Re: [PATCH rdma-next v1 10/15] RDMA/cm: Use an attribute_group on the ib_port_attribute intead of kobj's

[Leon Romanovsky]

On Mon, Jun 07, 2021 at 12:25:03PM +0200, Greg KH wrote:
> On Mon, Jun 07, 2021 at 11:17:35AM +0300, Leon Romanovsky wrote:
> > From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> > 
> > This code is trying to attach a list of counters grouped into 4 groups to
> > the ib_port sysfs. Instead of creating a bunch of kobjects simply express
> > everything naturally as an ib_port_attribute and add a single
> > attribute_groups list.
> > 
> > Remove all the naked kobject manipulations.
> 
> Much nicer.
> 
> But why do you need your counters to be atomic in the first place?  What
> are they counting that requires this?  Given that they are just a
> statistic for userspace, making them be a u64 should work just the same,
> right?

The statistic counters are per-port, while the cm.c flows run in
asynchronically in parallel for every CM connection.

We need atomic variable to ensure that "write to u64" is not
interrupted.

Thanks