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Commit b2c0a2ac authored by Stefan Richter's avatar Stefan Richter
Browse files

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: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent 19593ffd

drivers/firewire/core-cdev.c

+17 −1
Original line number Original line Diff line number Diff line
@@ -1299,7 +1299,23 @@ static int (* const ioctl_handlers[])(struct client *client, void *buffer) = { 
static int dispatch_ioctl(struct client *client,

static int dispatch_ioctl(struct client *client,

			  unsigned int cmd, void __user *arg)

			  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;

	int ret;





	if (_IOC_TYPE(cmd) != '#' ||

	if (_IOC_TYPE(cmd) != '#' ||