[LARTC] [Q]about u32 filter

[soyoung@xxxxxxxxxxxxxxx]

Hi, I have a question about u32 filter.

in u32_classify() function (located in net/sched/cls_u32.c), 
there is a memory address boundary check code : 

--

#if !defined(__i386__) && !defined(__mc68000__)
	if ((unsigned long)ptr & 3) { // ptr = skb->nh.raw
		printk("ptr error...returned -1\n");
		return -1;
	}
#endif

--

According to the code, it is error if ptr is not a multiple of 4 
except on the i386 or mc68000.  Why is this kind of code necessary? 
What kind of problem could happen if that code is removed 
on the other platform - arm or mips or etc..

SoYoung