Re: [PATCH] io_uring: Add io_uring command support for sockets

Breno Leitao
2023-06-22T16:39:05Z

On Thu, Jun 22, 2023 at 06:10:00PM +0200, Greg Kroah-Hartman wrote:
> On Thu, Jun 22, 2023 at 08:02:37AM -0700, Breno Leitao wrote:
> > On Thu, Jun 22, 2023 at 07:20:48AM +0200, Greg Kroah-Hartman wrote:
> > > On Wed, Jun 21, 2023 at 04:21:26PM -0700, Breno Leitao wrote:
> > > > --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> > > > +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> > > > @@ -361,6 +361,7 @@ Code Seq# Include File Comments
> > > > 0xCB 00-1F CBM serial IEC bus in development:
> > > > <mailto:michael.klein@puffin.lb.shuttle.de>
> > > > 0xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver
> > > > +0xCC A0-BF uapi/linux/io_uring.h io_uring cmd subsystem
> > >
> > > This change is nice, but not totally related to this specific one,
> > > shouldn't it be separate?
> >
> > This is related to this patch, since I am using it below, in the
> > following part:
> >
> > +#define SOCKET_URING_OP_SIOCINQ _IOR(0xcc, 0xa0, int)
> > +#define SOCKET_URING_OP_SIOCOUTQ _IOR(0xcc, 0xa1, int)
> >
> > Should I have a different patch, even if they are related?
>
> Yes, as you are not using the 0xa2-0xbf range that you just carved out
> here, right? Where did those numbers come from?

Correct. For now we are just using 0xa0 and 0xa1, and eventually we
might need more ioctls numbers.

I got these numbers finding a unused block and having some room for
expansion, as suggested by Documentation/userspace-api/ioctl/ioctl-number.rst,
that says:

If you are writing a driver for a new device and need a letter, pick an
unused block with enough room for expansion: 32 to 256 ioctl commands.