From: =?utf-8?q?Kristian_H=C3=B8gsberg?= Subject: [PATCH 13/21] firewire: Use only a wait queue and terminate poll and read on device removal. Date: Wed, 7 Mar 2007 12:12:48 -0500 Drop the event list semaphore and only use the wait queue and the list to synchronize queue access. Break out of a poll or read whenever the device is disconnected. Signed-off-by: Kristian Høgsberg Signed-off-by: Stefan Richter --- drivers/firewire/fw-device-cdev.c | 80 +++++++++++++++++++++++------------- drivers/firewire/fw-device.c | 1 + drivers/firewire/fw-device.h | 7 +++ 3 files changed, 59 insertions(+), 29 deletions(-) diff --git a/drivers/firewire/fw-device-cdev.c b/drivers/firewire/fw-device-cdev.c index 54ef27b..2d84284 100644 --- a/drivers/firewire/fw-device-cdev.c +++ b/drivers/firewire/fw-device-cdev.c @@ -76,7 +76,6 @@ struct client { struct list_head request_list; u32 request_serial; struct list_head event_list; - struct semaphore event_list_sem; wait_queue_head_t wait; struct fw_iso_context *iso_context; @@ -114,7 +113,6 @@ static int fw_device_op_open(struct inode *inode, struct file *file) client->device = fw_device_get(device); INIT_LIST_HEAD(&client->event_list); - sema_init(&client->event_list_sem, 0); INIT_LIST_HEAD(&client->handler_list); INIT_LIST_HEAD(&client->request_list); spin_lock_init(&client->lock); @@ -142,38 +140,41 @@ static void queue_event(struct client *client, struct event *event, spin_lock_irqsave(&client->lock, flags); list_add_tail(&event->link, &client->event_list); - - up(&client->event_list_sem); wake_up_interruptible(&client->wait); spin_unlock_irqrestore(&client->lock, flags); } -static int dequeue_event(struct client *client, char __user *buffer, size_t count) +static int +dequeue_event(struct client *client, char __user *buffer, size_t count) { unsigned long flags; struct event *event; size_t size, total; - int i, retval = -EFAULT; + int i, retval; - if (down_interruptible(&client->event_list_sem) < 0) - return -EINTR; + retval = wait_event_interruptible(client->wait, + !list_empty(&client->event_list) || + fw_device_is_shutdown(client->device)); + if (retval < 0) + return retval; - spin_lock_irqsave(&client->lock, flags); + if (list_empty(&client->event_list) && + fw_device_is_shutdown(client->device)) + return -ENODEV; + spin_lock_irqsave(&client->lock, flags); event = container_of(client->event_list.next, struct event, link); list_del(&event->link); - spin_unlock_irqrestore(&client->lock, flags); - if (buffer == NULL) - goto out; - total = 0; for (i = 0; i < ARRAY_SIZE(event->v) && total < count; i++) { size = min(event->v[i].size, count - total); - if (copy_to_user(buffer + total, event->v[i].data, size)) + if (copy_to_user(buffer + total, event->v[i].data, size)) { + retval = -EFAULT; goto out; + } total += size; } retval = total; @@ -209,6 +210,22 @@ fill_bus_reset_event(struct fw_cdev_event_bus_reset *event, } static void +for_each_client(struct fw_device *device, + void (*callback)(struct client *client)) +{ + struct fw_card *card = device->card; + struct client *c; + unsigned long flags; + + spin_lock_irqsave(&card->lock, flags); + + list_for_each_entry(c, &device->client_list, link) + callback(c); + + spin_unlock_irqrestore(&card->lock, flags); +} + +static void queue_bus_reset_event(struct client *client) { struct bus_reset *bus_reset; @@ -228,16 +245,17 @@ queue_bus_reset_event(struct client *client) void fw_device_cdev_update(struct fw_device *device) { - struct fw_card *card = device->card; - struct client *c; - unsigned long flags; - - spin_lock_irqsave(&card->lock, flags); + for_each_client(device, queue_bus_reset_event); +} - list_for_each_entry(c, &device->client_list, link) - queue_bus_reset_event(c); +static void wake_up_client(struct client *client) +{ + wake_up_interruptible(&client->wait); +} - spin_unlock_irqrestore(&card->lock, flags); +void fw_device_cdev_remove(struct fw_device *device) +{ + for_each_client(device, wake_up_client); } static int ioctl_get_info(struct client *client, void __user *arg) @@ -731,8 +749,9 @@ static int fw_device_op_mmap(struct file *file, struct vm_area_struct *vma) static int fw_device_op_release(struct inode *inode, struct file *file) { struct client *client = file->private_data; - struct address_handler *h, *next; + struct address_handler *h, *next_h; struct request *r, *next_r; + struct event *e, *next_e; unsigned long flags; if (client->buffer.pages) @@ -741,7 +760,7 @@ static int fw_device_op_release(struct inode *inode, struct file *file) if (client->iso_context) fw_iso_context_destroy(client->iso_context); - list_for_each_entry_safe(h, next, &client->handler_list, link) { + list_for_each_entry_safe(h, next_h, &client->handler_list, link) { fw_core_remove_address_handler(&h->handler); kfree(h); } @@ -755,8 +774,8 @@ static int fw_device_op_release(struct inode *inode, struct file *file) /* TODO: wait for all transactions to finish so * complete_transaction doesn't try to queue up responses * after we free client. */ - while (!list_empty(&client->event_list)) - dequeue_event(client, NULL, 0); + list_for_each_entry_safe(e, next_e, &client->event_list, link) + kfree(e); spin_lock_irqsave(&client->device->card->lock, flags); list_del(&client->link); @@ -771,13 +790,16 @@ static int fw_device_op_release(struct inode *inode, struct file *file) static unsigned int fw_device_op_poll(struct file *file, poll_table * pt) { struct client *client = file->private_data; + unsigned int mask = 0; poll_wait(file, &client->wait, pt); + if (fw_device_is_shutdown(client->device)) + mask |= POLLHUP | POLLERR; if (!list_empty(&client->event_list)) - return POLLIN | POLLRDNORM; - else - return 0; + mask |= POLLIN | POLLRDNORM; + + return mask; } const struct file_operations fw_device_ops = { diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c index 4ade867..4877cdb 100644 --- a/drivers/firewire/fw-device.c +++ b/drivers/firewire/fw-device.c @@ -453,6 +453,7 @@ static void fw_device_shutdown(struct work_struct *work) idr_remove(&fw_device_idr, minor); up_write(&fw_bus_type.subsys.rwsem); + fw_device_cdev_remove(device); device_remove_file(&device->device, &config_rom_attribute); device_for_each_child(&device->device, NULL, shutdown_unit); device_unregister(&device->device); diff --git a/drivers/firewire/fw-device.h b/drivers/firewire/fw-device.h index 1a3655b..ba0e246 100644 --- a/drivers/firewire/fw-device.h +++ b/drivers/firewire/fw-device.h @@ -53,11 +53,18 @@ fw_device(struct device *dev) return container_of(dev, struct fw_device, device); } +static inline int +fw_device_is_shutdown(struct fw_device *device) +{ + return atomic_read(&device->state) == FW_DEVICE_SHUTDOWN; +} + struct fw_device *fw_device_get(struct fw_device *device); void fw_device_put(struct fw_device *device); int fw_device_enable_phys_dma(struct fw_device *device); void fw_device_cdev_update(struct fw_device *device); +void fw_device_cdev_remove(struct fw_device *device); struct fw_device *fw_device_from_devt(dev_t devt); extern int fw_cdev_major;