On Mon, Jun 06, 2022 at 11:52:03AM -0700, Ben Widawsky wrote:
> On 22-06-04 17:50:48, ira.weiny@xxxxxxxxx wrote:
> > From: Ira Weiny <ira.weiny@xxxxxxxxx>
> >
> > The CDAT read may fail for a number of reasons but mainly it is possible
> > to get different parts of a valid state. The checksum in the CDAT table
> > protects against this.
> >
> > Now that the cdat data is validated issue a retries if the CDAT read
> s/validated issue a retries/validated, issue a retry/
Thanks!
> > fails. For now 5 retries are implemented.
> >
> > Cc: Alison Schofield <alison.schofield@xxxxxxxxx>
> > Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
> > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> >
> > ---
> > Changes from V9
> > Alison Schofield/Davidlohr Bueso
> > Print debug on each iteration and error only after failure
> >
> > Changes from V8
> > Move code to cxl/core/pci.c
> >
> > Changes from V6
> > Move to pci.c
> > Fix retries count
> > Change to 5 retries
> >
> > Changes from V5:
> > New patch -- easy to push off or drop.
> > ---
> > drivers/cxl/core/pci.c | 34 +++++++++++++++++++++++-----------
> > 1 file changed, 23 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
> > index 73e28b82ffcf..e68f13e66fcf 100644
> > --- a/drivers/cxl/core/pci.c
> > +++ b/drivers/cxl/core/pci.c
> > @@ -631,20 +631,18 @@ static int cxl_cdat_read_table(struct cxl_port *port,
> > return rc;
> > }
> >
> > -void read_cdat_data(struct cxl_port *port)
> > +static int __read_cdat_data(struct cxl_port *port)
> > {
> > struct device *dev = &port->dev;
> > size_t cdat_length;
> > int ret;
> >
> > if (cxl_cdat_get_length(port, &cdat_length))
> > - return;
> > + return 0;
> >
> > port->cdat.table = devm_kzalloc(dev, cdat_length, GFP_KERNEL);
> > - if (!port->cdat.table) {
> > - ret = -ENOMEM;
> > - goto error;
> > - }
> > + if (!port->cdat.table)
> > + return -ENOMEM;
> >
> > port->cdat.length = cdat_length;
> > ret = cxl_cdat_read_table(port, &port->cdat);
> > @@ -652,12 +650,26 @@ void read_cdat_data(struct cxl_port *port)
> > devm_kfree(dev, port->cdat.table);
> > port->cdat.table = NULL;
> > port->cdat.length = 0;
> > - ret = -EIO;
> > - goto error;
> > + return -EIO;
> > }
> >
> > - return;
> > -error:
> > - dev_err(dev, "CDAT data read error (%d)\n", ret);
> > + return 0;
> > +}
> > +
> > +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);
>
> Out of curiousity, what is the purpose of the dev_dbg? To diagnose delays or
> something?
Yes
>
> > + }
> > + dev_err(&port->dev, "CDAT data read failed after %d retries\n",
> > + retries);
>
>
> Reviewed-by: Ben Widawsky <bwidawsk@xxxxxxxxxx>
Thanks!
Ira
>
> > }
> > EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
> > --
> > 2.35.1
> >
