Miaohe Lin <linmiaohe@...wei.com>,
Colin Ian King <colin.king@...onical.com>,
Dan Streetman <ddstreet@...e.org>,
Nathan Chancellor <nathan@...nel.org>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Seth Jennings <sjenning@...hat.com>,
Tian Tao <tiantao6@...ilicon.com>,
Vitaly Wool <vitaly.wool@...sulko.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.13 772/800] mm/zswap.c: fix two bugs in zswap_writeback_entry()
From: Miaohe Lin <linmiaohe@...wei.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@...wei.com>
Cc: Colin Ian King <colin.king@...onical.com>
Cc: Dan Streetman <ddstreet@...e.org>
Cc: Nathan Chancellor <nathan@...nel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: Seth Jennings <sjenning@...hat.com>
Cc: Tian Tao <tiantao6@...ilicon.com>
Cc: Vitaly Wool <vitaly.wool@...sulko.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.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);
--
2.30.2
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