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path: root/drivers/firewire/nosy.c
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Diffstat (limited to 'drivers/firewire/nosy.c')
-rw-r--r--drivers/firewire/nosy.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/firewire/nosy.c b/drivers/firewire/nosy.c
index 5fd6a60b6741..88ed971e32c0 100644
--- a/drivers/firewire/nosy.c
+++ b/drivers/firewire/nosy.c
@@ -346,6 +346,7 @@ nosy_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
struct client *client = file->private_data;
spinlock_t *client_list_lock = &client->lynx->client_list_lock;
struct nosy_stats stats;
+ int ret;
switch (cmd) {
case NOSY_IOC_GET_STATS:
@@ -360,11 +361,15 @@ nosy_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
return 0;
case NOSY_IOC_START:
+ ret = -EBUSY;
spin_lock_irq(client_list_lock);
- list_add_tail(&client->link, &client->lynx->client_list);
+ if (list_empty(&client->link)) {
+ list_add_tail(&client->link, &client->lynx->client_list);
+ ret = 0;
+ }
spin_unlock_irq(client_list_lock);
- return 0;
+ return ret;
case NOSY_IOC_STOP:
spin_lock_irq(client_list_lock);