Re: [PATCH V12 8/9] cxl/port: Retry reading CDAT on failure

Ira Weiny
2022-06-30T03:40:43Z

On Tue, Jun 28, 2022 at 03:57:20PM +0100, Jonathan Cameron wrote:
> On Mon, 27 Jun 2022 21:15:26 -0700
> ira.weiny@intel.com wrote:
>

[snip]

> >
> > -/**
> > - * read_cdat_data - Read the CDAT data on this port
> > - * @port: Port to read data from
> > - *
> > - * This call will sleep waiting for responses from the DOE mailbox.
> > - */
> > -void read_cdat_data(struct cxl_port *port)
> > +static int __read_cdat_data(struct cxl_port *port)
> > {
> > static struct pci_doe_mb *cdat_mb;
> > struct device *dev = &port->dev;
> > struct device *uport = port->uport;
> > size_t cdat_length;
> > - int ret;
> > + int ret = 0;
> Fairly sure there isn't a path in which ret isn't set...
>

Yep.

>
> Mixing ret and rc is a bit inconsistent, maybe scrub patch set for
> one or the other. (My fault originally I think :)

Ok PCI uses both ret and rc. :-( But CXL seems to be consistent with rc. So
I've used rc with the new series which I think satisfies both subsystems.

Thanks again for the detail review of the series. Hopefully there will be a
new version out tomorrow.
Ira

>
>
> >
> > cdat_mb = find_cdat_mb(uport);
> > if (!cdat_mb) {
> > dev_dbg(dev, "No CDAT mailbox\n");
> > - return;
> > + return -EIO;
> > }
> >
> > port->cdat_sup = true;
> >
> > if (cxl_cdat_get_length(dev, cdat_mb, &cdat_length)) {
> > dev_dbg(dev, "No CDAT length\n");
> > - return;
> > + return -EIO;
> > }
> >
> > port->cdat.table = devm_kzalloc(dev, cdat_length, GFP_KERNEL);
> > if (!port->cdat.table)
> > - return;
> > + return -ENOMEM;
> >
> > port->cdat.length = cdat_length;
> > ret = cxl_cdat_read_table(dev, cdat_mb, &port->cdat);
> > @@ -658,5 +652,30 @@ void read_cdat_data(struct cxl_port *port)
> > port->cdat.length = 0;
> > dev_err(dev, "CDAT data read error\n");
> > }
> > +
> > + return ret;
> > +}
> > +
> > +/**
> > + * read_cdat_data - Read the CDAT data on this port
> > + * @port: Port to read data from
> > + *
> > + * This call will sleep waiting for responses from the DOE mailbox.
> > + */
> > +void read_cdat_data(struct cxl_port *port)
> > +{
> > + int retries = 5;
> > + int rc;
> > +
> > + while (retries--) {
> > + rc = __read_cdat_data(port);
> > + if (!rc)
> > + return;
> > + dev_dbg(&port->dev,
> > + "CDAT data read error rc=%d (retries %d)\n",
> > + rc, retries);
> > + }
> > + dev_err(&port->dev, "CDAT data read failed after %d retries\n",
> > + retries);
> > }
> > EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
>