Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.12 673/700] mm/zswap.c: fix two bugs in zswap_writeback_entry() | Date | Mon, 12 Jul 2021 08:12:36 +0200 |
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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 578d9f256920..91f7439fde7f 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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