Date: Thu, 15 Oct 2009 21:16:53 +0200 (CEST) From: Stefan Richter Subject: firewire: cdev: reduce stack usage by ioctl_dispatch Replace a hardcoded buffer size by a sizeof union {}. This shrinks the stack-allocated ioctl argument buffer from 256 to 40 bytes. (This is not much, but subsequent stack usage particularly by the queue_iso ioctl handler adds up.) The new form is also easier to keep up to date than a hardcoded size if more ioctls are added. Signed-off-by: Stefan Richter --- drivers/firewire/core-cdev.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) Index: linux-2.6.31/drivers/firewire/core-cdev.c =================================================================== --- linux-2.6.31.orig/drivers/firewire/core-cdev.c +++ linux-2.6.31/drivers/firewire/core-cdev.c @@ -1299,7 +1299,23 @@ static int (* const ioctl_handlers[])(st static int dispatch_ioctl(struct client *client, unsigned int cmd, void __user *arg) { - char buffer[256]; + char buffer[sizeof(union { + struct fw_cdev_get_info _00; + struct fw_cdev_send_request _01; + struct fw_cdev_allocate _02; + struct fw_cdev_deallocate _03; + struct fw_cdev_send_response _04; + struct fw_cdev_initiate_bus_reset _05; + struct fw_cdev_add_descriptor _06; + struct fw_cdev_remove_descriptor _07; + struct fw_cdev_create_iso_context _08; + struct fw_cdev_queue_iso _09; + struct fw_cdev_start_iso _0a; + struct fw_cdev_stop_iso _0b; + struct fw_cdev_get_cycle_timer _0c; + struct fw_cdev_allocate_iso_resource _0d; + struct fw_cdev_send_stream_packet _13; + })]; int ret; if (_IOC_TYPE(cmd) != '#' ||