Re: [PATCH v8 06/10] io_uring/rw: add support to send metadata along with read/write

[Pavel Begunkov <asml.silence@gmail.com>]

On 11/7/24 07:26, Anuj gupta wrote:
> On Thu, Nov 7, 2024 at 11:25 AM Christoph Hellwig <hch@lst.de> wrote:
...
>>
>> struct io_uring_sqe_ext {
>>          /*
>>           * Reservered for please tell me what and why it is in the beginning
>>           * and not the end:
>>           */
>>          __u64   rsvd0[4];
> 
> This space is reserved for extended capabilities that might be added down
> the line. It was at the end in the earlier versions, but it is moved
> to the beginning
> now to maintain contiguity with the free space (18b) available in the first SQE,
> based on previous discussions [1].
> 
> [1] https://lore.kernel.org/linux-block/ceb58d97-b2e3-4d36-898d-753ba69476be@samsung.com/

I don't believe it helps much anything, placing a structure on the
border between SQEs also feels a bit odd.

-- 
Pavel Begunkov