Hi,
在 2022/09/15 0:16, Logan Gunthorpe 写道:
On 2022-09-13 19:49, Yu Kuai wrote:
From: Yu Kuai <yukuai3@xxxxxxxxxx>
Currently the nasty condition is wait_barrier() is hard to read. This
patch factor out the condition into a function.
There are no functional changes.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/raid10.c | 56 ++++++++++++++++++++++++++-------------------
1 file changed, 32 insertions(+), 24 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 64d6e4cd8a3a..56458a53043d 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -957,44 +957,52 @@ static void lower_barrier(struct r10conf *conf)
wake_up(&conf->wait_barrier);
}
+static bool stop_waiting_barrier(struct r10conf *conf)
+{
+ /* barrier is dropped */
+ if (!conf->barrier)
+ return true;
+
+ /*
+ * If there are already pending requests (preventing the barrier from
+ * rising completely), and the pre-process bio queue isn't empty, then
+ * don't wait, as we need to empty that queue to get the nr_pending
+ * count down.
+ */
+ if (atomic_read(&conf->nr_pending)) {
+ struct bio_list *bio_list = current->bio_list;
I'd probably just put the bio_list declaration at the top of this
function, then the nested if statements are not necessary. The compiler
should be able to optimize the access just fine.
if (conf->barrier) {
- struct bio_list *bio_list = current->bio_list;
- conf->nr_waiting++;
- /* Wait for the barrier to drop.
- * However if there are already pending
- * requests (preventing the barrier from
- * rising completely), and the
- * pre-process bio queue isn't empty,
- * then don't wait, as we need to empty
- * that queue to get the nr_pending
- * count down.
- */
/* Return false when nowait flag is set */
if (nowait) {
ret = false;
} else {
+ conf->nr_waiting++;
Technically speaking, I think moving nr_waiting counts as a functional
change. As best as I can see it is correct, but it should probably be at
least mentioned in the commit message, or maybe done as a separate
commit with it's own justification. That way if it causes problems down
the road, a bisect will make the issue clearer.
Thanks for your advice, I just think increase and decrease nr_waiting in
the case 'nowait' is pointless, and I move it incidentally.
I'll post a separate clean up patch to do that.
Paul, can I still add your Acked-by for this patch?
Thanks,
Kuai
Thanks,
Logan
.
