[patch] NVMe: return an error code if blk_mq_alloc_tag_set() fails

[Jens Axboe]

On 01/22/2015 04:11 PM, Keith Busch wrote:
> On Thu, 22 Jan 2015, Jens Axboe wrote:
>> On 01/22/2015 09:48 AM, Keith Busch wrote:
>>> Should we bail on the device if tagset allocation fails? If so, the
>>> patch
>>> is good, but I thought it was a concious descision to not return error
>>> here so the controller can be managed. Capabilities would be limited
>>> and a failure here probably means there's a bigger problem, so I'm okay
>>> either way.
>>
>> That's a good point, you could still send admin IO through the ioctls
>> even if this fails. Looking at the rest of the function, the error
>> handling is a bit strange. If we fail the nvme_identify(), we'll just
>> march on. If the next works, we're good, we return success. But if the
>> failed one happens to be the last one, we return error.
>
> It's a little simpler than that. The return value is unconditionally
> cleared to 0 at the end so we always return success if the first
> nvme_identify() was successful. I wouldn't trust a controller that
> couldn't identify itself, but the remaining commands are for namespace
> identification which can legitimately return errors.

Ah correct, I missed that unconditional clear. I think it looks fine then.

-- 
Jens Axboe