Re: [Qemu-devel] [PATCH 2/2] block/nvme: add support for discard

[John Snow <jsnow@redhat.com>]

On 9/5/19 9:24 AM, Maxim Levitsky wrote:
> On Wed, 2019-08-28 at 12:03 +0300, Maxim Levitsky wrote:
>> On Tue, 2019-08-27 at 18:29 -0400, John Snow wrote:
>>>
>>> On 8/25/19 3:15 AM, Maxim Levitsky wrote:
>>>> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
>>>> ---
>>>>  block/nvme.c       | 83 ++++++++++++++++++++++++++++++++++++++++++++++
>>>>  block/trace-events |  2 ++
>>>>  2 files changed, 85 insertions(+)
>>>>
>>>> diff --git a/block/nvme.c b/block/nvme.c
>>>> index f8bd11e19a..dd041f39c9 100644
>>>> --- a/block/nvme.c
>>>> +++ b/block/nvme.c
>>>> @@ -112,6 +112,7 @@ typedef struct {
>>>>      bool plugged;
>>>>  
>>>>      bool supports_write_zeros;
>>>> +    bool supports_discard;
>>>>  
>>>>      CoMutex dma_map_lock;
>>>>      CoQueue dma_flush_queue;
>>>> @@ -463,6 +464,7 @@ static void nvme_identify(BlockDriverState *bs, int namespace, Error **errp)
>>>>  
>>>>      oncs = le16_to_cpu(idctrl->oncs);
>>>>      s->supports_write_zeros = (oncs & NVME_ONCS_WRITE_ZEROS) != 0;
>>>> +    s->supports_discard = (oncs & NVME_ONCS_DSM) != 0;
>>>
>>> Same comment -- checking !!(register & FIELD) is nicer than the
>>> negative. (I'm actually not sure even the !! is needed, but it seems to
>>> be a QEMU-ism and I've caught myself using it...)
>>
>> All right, no problem to use !!
>>
>>>
>>> Rest looks good to me on a skim, but I'm not very well-versed in NVME.
>>
>> Thanks!
>>
> 
> Kind ping about this patch series.
> 
> Apart from using !!, do you think that this patch series
> can be merged, or should I do anything else?
> Which tree do you think this should be committed to?
> 
> I kind of want to see that merged before the freeze
> starts, if there are no objections,
> to reduce the amount of pending stuff in my queue.
> 

Didn't I ask a few other things?

like not using "res30" because you've moved the fields around, and
trying to be consistent about "zeros" vs "zeroes".

Removing "+#define NVME_ID_NS_DLFEAT_GUARD_CRC(dlfeat)       ((dlfeat) &
0x10)" because it's unused.

You also probably require review (or at least an ACK) from Keith Busch
who maintains this file.

--js