Re: [Qemu-devel] [PATCH] Use DMADirection type for dma_bdrv_io

[Hannes Reinecke <hare@suse.de>]

On 02/22/2012 10:54 AM, Andreas Färber wrote:
> Am 22.02.2012 02:11, schrieb David Gibson:
>> On Tue, Feb 21, 2012 at 10:09:01AM +0100, Kevin Wolf wrote:
>>> Am 21.02.2012 09:35, schrieb Paolo Bonzini:
>>>> On 02/20/2012 11:50 AM, Alexander Graf wrote:
>>>>>>>     DMAAIOCB *dbs = qemu_aio_get(&dma_aio_pool, bs, cb, opaque);
>>>>>>>
>>>>>>> -    trace_dma_bdrv_io(dbs, bs, sector_num, to_dev);
>>>>>>> +    trace_dma_bdrv_io(dbs, bs, sector_num, dir);
>>>>> Was the trace wrong before or is it now? I don't see its definition changed anywhere.
>>>>
>>>> Not sure what you mean. :)
>>>
>>> trace-events:
>>>
>>> dma_bdrv_io(void *dbs, void *bs, int64_t sector_num, bool to_dev)
>>> "dbs=%p bs=%p sector_num=%" PRId64 " to_dev=%d"
>>
>> Ah, damnit.  Didn't find that file.  I'll resubmit with trace-events
>> updated too.
>>
>>> to_dev is declared bool here, and it should also be renamed to dir (the
>>> unfortunate thing about DMADirection is that it swaps 0 and 1 compared
>>> to bool to_dev... We need to check carefully that all occurrences have
>>> been caught.)
>>
>> Yeah.  And even more unfortunate that afaict there's no way to make
>> gcc warn on enum<->bool conversions.  Still there are only about 4
>> callers of dma_bdrv_io() - nearly everything uses the
>> dma_bdrv_{read,write}() wrappers - so I'm confident I got them all.
> 
> Re all occurrences: megasas might be affected by such a change, too
> (patch on the list).
> 
Nope. megasas is using the scsi interface for reading/writing,
so it should be insulated against this kind of change.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
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