2004-10-26 23:47:04

by Grant Coady

Subject: [PATCH TRIVIAL] 2.4.28-rc1 RFC remove three compiler warnings

Hi there,

Three compiler warnings are related and due to comparison of
an unsigned char against 256, resulting in these warnings:

vt.c: In function `do_kdsk_ioctl':
vt.c:166: warning: comparison is always false due to limited range of data type
vt.c: In function `do_kdgkb_ioctl':
vt.c:283: warning: comparison is always false due to limited range of data type
keyboard.c: In function `do_fn':
keyboard.c:640: warning: comparison is always true due to limited range of data type

Related constants:
include/linux/keyboard.h:#define MAX_NR_KEYMAPS 256
include/linux/keyboard.h:#define MAX_NR_FUNC 256
drivers/char/defkeymap.c:char *func_table[MAX_NR_FUNC] = {

Compiler: gcc (GCC) 3.3.4, system is slackware-10.0 on a pII box.

Is removing useless comparisions the correct solution?

Dot config, dmesg, patch files at:
http://users.netconnect.com.au/~gcoady/2.4.28-rc1/

Cheers,
Grant Coady.
--

diff -urN -X dontdiff linux-2.4.28-rc1-orig/drivers/char/keyboard.c linux-2.4.28-rc1/drivers/char/keyboard.c
--- linux-2.4.28-rc1-orig/drivers/char/keyboard.c 2003-11-29 05:26:20.000000000 +1100
+++ linux-2.4.28-rc1/drivers/char/keyboard.c 2004-10-26 19:02:24.000000000 +1000
@@ -637,11 +637,8 @@
{
if (up_flag)
return;
- if (value < SIZE(func_table)) {
- if (func_table[value])
- puts_queue(func_table[value]);
- } else
- printk(KERN_ERR "do_fn called with value=%d\n", value);
+ if (func_table[value])
+ puts_queue(func_table[value]);
}

static void do_pad(unsigned char value, char up_flag)
diff -urN -X dontdiff linux-2.4.28-rc1-orig/drivers/char/vt.c linux-2.4.28-rc1/drivers/char/vt.c
--- linux-2.4.28-rc1-orig/drivers/char/vt.c 2002-11-29 10:53:12.000000000 +1100
+++ linux-2.4.28-rc1/drivers/char/vt.c 2004-10-26 19:00:29.000000000 +1000
@@ -163,7 +163,7 @@

if (copy_from_user(&tmp, user_kbe, sizeof(struct kbentry)))
return -EFAULT;
- if (i >= NR_KEYS || s >= MAX_NR_KEYMAPS)
+ if (i >= NR_KEYS)
return -EINVAL;

switch (cmd) {
@@ -280,8 +280,6 @@
if (copy_from_user(&tmp, user_kdgkb, sizeof(struct kbsentry)))
return -EFAULT;
tmp.kb_string[sizeof(tmp.kb_string)-1] = '\0';
- if (tmp.kb_func >= MAX_NR_FUNC)
- return -EINVAL;
i = tmp.kb_func;

switch (cmd) {

2004-10-27 09:16:39

by O.Sezer

Subject: Re: [PATCH TRIVIAL] 2.4.28-rc1 RFC remove three compiler warnings

Grant:
This one's not that trivial, I think. Please see:
http://marc.theaimsgroup.com/?t=108462688000001&r=1&w=2
http://marc.theaimsgroup.com/?l=linux-kernel&m=108479097911074&w=2

Regards,
O. Sezer