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Message-Id: <20220705154932.2141021-9-ira.weiny@intel.com>
Date: Tue, 5 Jul 2022 08:49:31 -0700
From: ira.weiny@...el.com
To: Dan Williams <dan.j.williams@...el.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc: Ira Weiny <ira.weiny@...el.com>,
Ben Widawsky <bwidawsk@...nel.org>,
Alison Schofield <alison.schofield@...el.com>,
Lukas Wunner <lukas@...ner.de>,
Vishal Verma <vishal.l.verma@...el.com>,
Dave Jiang <dave.jiang@...el.com>,
linux-kernel@...r.kernel.org, linux-cxl@...r.kernel.org,
linux-pci@...r.kernel.org
Subject: [PATCH V13 8/9] cxl/port: Retry reading CDAT on failure
From: Ira Weiny <ira.weiny@...el.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 retry if the CDAT read
fails. For now 5 retries are implemented.
Reviewed-by: Ben Widawsky <bwidawsk@...nel.org>
Reviewed-by: Alison Schofield <alison.schofield@...el.com>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
Changes from V12
Jonathan:
Standardize on 'rc' for return code
Don't set rc unnecessarily
Changes from V10
Pick up review tag and fix commit message
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 | 39 +++++++++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 10 deletions(-)
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 0a1620c302e1..0853885c5767 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -623,13 +623,7 @@ static int cxl_cdat_read_table(struct device *dev,
return 0;
}
-/**
- * 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;
@@ -640,19 +634,19 @@ void read_cdat_data(struct cxl_port *port)
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;
rc = cxl_cdat_read_table(dev, cdat_mb, &port->cdat);
@@ -663,5 +657,30 @@ void read_cdat_data(struct cxl_port *port)
port->cdat.length = 0;
dev_err(dev, "CDAT data read error\n");
}
+
+ return rc;
+}
+
+/**
+ * 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);
--
2.35.3
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