[PATCH] NVMe: Add rw_page support

[axboe@kernel.dk (Jens Axboe)]

On 2014-11-14 16:04, Keith Busch wrote:
> On Fri, 14 Nov 2014, Jens Axboe wrote:
>> On 11/14/2014 03:50 PM, Keith Busch wrote:
>>> But nvme_cmd_info does not contain the opcode. I do have the struct
>>> request here, and I can certainly pull the data direction from its
>>> cmd_flags, so thanks for the suggestion!
>>>
>>> Now I wonder if there's something else unused in a request that I
>>> can repurpose to save the dma_addr_t in so I don't add it in the
>>> nvme_cmd_info...
>>
>> For the rw_page path, you don't use ->special to store the iod. So you
>> could use that... That might break for 32-bit platforms and 64-bit DMA,
>> though. If you really want to get nasty, ->__cmd is 16 bytes of unused
>> goodness as well, though I do want to make that one dynamically
>> allocated for the queues that need it.
>
> Ah, but I already got req->special pointing to the page. Maybe we can
> union another field with a new "special_2" field.

Since you are the request allocator, you can use ->end_io_data as well.

-- 
Jens Axboe