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SubjectRe: [PATCH v3 1/5] md/raid10: factor out code from wait_barrier() to stop_waiting_barrier()
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On 9/16/22 7:34 PM, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@huawei.com>
>
> Currently the nasty condition in wait_barrier() is hard to read. This
> patch factors out the condition into a function.
>
> There are no functional changes.
>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> Acked-by: Paul Menzel <pmenzel@molgen.mpg.de>
> ---
> drivers/md/raid10.c | 50 +++++++++++++++++++++++++--------------------
> 1 file changed, 28 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 64d6e4cd8a3a..37fd9284054e 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -957,41 +957,47 @@ static void lower_barrier(struct r10conf *conf)
> wake_up(&conf->wait_barrier);
> }
>
> +static bool stop_waiting_barrier(struct r10conf *conf)
> +{
> + struct bio_list *bio_list = current->bio_list;
> +
> + /* 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) && bio_list &&
> + (!bio_list_empty(&bio_list[0]) || !bio_list_empty(&bio_list[1])))
> + return true;
> +
> + /* move on if recovery thread is blocked by us */
> + if (conf->mddev->thread->tsk == current &&
> + test_bit(MD_RECOVERY_RUNNING, &conf->mddev->recovery) &&
> + conf->nr_queued > 0)
> + return true;
> +
> + return false;
> +}
> +
> static bool wait_barrier(struct r10conf *conf, bool nowait)
> {
> bool ret = true;
>
> spin_lock_irq(&conf->resync_lock);
> 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 {
> raid10_log(conf->mddev, "wait barrier");
> wait_event_lock_irq(conf->wait_barrier,
> - !conf->barrier ||
> - (atomic_read(&conf->nr_pending) &&
> - bio_list &&
> - (!bio_list_empty(&bio_list[0]) ||
> - !bio_list_empty(&bio_list[1]))) ||
> - /* move on if recovery thread is
> - * blocked by us
> - */
> - (conf->mddev->thread->tsk == current &&
> - test_bit(MD_RECOVERY_RUNNING,
> - &conf->mddev->recovery) &&
> - conf->nr_queued > 0),
> + stop_waiting_barrier(conf),
> conf->resync_lock);
> }
> conf->nr_waiting--;

Acked-by: Guoqing Jiang <guoqing.jiang@linux.dev>

Thanks,
Guoqing

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