linux-kernel - [RFC PATCH 2/9] PCI/AER: Call AER CE handler before clearing AER CE status register

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Date: Mon, 17 Jun 2024 15:04:04 -0500
From: Terry Bowman <terry.bowman@....com>
To: <dan.j.williams@...el.com>, <ira.weiny@...el.com>, <dave@...olabs.net>,
	<dave.jiang@...el.com>, <alison.schofield@...el.com>, <ming4.li@...el.com>,
	<vishal.l.verma@...el.com>, <jim.harris@...sung.com>,
	<ilpo.jarvinen@...ux.intel.com>, <ardb@...nel.org>,
	<sathyanarayanan.kuppuswamy@...ux.intel.com>, <linux-cxl@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <terry.bowman@....com>,
	<Yazen.Ghannam@....com>, <Robert.Richter@....com>
CC: Bjorn Helgaas <bhelgaas@...gle.com>, <linux-pci@...r.kernel.org>
Subject: [RFC PATCH 2/9] PCI/AER: Call AER CE handler before clearing AER CE status register

The AER service driver clears the AER correctable error (CE) status before
calling the correctable error handler. This results in the error's status
not correctly reflected if read from the CE handler.

The AER CE status is needed by the portdrv's CE handler. The portdrv's
CE handler is intended to only call the registered notifier callbacks
if the CE error status has correctable internal error (CIE) set.

This is not a problem for AER uncorrrectbale errors (UCE). The UCE status
is still present in the AER capability and available for reading, if
needed, when the UCE handler is called.

Change the order of clearing the CE status and calling the CE handler.
Make it to call the CE handler first and then clear the CE status
after returning.

Signed-off-by: Terry Bowman <terry.bowman@....com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: linux-pci@...r.kernel.org
---
 drivers/pci/pcie/aer.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index ac6293c24976..4dc03cb9aff0 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1094,9 +1094,6 @@ static void pci_aer_handle_error(struct pci_dev *dev, struct aer_err_info *info)
 		 * Correctable error does not need software intervention.
 		 * No need to go through error recovery process.
 		 */
-		if (aer)
-			pci_write_config_dword(dev, aer + PCI_ERR_COR_STATUS,
-					info->status);
 		if (pcie_aer_is_native(dev)) {
 			struct pci_driver *pdrv = dev->driver;
 
@@ -1105,6 +1102,10 @@ static void pci_aer_handle_error(struct pci_dev *dev, struct aer_err_info *info)
 				pdrv->err_handler->cor_error_detected(dev);
 			pcie_clear_device_status(dev);
 		}
+		if (aer)
+			pci_write_config_dword(dev, aer + PCI_ERR_COR_STATUS,
+					info->status);
+
 	} else if (info->severity == AER_NONFATAL)
 		pcie_do_recovery(dev, pci_channel_io_normal, aer_root_reset);
 	else if (info->severity == AER_FATAL)
-- 
2.34.1