Re: 2.6.14 kernels and above copy_to_user stupidity with IRQ disabled check

["Jeff V. Merkey" <jmerkey@wolfmountaingroup.com>]

Phillip Susi wrote:

> jmerkey@ns1.utah-nac.org wrote:
>
>> OK.  Got it.  I guess I need to restructure.  And BTW, This was a 
>> code fragment
>> only, the spinlock gets released when -EFAULT is called -- was just 
>> an example.
>>
>> Jeff
>
>
> Unless you have redefined EFAULT in some strange and hideous way, it 
> is not "called" and doesn't free the spinlock.  EFAULT is defined as a 
> literal integer, so you're just returning a number without freeing the 
> spinlock.
>
> If you have redefined EFAULT to a macro function call or whatever, 
> then don't do that, it's REALLY horrible coding practice.
>
>
No.  I posted a code fragment as an example.  Here's the actual code:

int dump_regen(VIRTUAL_SETUP *s, ULONG count)
{
    register int i = 0;
    VIRTUAL_SETUP *v;
                                                                                

    spin_lock_irqsave(&regen_lock, regen_flags);
    v = regen_head;
    while (v)
    {
       if (i >= count)
       {
          spin_unlock_irqrestore(&regen_lock, regen_flags);
          return -EFAULT;
       }
                                                                                

       err = copy_to_user(&s[i++], v, sizeof(VIRTUAL_SETUP));
       if (err)
       {         
           spin_unlock_irqrestore(&regen_lock, regen_flags);
           return err;
       }

       v = v->next;
    }
    spin_unlock_irqrestore(&regen_lock, regen_flags);
    return 0;
}

Needless to say, this has been restructured to this:

int dump_regen(VIRTUAL_SETUP *s, ULONG count)
{
    register int i = 0;
    VIRTUAL_SETUP *v;
                                                                                

    spin_lock_irqsave(&regen_lock, regen_flags);
    v = regen_head;
    while (v)
    {
       if (i >= count)
       {
          spin_unlock_irqrestore(&regen_lock, regen_flags);
          return 0;
       }
                                                                                

       P_Copy(&s[i++], v, sizeof(VIRTUAL_SETUP));
       v = v->next;
    }
    spin_unlock_irqrestore(&regen_lock, regen_flags);
    return 0;
}
                                                                                

Jeff