Re: [Qemu-devel] [Qemu-trivial] [PATCH v1 1/5] block/nand: Factor out common code

[Peter Crosthwaite <peter.crosthwaite@xilinx.com>]

Hi Michael,

On Wed, Jun 19, 2013 at 6:09 PM, Michael Tokarev <mjt@tls.msk.ru> wrote:
> 18.06.2013 15:08, peter.crosthwaite@xilinx.com wrote:
>> From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>>
>> Most of this computation of s->iolen is the same for both the if and
>> else paths here. Factor out the common parts outside the if.
>>
>> Cc: qemu-trivial@nongnu.org
>>
>> Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
>> ---
>>
>>  hw/block/nand.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/block/nand.c b/hw/block/nand.c
>> index 087ca14..6309f93 100644
>> --- a/hw/block/nand.c
>> +++ b/hw/block/nand.c
>> @@ -272,10 +272,10 @@ static void nand_command(NANDFlashState *s)
>>              break;
>>          offset = s->addr & ((1 << s->addr_shift) - 1);
>>          s->blk_load(s, s->addr, offset);
>> -        if (s->gnd)
>> -            s->iolen = (1 << s->page_shift) - offset;
>> -        else
>> -            s->iolen = (1 << s->page_shift) + (1 << s->oob_shift) - offset;
>> +        s->iolen = (1 << s->page_shift) - offset;
>> +        if (!s->gnd) {
>> +            s->iolen += 1 << s->oob_shift;
>> +        }
>
> Hm.  Can s->iolen become negative here?
>
> addr_shift can be either less or greather than page_shift.  When addr_shift
> is larger than page_shift (addr_shift=16, page_shift=11), offset may be up
> to 65535, in which case s->iolen may be -63487, even without additional
> oob_shift.
>
> I dunno if this is a concern, just.. asking.
>
> Besides, exactly the same expression is used in nand_getio() down this file,
> maybe a common function is in order? :)
>
> And looking at this file, I think it deserves some good type changes.  For
> example, all these _shift are unsigned, and most are actually used as masks,
> in form (1<<shift), instead of directly (except of erase_shift).
>

All sounds fair. Ill have another look in the context of type
changing, and factoring out some commonality. Your able to take P2
without conflict? :)

Regards,
Peter

> Thanks,
>
> /mjt
>