[PATCH 1/3] firewire: core: use workqueue to cancel all pending transactions on card removal

[Takashi Sakamoto]

When a card is being removed, all pending transactions are canceled by
calling fw_cancel_pending_transactions(). This function moves the entries
for unfinished transactions to a local list so that their callbacks can
be invoked without holding the transaction lock. However, this complicates
the management of pending transactions.

Use workqueue to invoke error callbacks for all pending transactions.

Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
---
 drivers/firewire/core-card.c        |  4 ++-
 drivers/firewire/core-transaction.c | 38 ++++++++++++-----------------
 2 files changed, 19 insertions(+), 23 deletions(-)

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index 83c29a487d86..a43fc3a278f2 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -811,7 +811,9 @@ void fw_core_remove_card(struct fw_card *card)
 	drain_workqueue(card->isoc_wq);
 	drain_workqueue(card->async_wq);
 	card->driver->disable(card);
-	fw_cancel_pending_transactions(card);
+
+	scoped_guard(spinlock_irqsave, &card->transactions.lock)
+		fw_cancel_pending_transactions(card);
 
 	scoped_guard(spinlock_irqsave, &card->lock)
 		fw_destroy_nodes(card);
diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index 96c86a5b81f9..31cc440d4218 100644
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -69,28 +69,6 @@ static void invoke_callback(struct fw_transaction *t, int rcode, u32 response_ts
 	}
 }
 
-// Must be called without holding card->transactions.lock.
-void fw_cancel_pending_transactions(struct fw_card *card)
-__must_not_hold(&card->transactions.lock)
-{
-	struct fw_transaction *t, *tmp;
-	LIST_HEAD(pending_list);
-
-	lockdep_assert_not_held(&card->transactions.lock);
-
-	scoped_guard(spinlock_irqsave, &card->transactions.lock) {
-		list_for_each_entry_safe(t, tmp, &card->transactions.list, link) {
-			if (try_cancel_split_timeout(t))
-				list_move(&t->link, &pending_list);
-		}
-	}
-
-	list_for_each_entry_safe(t, tmp, &pending_list, link) {
-		list_del(&t->link);
-		invoke_callback(t, RCODE_CANCELLED, 0, NULL, 0);
-	}
-}
-
 // card->transactions.lock must be acquired in advance.
 #define find_and_pop_transaction_entry(card, condition)			\
 ({									\
@@ -114,6 +92,22 @@ static void schedule_error_callback(struct fw_transaction *t, int rcode, u32 res
 	queue_work(t->card->async_wq, &t->error_work);
 }
 
+// Must be called without holding card->transactions.lock.
+void fw_cancel_pending_transactions(struct fw_card *card)
+__must_hold(&card->transactions.lock)
+{
+	struct fw_transaction *t, *tmp;
+
+	lockdep_assert_held(&card->transactions.lock);
+
+	list_for_each_entry_safe(t, tmp, &card->transactions.list, link) {
+		if (try_cancel_split_timeout(t)) {
+			remove_transaction_entry(card, t);
+			schedule_error_callback(t, RCODE_CANCELLED, 0);
+		}
+	}
+}
+
 /**
  * fw_cancel_transaction: cancel transaction.
  * @card:		interface where the transaction has been requested
-- 
2.53.0