On Tue, 27 Aug 2013 17:50:41 +0800 Shaohua Li <shli@xxxxxxxxxx> wrote:
> -static struct stripe_head *__get_priority_stripe(struct r5conf *conf)
> +static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
> {
> - struct stripe_head *sh;
> + struct stripe_head *sh = NULL, *tmp;
> + struct list_head *handle_list = NULL;
> +
> + if (conf->worker_cnt_per_group == 0) {
> + handle_list = &conf->handle_list;
> + if (list_empty(handle_list))
> + handle_list = NULL;
> + } else if (group != ANY_GROUP) {
> + handle_list = &conf->worker_groups[group].handle_list;
> + if (list_empty(handle_list))
> + handle_list = NULL;
> + } else {
> + int i;
> + for (i = 0; i < conf->group_cnt; i++) {
> + handle_list = &conf->worker_groups[i].handle_list;
> + if (!list_empty(handle_list))
> + break;
> + }
> + if (i == conf->group_cnt)
> + handle_list = NULL;
> + }
Sorry, I meant to mention this last time...
The setting of handle_list to NULL seems unnecessary. It is sufficient to
test if it is empty.
The only interesting case is the last 'else' above. That is only reached if
worker_cnt_per_group != 0 so handle_list will get set to some list_head.
If all list_heads are empty, handle_list will be set to the last list_head
so a list_empty(handle_list) test is perfectly safe.
Also with the current code:
>
> pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
> __func__,
> - list_empty(&conf->handle_list) ? "empty" : "busy",
> + list_empty(handle_list) ? "empty" : "busy",
^^^^^^^^^^^^^^^^^^^^^^^
This will crash.
Could you fix that up please?
Thanks.
NeilBrown
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