[Devel] [PATCH vz9 v1 05/63] dm-ploop: convert wait_list and wb_batch_llist to use lockless lists

[Pavel Tikhomirov]

On 1/24/25 23:35, Alexander Atanasov wrote:
> @@ -801,11 +799,21 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
>   
>   	WARN_ON_ONCE(!test_bit(MD_WRITEBACK, &md->status));
>   	clear_bit(MD_WRITEBACK, &md->status);
> +	/* protect piwb */
> +	write_lock_irqsave(&ploop->bat_rwlock, flags);
>   	md->piwb = NULL;
> -	list_splice_tail_init(&md->wait_list, &list);
>   	write_unlock_irqrestore(&ploop->bat_rwlock, flags);
>   	kunmap_local(dst_clu);
>   
> +	wait_llist_pending = llist_del_all(&md->wait_llist);
> +	if (wait_llist_pending) {
> +		wait_llist_pending = llist_reverse_order(wait_llist_pending);
> +		llist_for_each_safe(pos, t, wait_llist_pending) {
> +			pio = list_entry((struct list_head *)pos, typeof(*pio), list);

Please use llist_for_each_entry_safe.

> +			list_add(&pio->list, &list);
> +		}
> +	}
> +
>   	if (!list_empty(&list))
>   		ploop_dispatch_pios(ploop, NULL, &list);
>   }

Same thing in other 20 places:

turmoil at fedora:~/devel/kernel-vz/kernel-vz9-second$ git log 
rh9-5.14.0-427.44.1.vz9.80.11..rh9-5.14.0-427.44.1.vz9.80.12 -p | grep 
llist_for_each | grep -v entry | grep '^+'
+	llist_for_each_safe(pos, t, ll_ready_pios) {
+	llist_for_each_safe(pos, t,  ) {
+	llist_for_each_safe(pos, t, list) {
+		llist_for_each_safe(pos, t, llwork) {
+	llist_for_each_safe(pos, t, ll_wb_batch) {
+	llist_for_each_safe(pos, t, ploop->wb_batch_llist.first) {
+		llist_for_each_safe(pos, t, deferred_pios.first) {
+	llist_for_each_safe(pos, t, llist.first) {
+	llist_for_each_safe(pos, t, pios->first) {
+	llist_for_each_safe(pos, t, deferred_pios.first) {
+	llist_for_each_safe(pos, t, list) {
+		llist_for_each_safe(pos, t, lldeferred_pios) {
+	llist_for_each_safe(pos, t, cow_llist) {
+	llist_for_each_safe(pos, t, pios) {
+	llist_for_each_safe(pos, t, discpios) {
+	llist_for_each_safe(pos, t, llpios) {
+	llist_for_each_safe(pos, t, llflush_pios) {
+		llist_for_each_safe(pos, t, llist_reverse_order(lldeferred_pios)) {
+		llist_for_each_safe(pos, t, suspended_pending) {
+		llist_for_each_safe(pos, t, enospc_pending) {
+		llist_for_each_safe(pos, t, wait_llist_pending) {
turmoil at fedora:~/devel/kernel-vz/kernel-vz9-second$ git log 
rh9-5.14.0-427.44.1.vz9.80.11..rh9-5.14.0-427.44.1.vz9.80.12 -p | grep 
llist_for_each | grep -v entry | grep '^+' | wc -l
21

There is no point in iterating over llist and convert llist_node to 
entry manually.

-- 
Best regards, Tikhomirov Pavel
Senior Software Developer, Virtuozzo.