On Thu, Apr 27, 2017 at 08:54:35AM -0700, Bart Van Assche wrote:
> When verifying whether or not a blk-mq driver forgot to kick the
> requeue list after having requeued a request it is important to
> be able to verify the contents of the requeue list. Hence export
> that list through debugfs.
Reviewed-by: Omar Sandoval <osandov@xxxxxx>
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Cc: Omar Sandoval <osandov@xxxxxx>
> Cc: Hannes Reinecke <hare@xxxxxxxx>
> ---
> block/blk-mq-debugfs.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
> index 9cb673bc7230..5092d90e37f6 100644
> --- a/block/blk-mq-debugfs.c
> +++ b/block/blk-mq-debugfs.c
> @@ -341,6 +341,50 @@ static int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
> return 0;
> }
>
> +static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
> + __acquires(&q->requeue_lock)
> +{
> + struct request_queue *q = m->private;
> +
> + spin_lock(&q->requeue_lock);
> + return seq_list_start(&q->requeue_list, *pos);
> +}
> +
> +static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
> +{
> + struct request_queue *q = m->private;
> +
> + return seq_list_next(v, &q->requeue_list, pos);
> +}
> +
> +static void queue_requeue_list_stop(struct seq_file *m, void *v)
> + __releases(&q->requeue_lock)
> +{
> + struct request_queue *q = m->private;
> +
> + spin_unlock(&q->requeue_lock);
> +}
> +
> +static const struct seq_operations queue_requeue_list_seq_ops = {
> + .start = queue_requeue_list_start,
> + .next = queue_requeue_list_next,
> + .stop = queue_requeue_list_stop,
> + .show = blk_mq_debugfs_rq_show,
> +};
> +
> +static int queue_requeue_list_open(struct inode *inode, struct file *file)
> +{
> + return blk_mq_debugfs_seq_open(inode, file,
> + &queue_requeue_list_seq_ops);
> +}
> +
> +static const struct file_operations queue_requeue_list_fops = {
> + .open = queue_requeue_list_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = seq_release,
> +};
> +
> static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
> __acquires(&hctx->lock)
> {
> @@ -831,6 +875,7 @@ static const struct file_operations ctx_completed_fops = {
> };
>
> static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
> + {"requeue_list", 0400, &queue_requeue_list_fops},
> {"poll_stat", 0400, &queue_poll_stat_fops},
> {"state", 0600, &blk_queue_flags_fops},
> {},
> --
> 2.12.2
>
