Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: (26 commits)
  firewire: fw-sbp2: Use sbp2 device-provided mgt orb timeout for logins
  firewire: fw-sbp2: increase login orb reply timeout, fix "failed to login"
  firewire: replace subtraction with bitwise and
  firewire: fw-core: react on bus resets while the config ROM is being fetched
  firewire: enforce access order between generation and node ID, fix "giving up on config rom"
  firewire: fw-cdev: use device generation, not card generation
  firewire: fw-sbp2: use device generation, not card generation
  firewire: fw-sbp2: try to increase reconnect_hold (speed up reconnection)
  firewire: fw-sbp2: skip unnecessary logout
  firewire vs. ieee1394: clarify MAINTAINERS
  firewire: fw-ohci: Dynamically allocate buffers for DMA descriptors
  firewire: fw-ohci: CycleTooLong interrupt management
  firewire: Fix extraction of source node id
  firewire: fw-ohci: Bug fixes for packet-per-buffer support
  firewire: fw-ohci: Fix for dualbuffer three-or-more buffers
  firewire: fw-sbp2: remove unused misleading macro
  firewire: fw-sbp2: prepare for s/g chaining
  firewire: fw-sbp2: refactor workq and kref handling
  ieee1394: ohci1394: don't schedule IT tasklets on IR events
  ieee1394: sbp2: raise default transfer size limit
  ...

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+ * to an outdated node_id if the generation was updated in the meantime due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;