Re: [PATCH 00/13] Reorganize sysfs file creation for struct ib_devices

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, May 18, 2021 at 04:07:49PM -0700, Nathan Chancellor wrote:
> Hi Jason,
> 
> On 5/17/2021 9:47 AM, Jason Gunthorpe wrote:
> > IB has a complex sysfs with a deep nesting of attributes. Nathan and Kees
> > recently noticed this was not even slightly sane with how it was handling
> > attributes and a deeper inspection shows the whole thing is a pretty
> > "ick" coding style.
> > 
> > Further review shows the ick extends outward from the ib_port sysfs and
> > basically everything is pretty crazy.
> > 
> > Simplify all of it:
> > 
> >   - Organize the ib_port and gid_attr's kobj's to have clear setup/destroy
> >     function pairings that work only on their own kobjs.
> > 
> >   - All memory allocated in service of a kobject's attributes is freed as
> >     part of the kobj release function. Thus all the error handling defers
> >     the memory frees to a put.
> > 
> >   - Build up lists of groups for every kobject and add the entire group
> >     list as a one-shot operation as the last thing in setup function.
> > 
> >   - Remove essentially all the error cleanup. The final kobject_put() will
> >     always free any memory allocated or do an internal kobject_del() if
> >     required. The new ordering eliminates all the other cleanup cases.
> > 
> >   - Make all attributes use proper typing for the kobj they are attached
> >     to. Split device and port hw_stats handling.
> > 
> >   - Create a ib_port_attribute type and change hfi1, qib and the CM code to
> >     work with attribute lists of ib_port_attribute type instead of building
> >     their own kobject madness
> > 
> > This is sort of RFCy in that I qib and hfi1 stuff is complex enough it needs
> > Dennis to look at it, and the core stuff has only passed basic testing at this
> > moment. Nathan confirmed an earlier version solves the CFI warning.
> 
> This series still passes my basic testing of LTP's read_all test case on
> /sys with CFI in enforcing mode. If there is any more in-depth testing, I
> can put it through, let me know. I'll continue testing the series and when
> it is in a mergeable state, I can provide you with a Tested-by tag.

Thanks, I think you can probably ignore the following versions,
confirmation that the approach and root cause is correct is much
appreciated.

Jason