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SubjectRe: [PATCH V10 8/9] cxl/port: Retry reading CDAT on failure
On 22-06-04 17:50:48, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
>
> 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/
> fails. For now 5 retries are implemented.
>
> Cc: Alison Schofield <alison.schofield@intel.com>
> Cc: Davidlohr Bueso <dave@stgolabs.net>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
>
> ---
> 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?

> + }
> + dev_err(&port->dev, "CDAT data read failed after %d retries\n",
> + retries);


Reviewed-by: Ben Widawsky <bwidawsk@kernel.org>

> }
> EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
> --
> 2.35.1
>

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