RE: [PATCH 09/20] dlb2: add ioctl to configure ports, query poll mode

[Eads, Gage]

> -----Original Message-----
> From: Arnd Bergmann <arnd@xxxxxxxx>
> Sent: Sunday, July 12, 2020 10:34 AM
> To: Eads, Gage <gage.eads@xxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx; gregkh <gregkh@xxxxxxxxxxxxxxxxxxx>;
> Karlsson, Magnus <magnus.karlsson@xxxxxxxxx>; Topel, Bjorn
> <bjorn.topel@xxxxxxxxx>
> Subject: Re: [PATCH 09/20] dlb2: add ioctl to configure ports, query poll mode
> 
> On Sun, Jul 12, 2020 at 3:46 PM Gage Eads <gage.eads@xxxxxxxxx> wrote:
> >  enum dlb2_user_interface_commands {
> >         DLB2_CMD_GET_DEVICE_VERSION,
> >         DLB2_CMD_CREATE_SCHED_DOMAIN,
> >         DLB2_CMD_GET_SCHED_DOMAIN_FD,
> >         DLB2_CMD_GET_NUM_RESOURCES,
> >         DLB2_CMD_GET_DRIVER_VERSION,
> > +       DLB2_CMD_QUERY_CQ_POLL_MODE,
> >
> >         /* NUM_DLB2_CMD must be last */
> >         NUM_DLB2_CMD,
> 
> > @@ -427,6 +513,8 @@ struct dlb2_get_dir_queue_depth_args {  enum
> > dlb2_domain_user_interface_commands {
> >         DLB2_DOMAIN_CMD_CREATE_LDB_QUEUE,
> >         DLB2_DOMAIN_CMD_CREATE_DIR_QUEUE,
> > +       DLB2_DOMAIN_CMD_CREATE_LDB_PORT,
> > +       DLB2_DOMAIN_CMD_CREATE_DIR_PORT,
> >         DLB2_DOMAIN_CMD_GET_LDB_QUEUE_DEPTH,
> >         DLB2_DOMAIN_CMD_GET_DIR_QUEUE_DEPTH,
> 
> 
> You cannot add new commands in the middle without changing the ABI.
> 
> Maybe use individual #define lines in place of the enum to make sure these
> remain constants, or add a numeric value for each one when they are
> originally introduced.
> 
> (yes, I realize this is the initial contribution of the new driver, but it still seems
> wrong to have it change in the middle of the series).

Ok, no problem -- I was assuming this patchset would be considered an atomic unit. I'll correct this in V2.

Thanks,
Gage

> 
>       Arnd