Re: linux-next: Tree for July 30

Linus Torvalds
2008-08-01T19:13:13Z

Ok, I apparently missed this whole subthread yesterday, only getting back
to it when going over my old queues.

On Thu, 31 Jul 2008, Dmitry Torokhov wrote:
>
> Input: paper over a bug in Synaptics X driver

Yeah, it's not pretty, but how about moving that EV_KEY thing into the
switch() statement? Also, the printk could certainly be a bit more useful.

But before doing _any_ of that, the first thing to do should be to not
have that four-deep indentation by just splitting that horrible function
up a bit.

IOW, start off with a patch like the appended, and _then_ add the special
case handling to the EV_KEY thing. It would probably be most easily done
by just literally limiting "len" to OLD_KEY_MAX. Something like

#define OLD_KEY_MAX 0x1ff
...
case EV_KEY:
bits = dev->keybit;
len = KEY_MAX;
/* Hacky workaround for old bug in Xorg */
if (buf_len == OLD_KEY_MAX)
len = OLD_KEY_MAX;
break;
...

or similar.

Yeah, it's not pretty, but pragmatism before beauty.

Linus
---
drivers/input/evdev.c | 44 ++++++++++++++++++++++++--------------------
1 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 2d65411..ef8c2ed 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -647,6 +647,28 @@ static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
return copy_to_user(p, str, len) ? -EFAULT : len;
}

+static int handle_eviocgbit(struct input_dev *dev, unsigned int cmd, void __user *p, int compat_mode)
+{
+ unsigned long *bits;
+ int len;
+
+ switch (_IOC_NR(cmd) & EV_MAX) {
+
+ case 0: bits = dev->evbit; len = EV_MAX; break;
+ case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
+ case EV_REL: bits = dev->relbit; len = REL_MAX; break;
+ case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
+ case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
+ case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
+ case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
+ case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
+ case EV_SW: bits = dev->swbit; len = SW_MAX; break;
+ default: return -EINVAL;
+ }
+ return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
+}
+
+
static long evdev_do_ioctl(struct file *file, unsigned int cmd,
void __user *p, int compat_mode)
{
@@ -733,26 +755,8 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,

if (_IOC_DIR(cmd) == _IOC_READ) {

- if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {
-
- unsigned long *bits;
- int len;
-
- switch (_IOC_NR(cmd) & EV_MAX) {
-
- case 0: bits = dev->evbit; len = EV_MAX; break;
- case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
- case EV_REL: bits = dev->relbit; len = REL_MAX; break;
- case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
- case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
- case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
- case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
- case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
- case EV_SW: bits = dev->swbit; len = SW_MAX; break;
- default: return -EINVAL;
- }
- return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
- }
+ if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
+ return handle_eviocgbit(dev, cmd, p, compat_mode);

if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),