firewire: fully initialize fw_transaction before marking it pending
In theory, card->flush_timer could already access a transaction between
fw_send_request()'s spin_unlock_irqrestore and the rest of what happens
in fw_send_request(). This would happen if the process which sends the
request is preempted and put to sleep right after spin_unlock_irqrestore
for longer than 100ms.
Therefore we fill in everything in struct fw_transaction at which the
flush_timer might look at before we lift the lock.
To do: Ensure that the timer does not pick up the transaction before
the time of the AT request event plus split transaction timeout.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/fw-transaction.c b/drivers/firewire/fw-transaction.c
index 40db807..7addfb3 100644
--- a/drivers/firewire/fw-transaction.c
+++ b/drivers/firewire/fw-transaction.c
@@ -279,11 +279,6 @@
card->current_tlabel = (card->current_tlabel + 1) & 0x1f;
card->tlabel_mask |= (1 << tlabel);
- list_add_tail(&t->link, &card->transaction_list);
-
- spin_unlock_irqrestore(&card->lock, flags);
-
- /* Initialize rest of transaction, fill out packet and send it. */
t->node_id = node_id;
t->tlabel = tlabel;
t->callback = callback;
@@ -294,6 +289,10 @@
speed, offset, payload, length);
t->packet.callback = transmit_complete_callback;
+ list_add_tail(&t->link, &card->transaction_list);
+
+ spin_unlock_irqrestore(&card->lock, flags);
+
card->driver->send_request(card, &t->packet);
}
EXPORT_SYMBOL(fw_send_request);