From 3b42c741b1bf52ee9ed6fba5f9636d80ddacf73f Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Sat, 20 Feb 2021 17:38:43 +0800 Subject: [PATCH] f2fs: update comments for explicit memory barrier Add more detailed comments for explicit memory barrier used by f2fs, in order to enhance code readability. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/checkpoint.c | 6 +++++- fs/f2fs/segment.c | 6 +++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index d0e5ef7e232e3..f6169611270f7 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -1818,7 +1818,11 @@ int f2fs_issue_checkpoint(struct f2fs_sb_info *sbi) llist_add(&req.llnode, &cprc->issue_list); atomic_inc(&cprc->queued_ckpt); - /* update issue_list before we wake up issue_checkpoint thread */ + /* + * update issue_list before we wake up issue_checkpoint thread, + * this smp_mb() pairs with another barrier in ___wait_event(), + * see more details in comments of waitqueue_active(). + */ smp_mb(); if (waitqueue_active(&cprc->ckpt_wait_queue)) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index b8c20d29431da..29403540ff6ed 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -653,7 +653,11 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi, nid_t ino) llist_add(&cmd.llnode, &fcc->issue_list); - /* update issue_list before we wake up issue_flush thread */ + /* + * update issue_list before we wake up issue_flush thread, this + * smp_mb() pairs with another barrier in ___wait_event(), see + * more details in comments of waitqueue_active(). + */ smp_mb(); if (waitqueue_active(&fcc->flush_wait_queue)) -- 2.30.2