firewire: cdev: fix fw_cdev_event_bus_reset.bm_node_id

Fix an obscure ABI feature that is a bit of a hassle to implement.
However, somebody put it into the ABI, so let's fill in a sensible
value there.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 9 insertions, 3 deletions

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index 11fc81500f82..6c316cfe70c4 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -239,7 +239,7 @@ static void fw_card_bm_work(struct work_struct *work)
         struct fw_card *card = container_of(work, struct fw_card, work.work);
         struct fw_device *root_device;
         struct fw_node *root_node;
-        int root_id, new_root_id, irm_id, local_id;
+        int root_id, new_root_id, irm_id, bm_id, local_id;
         int gap_count, generation, grace, rcode;
         bool do_reset = false;
         bool root_device_is_running;
@@ -301,9 +301,15 @@ static void fw_card_bm_work(struct work_struct *work)
                         /* Another bus reset, BM work has been rescheduled. */
                         goto out;
 
-                if (rcode == RCODE_COMPLETE &&
-                    card->bm_transaction_data[0] != cpu_to_be32(0x3f)) {
+                bm_id = be32_to_cpu(card->bm_transaction_data[0]);
 
+                spin_lock_irq(&card->lock);
+                if (rcode == RCODE_COMPLETE && generation == card->generation)
+                        card->bm_node_id =
+                            bm_id == 0x3f ? local_id : 0xffc0 | bm_id;
+                spin_unlock_irq(&card->lock);
+
+                if (rcode == RCODE_COMPLETE && bm_id != 0x3f) {
                         /* Somebody else is BM.  Only act as IRM. */
                         if (local_id == irm_id)
                                 allocate_broadcast_channel(card, generation);