From b2c0a2ac3e59f4764c59c23bd90b571e44256030 Mon Sep 17 00:00:00 2001
From: Stefan Richter <stefanr@s5r6.in-berlin.de>
Date: Thu, 15 Oct 2009 21:16:53 +0200
Subject: [PATCH] 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 <stefanr@s5r6.in-berlin.de>
---
drivers/firewire/core-cdev.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 1accfaf96c6f..e7290928a900 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -1299,7 +1299,23 @@ static int (* const ioctl_handlers[])(struct client *client, void *buffer) = {
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) != '#' ||
--
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