+25
−14
Loading
firewire: Fix for broken configrom updates in quick succession
Current implementation of ohci_set_config_rom() uses a deferred bus reset via fw_schedule_bus_reset(). If clients add multiple unit descriptors to the config_rom in quick succession, the deferred bus reset may not have fired before succeeding update requests have come in. This can lead to an incorrect partial update of the config_rom for both addition and removal of config_rom descriptors, as the ohci_set_config_rom() routine will return -EBUSY if a previous pending update has not been completed yet; the requested update just gets dropped on the floor. This patch recognizes that the "in-flight" update can be modified until it has been processed by the bus-reset, and the locking in the bus_reset_tasklet ensures that the update is done atomically with respect to modifications made by ohci_set_config_rom(). The -EBUSY error case is simply removed. [Stefan R: The bug always existed at least theoretically. But it became easy to trigger since 2.6.36 commit 02d37bed "firewire: core: integrate software-forced bus resets with bus management" which introduced long mandatory delays between janitorial bus resets.] Signed-off-by:Benjamin Buchalter <bj@mhlabs.com> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> (trivial style changes) Cc: <stable@kernel.org> # 2.6.36.y and newer