Commit 6f890df0 authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim

f2fs: fix out-of-order execution in f2fs_issue_flush

In f2fs_issue_flush, due to out-of-order execution of CPU, wake_up can
be called before we insert issue_list, result in long latency of
wait_for_completion. Fix this by adding smp_mb() to force the order of
related codes.
Signed-off-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 5f656541
...@@ -549,7 +549,10 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi) ...@@ -549,7 +549,10 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi)
atomic_inc(&fcc->issing_flush); atomic_inc(&fcc->issing_flush);
llist_add(&cmd.llnode, &fcc->issue_list); llist_add(&cmd.llnode, &fcc->issue_list);
if (!fcc->dispatch_list) /* update issue_list before we wake up issue_flush thread */
smp_mb();
if (waitqueue_active(&fcc->flush_wait_queue))
wake_up(&fcc->flush_wait_queue); wake_up(&fcc->flush_wait_queue);
if (fcc->f2fs_issue_flush) { if (fcc->f2fs_issue_flush) {
......
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