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From: Sean V Kelley <seanvk.dev@oregontracks.org>
To: bhelgaas@google.com, Jonathan.Cameron@huawei.com,
	rafael.j.wysocki@intel.com, ashok.raj@intel.com,
	tony.luck@intel.com, sathyanarayanan.kuppuswamy@intel.com,
	qiuxu.zhuo@intel.com
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	Sean V Kelley <sean.v.kelley@intel.com>
Subject: [PATCH v9 10/15] PCI/ERR: Limit AER resets in pcie_do_recovery()
Date: Thu, 15 Oct 2020 17:11:08 -0700
Message-ID: <20201016001113.2301761-11-seanvk.dev@oregontracks.org> (raw)
In-Reply-To: <20201016001113.2301761-1-seanvk.dev@oregontracks.org>

From: Sean V Kelley <sean.v.kelley@intel.com>

In some cases a bridge may not exist as the hardware controlling may be
handled only by firmware and so is not visible to the OS. This scenario is
also possible in future use cases involving non-native use of RCECs by
firmware.

Explicitly apply conditional logic around these resets by limiting them to
Root Ports and Downstream Ports.

Link: https://lore.kernel.org/r/20201002184735.1229220-8-seanvk.dev@oregontracks.org
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/pci/pcie/err.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 8b53aecdb43d..7883c9791562 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -148,13 +148,17 @@ static int report_resume(struct pci_dev *dev, void *data)
 
 /**
  * pci_walk_bridge - walk bridges potentially AER affected
- * @bridge:	bridge which may be a Port
+ * @bridge:	bridge which may be a Port, an RCEC with associated RCiEPs,
+ *		or an RCiEP associated with an RCEC
  * @cb:		callback to be called for each device found
  * @userdata:	arbitrary pointer to be passed to callback
  *
  * If the device provided is a bridge, walk the subordinate bus, including
  * any bridged devices on buses under this bus.  Call the provided callback
  * on each device found.
+ *
+ * If the device provided has no subordinate bus, call the callback on the
+ * device itself.
  */
 static void pci_walk_bridge(struct pci_dev *bridge,
 			    int (*cb)(struct pci_dev *, void *),
@@ -162,6 +166,8 @@ static void pci_walk_bridge(struct pci_dev *bridge,
 {
 	if (bridge->subordinate)
 		pci_walk_bus(bridge->subordinate, cb, userdata);
+	else
+		cb(bridge, userdata);
 }
 
 pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
@@ -174,10 +180,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 
 	/*
 	 * Error recovery runs on all subordinates of the bridge.  If the
-	 * bridge detected the error, it is cleared at the end.
+	 * bridge detected the error, it is cleared at the end.  For RCiEPs
+	 * we should reset just the RCiEP itself.
 	 */
 	if (type == PCI_EXP_TYPE_ROOT_PORT ||
-	    type == PCI_EXP_TYPE_DOWNSTREAM)
+	    type == PCI_EXP_TYPE_DOWNSTREAM ||
+	    type == PCI_EXP_TYPE_RC_EC ||
+	    type == PCI_EXP_TYPE_RC_END)
 		bridge = dev;
 	else
 		bridge = pci_upstream_bridge(dev);
@@ -185,6 +194,12 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	pci_dbg(bridge, "broadcast error_detected message\n");
 	if (state == pci_channel_io_frozen) {
 		pci_walk_bridge(bridge, report_frozen_detected, &status);
+		if (type == PCI_EXP_TYPE_RC_END) {
+			pci_warn(dev, "subordinate device reset not possible for RCiEP\n");
+			status = PCI_ERS_RESULT_NONE;
+			goto failed;
+		}
+
 		status = reset_subordinates(bridge);
 		if (status != PCI_ERS_RESULT_RECOVERED) {
 			pci_warn(bridge, "subordinate device reset failed\n");
@@ -217,9 +232,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	pci_dbg(bridge, "broadcast resume message\n");
 	pci_walk_bridge(bridge, report_resume, &status);
 
-	if (pcie_aer_is_native(bridge))
-		pcie_clear_device_status(bridge);
-	pci_aer_clear_nonfatal_status(bridge);
+	if (type == PCI_EXP_TYPE_ROOT_PORT ||
+	    type == PCI_EXP_TYPE_DOWNSTREAM ||
+	    type == PCI_EXP_TYPE_RC_EC) {
+		if (pcie_aer_is_native(bridge))
+			pcie_clear_device_status(bridge);
+		pci_aer_clear_nonfatal_status(bridge);
+	}
 	pci_info(bridge, "device recovery successful\n");
 	return status;
 
-- 
2.28.0


  parent reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-16  0:10 [PATCH v9 00/15] Add RCEC handling to PCI/AER Sean V Kelley
2020-10-16  0:10 ` [PATCH v9 01/15] PCI/RCEC: Add RCEC class code and extended capability Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 02/15] PCI/RCEC: Bind RCEC devices to the Root Port driver Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 03/15] PCI/RCEC: Cache RCEC capabilities in pci_init_capabilities() Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 04/15] PCI/ERR: Rename reset_link() to reset_subordinates() Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 05/15] PCI/ERR: Simplify by using pci_upstream_bridge() Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 06/15] PCI/ERR: Simplify by computing pci_pcie_type() once Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 07/15] PCI/ERR: Use "bridge" for clarity in pcie_do_recovery() Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 08/15] PCI/ERR: Avoid negated conditional for clarity Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 09/15] PCI/ERR: Add pci_walk_bridge() to pcie_do_recovery() Sean V Kelley
2020-10-16 17:19   ` Bjorn Helgaas
2020-10-16  0:11 ` Sean V Kelley [this message]
2020-10-16 17:22   ` [PATCH v9 10/15] PCI/ERR: Limit AER resets in pcie_do_recovery() Bjorn Helgaas
2020-10-16 17:36     ` Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 11/15] PCI/RCEC: Add pcie_link_rcec() to associate RCiEPs Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 12/15] PCI/RCEC: Add RCiEP's linked RCEC to AER/ERR Sean V Kelley
2020-10-16 20:30   ` Bjorn Helgaas
2020-10-16 22:29     ` Bjorn Helgaas
2020-10-17  0:28       ` Kuppuswamy, Sathyanarayanan
2020-10-17  1:45       ` Kuppuswamy, Sathyanarayanan
2020-10-19 10:49       ` Ethan Zhao
2020-10-19 18:31         ` Sean V Kelley
2020-10-19 18:59           ` Kuppuswamy, Sathyanarayanan
2020-10-19 20:50             ` Sean V Kelley
2020-10-20 12:59               ` Jonathan Cameron
2020-10-20 16:28                 ` Bjorn Helgaas
2020-10-17 16:14     ` Sean V Kelley
2020-10-19 19:07       ` Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 13/15] PCI/AER: Add pcie_walk_rcec() to RCEC AER handling Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 14/15] PCI/PME: Add pcie_walk_rcec() to RCEC PME handling Sean V Kelley
2020-10-16  0:11 ` [PATCH v9 15/15] PCI/AER: Add RCEC AER error injection support Sean V Kelley

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