From 459f79235d8faa0050180c7e0c7bb4b2b52cbdfd Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Sat, 24 May 2008 16:50:22 +0200 Subject: [PATCH] firewire: clean up fw_card reference counting MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This is a functionally equivalent replacement of the current reference counting of struct fw_card instances. It only converts it to common idioms as suggested by Kristian Høgsberg: - struct kref replaces atomic_t as the counter. - wait_for_completion is used to wait for all card users to complete. BTW, it may make sense to count card->flush_timer and card->work as card users too. Signed-off-by: Stefan Richter --- drivers/firewire/fw-card.c | 30 ++++++++++++++++++++---------- drivers/firewire/fw-device.c | 5 ++--- drivers/firewire/fw-transaction.h | 20 ++++++++++++++++++-- 3 files changed, 40 insertions(+), 15 deletions(-) diff --git a/drivers/firewire/fw-card.c b/drivers/firewire/fw-card.c index 1332b66ae0..da873d795a 100644 --- a/drivers/firewire/fw-card.c +++ b/drivers/firewire/fw-card.c @@ -16,12 +16,15 @@ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ -#include -#include +#include +#include #include #include +#include +#include +#include #include -#include + #include "fw-transaction.h" #include "fw-topology.h" #include "fw-device.h" @@ -396,7 +399,6 @@ fw_card_initialize(struct fw_card *card, const struct fw_card_driver *driver, { static atomic_t index = ATOMIC_INIT(-1); - atomic_set(&card->device_count, 0); card->index = atomic_inc_return(&index); card->driver = driver; card->device = device; @@ -405,6 +407,8 @@ fw_card_initialize(struct fw_card *card, const struct fw_card_driver *driver, card->color = 0; card->broadcast_channel = BROADCAST_CHANNEL_INITIAL; + kref_init(&card->kref); + init_completion(&card->done); INIT_LIST_HEAD(&card->transaction_list); spin_lock_init(&card->lock); setup_timer(&card->flush_timer, @@ -506,6 +510,14 @@ static struct fw_card_driver dummy_driver = { .enable_phys_dma = dummy_enable_phys_dma, }; +void +fw_card_release(struct kref *kref) +{ + struct fw_card *card = container_of(kref, struct fw_card, kref); + + complete(&card->done); +} + void fw_core_remove_card(struct fw_card *card) { @@ -521,12 +533,10 @@ fw_core_remove_card(struct fw_card *card) card->driver = &dummy_driver; fw_destroy_nodes(card); - /* - * Wait for all device workqueue jobs to finish. Otherwise the - * firewire-core module could be unloaded before the jobs ran. - */ - while (atomic_read(&card->device_count) > 0) - msleep(100); + + /* Wait for all users, especially device workqueue jobs, to finish. */ + fw_card_put(card); + wait_for_completion(&card->done); cancel_delayed_work_sync(&card->work); fw_flush_transactions(card); diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c index d9c8daf7ae..0855fb5568 100644 --- a/drivers/firewire/fw-device.c +++ b/drivers/firewire/fw-device.c @@ -168,7 +168,7 @@ static void fw_device_release(struct device *dev) fw_node_put(device->node); kfree(device->config_rom); kfree(device); - atomic_dec(&card->device_count); + fw_card_put(card); } int fw_device_enable_phys_dma(struct fw_device *device) @@ -946,8 +946,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event) */ device_initialize(&device->device); atomic_set(&device->state, FW_DEVICE_INITIALIZING); - atomic_inc(&card->device_count); - device->card = card; + device->card = fw_card_get(card); device->node = fw_node_get(node); device->node_id = node->node_id; device->generation = card->generation; diff --git a/drivers/firewire/fw-transaction.h b/drivers/firewire/fw-transaction.h index 219094e385..2ae1b0d6cb 100644 --- a/drivers/firewire/fw-transaction.h +++ b/drivers/firewire/fw-transaction.h @@ -19,14 +19,15 @@ #ifndef __fw_transaction_h #define __fw_transaction_h +#include #include #include #include +#include #include #include #include #include -#include #define TCODE_IS_READ_REQUEST(tcode) (((tcode) & ~1) == 4) #define TCODE_IS_BLOCK_PACKET(tcode) (((tcode) & 1) != 0) @@ -219,7 +220,8 @@ extern struct bus_type fw_bus_type; struct fw_card { const struct fw_card_driver *driver; struct device *device; - atomic_t device_count; + struct kref kref; + struct completion done; int node_id; int generation; @@ -260,6 +262,20 @@ struct fw_card { int bm_generation; }; +static inline struct fw_card *fw_card_get(struct fw_card *card) +{ + kref_get(&card->kref); + + return card; +} + +void fw_card_release(struct kref *kref); + +static inline void fw_card_put(struct fw_card *card) +{ + kref_put(&card->kref, fw_card_release); +} + /* * The iso packet format allows for an immediate header/payload part * stored in 'header' immediately after the packet info plus an -- 2.39.5