can: peak/pci: fix potential bug when probe() fails

PCI/PCIe drivers for PEAK-System CAN/CAN-FD interfaces do some access to the
PCI config during probing. In case one of these accesses fails, a POSITIVE
PCIBIOS_xxx error code is returned back. This POSITIVE error code MUST be
converted into a NEGATIVE errno for the probe() function to indicate it
failed. Using the pcibios_err_to_errno() function, we make sure that the
return code will always be negative.

Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/peak_canfd/peak_pciefd_main.c

@@ -825,7 +825,10 @@ err_release_regions:
 err_disable_pci:
 	pci_disable_device(pdev);
 
-	return err;
+	/* pci_xxx_config_word() return positive PCIBIOS_xxx error codes while
+	 * the probe() function must return a negative errno in case of failure
+	 * (err is unchanged if negative) */
+	return pcibios_err_to_errno(err);
 }
 
 /* free the board structure object, as well as its resources: */

drivers/net/can/sja1000/peak_pci.c

@@ -717,7 +717,10 @@ failure_release_regions:
 failure_disable_pci:
 	pci_disable_device(pdev);
 
-	return err;
+	/* pci_xxx_config_word() return positive PCIBIOS_xxx error codes while
+	 * the probe() function must return a negative errno in case of failure
+	 * (err is unchanged if negative) */
+	return pcibios_err_to_errno(err);
 }
 
 static void peak_pci_remove(struct pci_dev *pdev)