The patch titled
Subject: mm/zswap.c: fix two bugs in zswap_writeback_entry()
has been added to the -mm tree. Its filename is
mm-zswapc-fix-two-bugs-in-zswap_writeback_entry.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-zswapc-fix-two-bugs-in-zswap_writeback_entry.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-zswapc-fix-two-bugs-in-zswap_writeback_entry.patch
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/zswap.c: fix two bugs in zswap_writeback_entry()
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@xxxxxxxxxx
Fixes: fc6697a89f56 ("mm/zswap: add the flag can_sleep_mapped")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Tian Tao <tiantao6@xxxxxxxxxxxxx>
Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zswap.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
--- a/mm/zswap.c~mm-zswapc-fix-two-bugs-in-zswap_writeback_entry
+++ a/mm/zswap.c
@@ -967,6 +967,13 @@ static int zswap_writeback_entry(struct
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
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);
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-swapfile-use-percpu_ref-to-serialize-against-concurrent-swapoff.patch
swap-fix-do_swap_page-race-with-swapoff.patch
mm-swap-remove-confusing-checking-for-non_swap_entry-in-swap_ra_info.patch
mm-shmem-fix-shmem_swapin-race-with-swapoff.patch
mm-swapfile-move-get_swap_page_of_type-under-config_hibernation.patch
mm-swap-remove-unused-local-variable-nr_shadows.patch
mm-swap_slotsc-delete-meaningless-forward-declarations.patch
mm-swap-remove-unused-global-variable-nr_swapper_spaces.patch
mm-huge_memoryc-remove-dedicated-macro-hpage_cache_index_mask.patch
mm-huge_memoryc-use-page-deferred_list.patch
mm-huge_memoryc-add-missing-read-only-thp-checking-in-transparent_hugepage_enabled.patch
mm-huge_memoryc-add-missing-read-only-thp-checking-in-transparent_hugepage_enabled-v4.patch
mm-huge_memoryc-remove-unnecessary-tlb_remove_page_size-for-huge-zero-pmd.patch
mm-huge_memoryc-dont-discard-hugepage-if-other-processes-are-mapping-it.patch
mm-zswapc-remove-unused-function-zswap_debugfs_exit.patch
mm-zswapc-avoid-unnecessary-copy-in-at-map-time.patch
mm-zswapc-fix-two-bugs-in-zswap_writeback_entry.patch
