Re: Fwd: [PATCH v7 1/2] x86: Add Isolated Memory Regions for Quark X1000

[Bryan O'Donoghue]

On 30/01/15 12:55, Bryan O'Donoghue wrote:
> Oops.
>
> Hit reply not reply-all

On 30/01/15 12:03, Andy Shevchenko wrote:
>> +               return -ENOMEM;
>
> When CONFIG_DEBUGFS=n, you will get error pointer here, which is not 
NULL.
>
> So, the proper check is
> if (IS_ERR())
>   return PTR_ERR();
> if (!file)
>   return -ENOMEM;

Yeah I saw that. Also saw that most other code doesn't bother trapping
those return values - so skipped it.
No issue adding.

>
>> +               } else {
>> +                       reg = i;
>
> Do we go always through all IMRs and choose the last one?
> If no, break is missed here.

Yep - we always choose the last one.


>> +               }
>> +       }
>> +
>> +       /* Error out if we have no free IMR entries. */
>> +       if (reg == -1) {
>> +               ret = -ENODEV;
>
> -ENOMEM ? Like you said there is no *free* IMR.

OK

>> + * imr_remove_range(0, size, base); delete IMR at index 0 base/size 
ignored.
>> + * imr_remove_range(-1, base, size); delete IMR from base to base+size.
>
> (size, base) or (base, size) ?

base, size that's a documentation typo :)

>> +
>> +       ret = imr_check_params(base, size);
>> +       if (ret == -EINVAL || (ret == -ENOMEM && reg == -1))
>
> reg base size (0 correct, 1 wrong):
>
> 0 0 0 Ãââ which should be used? what is the priority?
> 0 x 1 Ãââ index
> 0 1 x Ãââ index
> 1 0 0 Ãââ address
> 1 0 1 Ãââ an error
> 1 1 1 Ãââ an error
>
> Thus, could it be simpler? Like
> if (reg < 0 && ret) ?

ret will be EINVAL for unaligned base or size
ret will be ENOMEM when reg == -1 and size == 0

I could probably write it like this to make it clearer
(ret == -EINVAL || (reg == -1 && size == 0)
	return -EINVAL;

traps unaligned input - for address range tear-down
traps zero sized - for address range tear-down

Allows index based teardown i.e. reg >= 0

> if (ret)
>
>> +               pr_warn("debugfs register failed!\n");
>
> Do we actually need this? Or move it to debug level.

It was your suggestion @ a previous review ....

> Here is the mix of kernel levels. What about to align them?
>
> For example I doubt we need to distinguish messages by level:
>
> pr_info();
> vprintk(KERN_INFO fmt, ÃâÂ);

OK fine.

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