diff options
Diffstat (limited to 'drivers/firewire/fw-device.h')
-rw-r--r-- | drivers/firewire/fw-device.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/firewire/fw-device.h b/drivers/firewire/fw-device.h index 894d4a92a18e..0854fe2bc110 100644 --- a/drivers/firewire/fw-device.h +++ b/drivers/firewire/fw-device.h @@ -35,6 +35,18 @@ struct fw_attribute_group { struct attribute *attrs[11]; }; +/* + * Note, fw_device.generation always has to be read before fw_device.node_id. + * Use SMP memory barriers to ensure this. Otherwise requests will be sent + * to an outdated node_id if the generation was updated in the meantime due + * to a bus reset. + * + * Likewise, fw-core will take care to update .node_id before .generation so + * that whenever fw_device.generation is current WRT the actual bus generation, + * fw_device.node_id is guaranteed to be current too. + * + * The same applies to fw_device.card->node_id vs. fw_device.generation. + */ struct fw_device { atomic_t state; struct fw_node *node; |