Date: Tue, 16 Jun 2009 19:15:25 +0200 (CEST) From: Stefan Richter Subject: firewire: core: fix iso context shutdown on card removal If isochronous contexts existed when firewire-ohci was unloaded, the core iso shutdown functions crashed with NULL dereferences, and buffers etc. weren't released. How the fix works: We first copy the card driver's iso shutdown hooks into the dummy driver, then fw_destroy_nodes notifies upper layers of devices going away, these should shut down (including their iso contexts), wait_for_completion(&card->done) will be triggered after upper layers gave up all fw_device references, after which the card driver's shutdown proceeds. Signed-off-by: Stefan Richter --- drivers/firewire/core-card.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) Index: b/drivers/firewire/core-card.c =================================================================== --- a/drivers/firewire/core-card.c +++ b/drivers/firewire/core-card.c @@ -461,11 +461,11 @@ EXPORT_SYMBOL(fw_card_add); /* - * The next few functions implements a dummy driver that use once a - * card driver shuts down an fw_card. This allows the driver to - * cleanly unload, as all IO to the card will be handled by the dummy - * driver instead of calling into the (possibly) unloaded module. The - * dummy driver just fails all IO. + * The next few functions implement a dummy driver that is used once a card + * driver shuts down an fw_card. This allows the driver to cleanly unload, + * as all IO to the card will be handled (and failed) by the dummy driver + * instead of calling into the module. Only functions for iso context + * shutdown still need to be provided by the card driver. */ static int dummy_enable(struct fw_card *card, u32 *config_rom, size_t length) @@ -512,7 +512,7 @@ static int dummy_enable_phys_dma(struct return -ENODEV; } -static struct fw_card_driver dummy_driver = { +static const struct fw_card_driver dummy_driver_template = { .enable = dummy_enable, .update_phy_reg = dummy_update_phy_reg, .set_config_rom = dummy_set_config_rom, @@ -531,6 +531,8 @@ void fw_card_release(struct kref *kref) void fw_core_remove_card(struct fw_card *card) { + struct fw_card_driver dummy_driver = dummy_driver_template; + card->driver->update_phy_reg(card, 4, PHY_LINK_ACTIVE | PHY_CONTENDER, 0); fw_core_initiate_bus_reset(card, 1); @@ -539,7 +541,9 @@ void fw_core_remove_card(struct fw_card list_del_init(&card->link); mutex_unlock(&card_mutex); - /* Set up the dummy driver. */ + /* Switch off most of the card driver interface. */ + dummy_driver.free_iso_context = card->driver->free_iso_context; + dummy_driver.stop_iso = card->driver->stop_iso; card->driver = &dummy_driver; fw_destroy_nodes(card);