From: "Matthew Wilcox (Oracle)" willy@infradead.org
mainline inclusion from mainline-v6.7-rc1 commit b0b598ee08f9759b70971e297cf7ddd3eaaa5245 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I93R23 CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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The original problem of the overly long list of waiters on a locked page was solved properly by commit 9a1ea439b16b ("mm: put_and_wait_on_page_locked() while page is migrated"). In the meantime, using bookmarks for the writeback bit can cause livelocks, so we need to stop using them.
Link: https://lkml.kernel.org/r/20231010035829.544242-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org Cc: Bin Lai sclaibin@gmail.com Cc: Benjamin Segall bsegall@google.com Cc: Daniel Bristot de Oliveira bristot@redhat.com Cc: Dietmar Eggemann dietmar.eggemann@arm.com Cc: Ingo Molnar mingo@redhat.com Cc: Juri Lelli juri.lelli@redhat.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Mel Gorman mgorman@suse.de Cc: Peter Zijlstra peterz@infradead.org Cc: Steven Rostedt (Google) rostedt@goodmis.org Cc: Valentin Schneider vschneid@redhat.com Cc: Vincent Guittot vincent.guittot@linaro.org
Cc: Ingo Molnar mingo@kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Zizhi Wo wozizhi@huawei.com --- mm/filemap.c | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c index 3a23350e7125..da44ba00526f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1142,32 +1142,13 @@ static void folio_wake_bit(struct folio *folio, int bit_nr) wait_queue_head_t *q = folio_waitqueue(folio); struct wait_page_key key; unsigned long flags; - wait_queue_entry_t bookmark;
key.folio = folio; key.bit_nr = bit_nr; key.page_match = 0;
- bookmark.flags = 0; - bookmark.private = NULL; - bookmark.func = NULL; - INIT_LIST_HEAD(&bookmark.entry); - spin_lock_irqsave(&q->lock, flags); - __wake_up_locked_key_bookmark(q, TASK_NORMAL, &key, &bookmark); - - while (bookmark.flags & WQ_FLAG_BOOKMARK) { - /* - * Take a breather from holding the lock, - * allow pages that finish wake up asynchronously - * to acquire the lock and remove themselves - * from wait queue - */ - spin_unlock_irqrestore(&q->lock, flags); - cpu_relax(); - spin_lock_irqsave(&q->lock, flags); - __wake_up_locked_key_bookmark(q, TASK_NORMAL, &key, &bookmark); - } + __wake_up_locked_key(q, TASK_NORMAL, &key);
/* * It's possible to miss clearing waiters here, when we woke our page