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 <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index 667603a..543fcca 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -461,11 +461,11 @@
/*
- * 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 @@
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_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 @@
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);