firewire: core: use guard macro to maintain list of asynchronous transaction

The core function maintains pending asynchronous transactions by list in
the instance of fw_card. The concurrent access to the list is protected
by spinlock in the instance.

This commit uses guard macro to maintain the spinlock.

Link: https://lore.kernel.org/r/20240805085408.251763-14-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

drivers/firewire/core-transaction.c

@@ -49,35 +49,31 @@ static int close_transaction(struct fw_transaction *transaction, struct fw_card
 			     u32 response_tstamp)
 {
 	struct fw_transaction *t = NULL, *iter;
-	unsigned long flags;
 
-	spin_lock_irqsave(&card->lock, flags);
-	list_for_each_entry(iter, &card->transaction_list, link) {
-		if (iter == transaction) {
-			if (!try_cancel_split_timeout(iter)) {
-				spin_unlock_irqrestore(&card->lock, flags);
-				goto timed_out;
+	scoped_guard(spinlock_irqsave, &card->lock) {
+		list_for_each_entry(iter, &card->transaction_list, link) {
+			if (iter == transaction) {
+				if (try_cancel_split_timeout(iter)) {
+					list_del_init(&iter->link);
+					card->tlabel_mask &= ~(1ULL << iter->tlabel);
+					t = iter;
+				}
+				break;
 			}
-			list_del_init(&iter->link);
-			card->tlabel_mask &= ~(1ULL << iter->tlabel);
-			t = iter;
-			break;
 		}
 	}
-	spin_unlock_irqrestore(&card->lock, flags);
 
-	if (t) {
-		if (!t->with_tstamp) {
-			t->callback.without_tstamp(card, rcode, NULL, 0, t->callback_data);
-		} else {
-			t->callback.with_tstamp(card, rcode, t->packet.timestamp, response_tstamp,
-						NULL, 0, t->callback_data);
-		}
-		return 0;
+	if (!t)
+		return -ENOENT;
+
+	if (!t->with_tstamp) {
+		t->callback.without_tstamp(card, rcode, NULL, 0, t->callback_data);
+	} else {
+		t->callback.with_tstamp(card, rcode, t->packet.timestamp, response_tstamp, NULL, 0,
+					t->callback_data);
 	}
 
- timed_out:
-	return -ENOENT;
+	return 0;
 }
 
 /*
@@ -121,16 +117,13 @@ static void split_transaction_timeout_callback(struct timer_list *timer)
 {
 	struct fw_transaction *t = from_timer(t, timer, split_timeout_timer);
 	struct fw_card *card = t->card;
-	unsigned long flags;
 
-	spin_lock_irqsave(&card->lock, flags);
-	if (list_empty(&t->link)) {
-		spin_unlock_irqrestore(&card->lock, flags);
-		return;
+	scoped_guard(spinlock_irqsave, &card->lock) {
+		if (list_empty(&t->link))
+			return;
+		list_del(&t->link);
+		card->tlabel_mask &= ~(1ULL << t->tlabel);
 	}
-	list_del(&t->link);
-	card->tlabel_mask &= ~(1ULL << t->tlabel);
-	spin_unlock_irqrestore(&card->lock, flags);
 
 	if (!t->with_tstamp) {
 		t->callback.without_tstamp(card, RCODE_CANCELLED, NULL, 0, t->callback_data);
@@ -143,20 +136,14 @@ static void split_transaction_timeout_callback(struct timer_list *timer)
 static void start_split_transaction_timeout(struct fw_transaction *t,
 					    struct fw_card *card)
 {
-	unsigned long flags;
+	guard(spinlock_irqsave)(&card->lock);
 
-	spin_lock_irqsave(&card->lock, flags);
-
-	if (list_empty(&t->link) || WARN_ON(t->is_split_transaction)) {
-		spin_unlock_irqrestore(&card->lock, flags);
+	if (list_empty(&t->link) || WARN_ON(t->is_split_transaction))
 		return;
-	}
 
 	t->is_split_transaction = true;
 	mod_timer(&t->split_timeout_timer,
 		  jiffies + card->split_timeout_jiffies);
-
-	spin_unlock_irqrestore(&card->lock, flags);
 }
 
 static u32 compute_split_timeout_timestamp(struct fw_card *card, u32 request_timestamp);
@@ -1015,7 +1002,6 @@ EXPORT_SYMBOL(fw_core_handle_request);
 void fw_core_handle_response(struct fw_card *card, struct fw_packet *p)
 {
 	struct fw_transaction *t = NULL, *iter;
-	unsigned long flags;
 	u32 *data;
 	size_t data_length;
 	int tcode, tlabel, source, rcode;
@@ -1054,26 +1040,23 @@ void fw_core_handle_response(struct fw_card *card, struct fw_packet *p)
 		break;
 	}
 
-	spin_lock_irqsave(&card->lock, flags);
-	list_for_each_entry(iter, &card->transaction_list, link) {
-		if (iter->node_id == source && iter->tlabel == tlabel) {
-			if (!try_cancel_split_timeout(iter)) {
-				spin_unlock_irqrestore(&card->lock, flags);
-				goto timed_out;
+	scoped_guard(spinlock_irqsave, &card->lock) {
+		list_for_each_entry(iter, &card->transaction_list, link) {
+			if (iter->node_id == source && iter->tlabel == tlabel) {
+				if (try_cancel_split_timeout(iter)) {
+					list_del_init(&iter->link);
+					card->tlabel_mask &= ~(1ULL << iter->tlabel);
+					t = iter;
+				}
+				break;
 			}
-			list_del_init(&iter->link);
-			card->tlabel_mask &= ~(1ULL << iter->tlabel);
-			t = iter;
-			break;
 		}
 	}
-	spin_unlock_irqrestore(&card->lock, flags);
 
 	trace_async_response_inbound((uintptr_t)t, card->index, p->generation, p->speed, p->ack,
 				     p->timestamp, p->header, data, data_length / 4);
 
 	if (!t) {
- timed_out:
 		fw_notice(card, "unsolicited response (source %x, tlabel %x)\n",
 			  source, tlabel);
 		return;