Re: [PATCHv5 07/11] io_uring: add support for kernel registered bvecs

[Ming Lei <ming.lei@redhat.com>]

On Wed, Feb 26, 2025 at 1:32 AM Keith Busch <kbusch@kernel.org> wrote:
>
> On Tue, Feb 25, 2025 at 05:40:14PM +0800, Ming Lei wrote:
> > On Mon, Feb 24, 2025 at 01:31:12PM -0800, Keith Busch wrote:
> > > +
> > > +   if (op_is_write(req_op(rq)))
> > > +           imu->perm = IO_IMU_WRITEABLE;
> > > +   else
> > > +           imu->perm = IO_IMU_READABLE;
> >
> > Looks the above is wrong, if request is for write op, the buffer
> > should be readable & !writeable.
> >
> > IO_IMU_WRITEABLE is supposed to mean the buffer is writeable, isn't it?
>
> In the setup I used here, IMU_WRITEABLE means this can be used in a
> write command. You can write from this buffer, not to it.

But IMU represents a buffer, and the buffer could be used for other
OPs in future,
instead of write command only. Here it is more readable to mark the buffer
readable or writable.

I'd suggest not introducing the confusion from the beginning.

Thanks,