[PATCH] firewire: core: fix to update generation field in topology map

[PATCH] firewire: core: fix to update generation field in topology map

[Takashi Sakamoto]

The generation field of topology map is updated after initialized by zero.
The updated value of generation field is always zero, and is against
specification.

This commit fixes the bug.

Fixes: 7d138cb269db ("firewire: core: use spin lock specific to topology map")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 drivers/firewire/core-topology.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/firewire/core-topology.c b/drivers/firewire/core-topology.c
index 2f73bcd5696f..ed3ae8cdb0cd 100644
--- a/drivers/firewire/core-topology.c
+++ b/drivers/firewire/core-topology.c
@@ -441,12 +441,13 @@ static void update_topology_map(__be32 *buffer, size_t buffer_size, int root_nod
 				const u32 *self_ids, int self_id_count)
 {
 	__be32 *map = buffer;
+	u32 next_generation = be32_to_cpu(buffer[1]) + 1;
 	int node_count = (root_node_id & 0x3f) + 1;
 
 	memset(map, 0, buffer_size);
 
 	*map++ = cpu_to_be32((self_id_count + 2) << 16);
-	*map++ = cpu_to_be32(be32_to_cpu(buffer[1]) + 1);
+	*map++ = cpu_to_be32(next_generation);
 	*map++ = cpu_to_be32((node_count << 16) | self_id_count);
 
 	while (self_id_count--)
-- 
2.51.0

Re: [PATCH] firewire: core: fix to update generation field in topology map

[Takashi Sakamoto]

On Fri, Nov 14, 2025 at 11:44:21PM +0900, Takashi Sakamoto wrote:
> The generation field of topology map is updated after initialized by zero.
> The updated value of generation field is always zero, and is against
> specification.
> 
> This commit fixes the bug.
> 
> Fixes: 7d138cb269db ("firewire: core: use spin lock specific to topology map")
> Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
> ---
>  drivers/firewire/core-topology.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Applied to for-linus branch.


Regards

Takashi Sakamoto