[dm-devel] [PATCH 1/9] QUEUE_FLAG_NOWAIT to indicate device supports nowait

[Jens Axboe]

On 08/10/2017 05:38 AM, Goldwyn Rodrigues wrote:
> 
> 
> On 08/09/2017 09:18 PM, Jens Axboe wrote:
>> On 08/08/2017 02:36 PM, Jens Axboe wrote:
>>> On 08/08/2017 02:32 PM, Shaohua Li wrote:
>>>>> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
>>>>> index 25f6a0cb27d3..fae021ebec1b 100644
>>>>> --- a/include/linux/blkdev.h
>>>>> +++ b/include/linux/blkdev.h
>>>>> @@ -633,6 +633,7 @@ struct request_queue {
>>>>>  #define QUEUE_FLAG_REGISTERED  29	/* queue has been registered to a disk */
>>>>>  #define QUEUE_FLAG_SCSI_PASSTHROUGH 30	/* queue supports SCSI commands */
>>>>>  #define QUEUE_FLAG_QUIESCED    31	/* queue has been quiesced */
>>>>> +#define QUEUE_FLAG_NOWAIT      32	/* stack device driver supports REQ_NOWAIT */
>>>
>>> Does this work on 32-bit, where sizeof(unsigned long) == 32?
>>
>> I didn't get an answer to this one.
>>
> 
> Oh, I assumed the question is rhetorical.
> No, it will not work on 32-bit. I was planning to change the field
> queue_flags to u64. Is that okay?

No, besides that would not work with set/test_bit() and friends. Grab
a free bit instead.

-- 
Jens Axboe