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| author | Vitaly Wool <vitalywool@gmail.com> | 2017-10-03 16:15:06 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-10-03 17:54:24 -0700 |
| commit | 3552935742e0d5f0dafd823736f45bdaa7ba672c (patch) | |
| tree | 43039ba93ba9302c5ff1dc10716510d104f1d8c0 | |
| parent | 6818600ff094ca255a7fe31838ad50c29656c3c5 (diff) | |
| download | lwn-3552935742e0d5f0dafd823736f45bdaa7ba672c.tar.gz lwn-3552935742e0d5f0dafd823736f45bdaa7ba672c.zip | |
z3fold: fix stale list handling
Fix the situation when clear_bit() is called for page->private before
the page pointer is actually assigned. While at it, remove work_busy()
check because it is costly and does not give 100% guarantee anyway.
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: <Oleksiy.Avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/z3fold.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/mm/z3fold.c b/mm/z3fold.c index b04fa3ba1bf2..b2ba2ba585f3 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -250,6 +250,7 @@ static void __release_z3fold_page(struct z3fold_header *zhdr, bool locked) WARN_ON(!list_empty(&zhdr->buddy)); set_bit(PAGE_STALE, &page->private); + clear_bit(NEEDS_COMPACTING, &page->private); spin_lock(&pool->lock); if (!list_empty(&page->lru)) list_del(&page->lru); @@ -303,7 +304,6 @@ static void free_pages_work(struct work_struct *w) list_del(&zhdr->buddy); if (WARN_ON(!test_bit(PAGE_STALE, &page->private))) continue; - clear_bit(NEEDS_COMPACTING, &page->private); spin_unlock(&pool->stale_lock); cancel_work_sync(&zhdr->work); free_z3fold_page(page); @@ -624,10 +624,8 @@ lookup: * stale pages list. cancel_work_sync() can sleep so we must make * sure it won't be called in case we're in atomic context. */ - if (zhdr && (can_sleep || !work_pending(&zhdr->work) || - !unlikely(work_busy(&zhdr->work)))) { + if (zhdr && (can_sleep || !work_pending(&zhdr->work))) { list_del(&zhdr->buddy); - clear_bit(NEEDS_COMPACTING, &page->private); spin_unlock(&pool->stale_lock); if (can_sleep) cancel_work_sync(&zhdr->work); |