On 9/14/23 17:45, Kemeng Shi wrote:
Commit 670d21c6e17f6 ("fuse: remove reliance on bdi congestion") change how
congestion_threshold is used and lock in
fuse_conn_congestion_threshold_write is not needed anymore.
1. Access to supe_block is removed along with removing of bdi congestion.
Then down_read(&fc->killsb) which protecting access to super_block is no
needed.
2. Compare num_background and congestion_threshold without holding
bg_lock. Then there is no need to hold bg_lock to update
congestion_threshold.
Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
---
fs/fuse/control.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/fs/fuse/control.c b/fs/fuse/control.c
index 247ef4f76761..c5d7bf80efed 100644
--- a/fs/fuse/control.c
+++ b/fs/fuse/control.c
@@ -174,11 +174,7 @@ static ssize_t fuse_conn_congestion_threshold_write(struct file *file,
if (!fc)
goto out;
- down_read(&fc->killsb);
- spin_lock(&fc->bg_lock);
fc->congestion_threshold = val;
- spin_unlock(&fc->bg_lock);
- up_read(&fc->killsb);
fuse_conn_put(fc);
out:
return ret;
Yeah, I don't see readers holding any of these locks.
I just wonder if it wouldn't be better to use WRITE_ONCE to ensure a
single atomic operation to store the value.
Thanks,
Bernd
