On Tue, Aug 16, 2011 at 2:35 PM, Boaz Harrosh <bharrosh@xxxxxxxxxxx> wrote:
> On 08/16/2011 02:09 PM, Nicholas A. Bellinger wrote:
> <snip>
>>> +static enum dma_data_direction tcm_qla2xxx_mapping_dir(struct se_cmd *se_cmd)
>>> +{
>>> + if (se_cmd->t_tasks_bidi)
>>> + return DMA_BIDIRECTIONAL;
>>> +
>>
>> Mmmm, I don't think this is correct. It's my understanding that
>> DMA_BIDIRECTIONAL is different from SCSI bidi operation, and that the
>> individual bidi payloads should be retaining their individual
>> DMA_FROM_DEVICE and DMA_TO_DEVICE usage.. (Boaz CC'ed)
>
> Yes! DMA_BIDIRECTIONAL means that the same direct-access buffer could
> be written to and read from at the same time. For example a shared
> host-DSP buffer could be that case. It tells the (true) IOMMU to
> let both type of access on this single buffer.
OK, fair enough. However I don't see where the cmd->data_direction gets
changed from TO_DEVICE to FROM_DEVICE for the two phases. How does
that happen?
Do bidi commands work at all with the qla2xxx target?
- R.
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