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

[Anuj Gupta]

On Tue, Nov 12, 2024 at 12:54:23AM +0000, Pavel Begunkov wrote:
> On 11/7/24 07:26, Anuj gupta wrote:
> > On Thu, Nov 7, 2024 at 11:25 AM Christoph Hellwig <hch at 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.

In next version, I can move it to the beginning of second SQE.

ext_cap also keeps it open to pass the same/different attributes via
user pointer.
Is that fine, or do you want anything else to be changed?

> 
> -- 
> Pavel Begunkov
>