On Mon, 29 Jul 2024 13:35:13 -0300 Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > On Fri, Jul 26, 2024 at 04:15:03PM +0100, Jonathan Cameron wrote: > > On Mon, 24 Jun 2024 19:47:27 -0300 > > Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > > > > > Userspace will need to know some details about the fwctl interface being > > > used to locate the correct userspace code to communicate with the > > > kernel. Provide a simple device_type enum indicating what the kernel > > > driver is. > > > > As below - maybe consider a UUID? > > Would let you decouple allocating those with upstreaming drivers. > > We'll just get annoying races on the enum otherwise as multiple > > drivers get upstreamed that use this. > > I view the coupling as a feature - controlling uABI number assignment > is one of the subtle motivations the kernel community has typically > used to encourage upstream participation. Hmm. I'm not sure it's worth the possible pain if this becomes popular. Maybe you'll have to run a reservation hotline. > > > > +/** > > > + * struct fwctl_info - ioctl(FWCTL_INFO) > > > + * @size: sizeof(struct fwctl_info) > > > + * @flags: Must be 0 > > > + * @out_device_type: Returns the type of the device from enum fwctl_device_type > > > > Maybe a UUID? Avoid need to synchronize that list for ever. > > > > > + * @device_data_len: On input the length of the out_device_data memory. On > > > + * output the size of the kernel's device_data which may be larger or > > > + * smaller than the input. Maybe 0 on input. > > > + * @out_device_data: Pointer to a memory of device_data_len bytes. Kernel will > > > + * fill the entire memory, zeroing as required. > > > > Why do we need device in names of these two? > > I'm not sure I understand this question? > > out_device_type returns the "name" > > out_device_data returns a struct of data, the layout of the struct is > defined by out_device_type What is device in this case? fwctl struct device, hardware device, something else? I'm not sure what the names give over fwctl_type, out_data_len, out_data The first one can't just be type as likely as not out_data contains a type field specific to the fwctl_device_type. I don't feel that strongly about this though, so stick to device if you like. I'll get used to it. Jonathan > > Jason
