On 11/12/24 5:54 AM, Shuai Xue wrote:
The current implementation of pcie_do_recovery() assumes that the
recovery process is executed on the device that detected the error.
However, the DPC driver currently passes the error port that experienced
the DPC event to pcie_do_recovery().

Use the SOURCE ID register to correctly identify the device that detected the
error. By passing this error device to pcie_do_recovery(), subsequent
patches will be able to accurately access AER status of the error device.

When passing the error device, I assume pcie_do_recovery() will find the
upstream bride and run the recovery logic .


Signed-off-by: Shuai Xue <xuesh...@linux.alibaba.com>
---

IMO, moving the "err_port" rename to a separate patch will make this change
more clear.  But it is up to you.

  drivers/pci/pci.h      |  2 +-
  drivers/pci/pcie/dpc.c | 30 ++++++++++++++++++++++++------
  drivers/pci/pcie/edr.c | 35 ++++++++++++++++++-----------------
  3 files changed, 43 insertions(+), 24 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 14d00ce45bfa..0866f79aec54 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -521,7 +521,7 @@ struct rcec_ea {
  void pci_save_dpc_state(struct pci_dev *dev);
  void pci_restore_dpc_state(struct pci_dev *dev);
  void pci_dpc_init(struct pci_dev *pdev);
-void dpc_process_error(struct pci_dev *pdev);
+struct pci_dev *dpc_process_error(struct pci_dev *pdev);
  pci_ers_result_t dpc_reset_link(struct pci_dev *pdev);
  bool pci_dpc_recovered(struct pci_dev *pdev);
  #else
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 2b6ef7efa3c1..62a68cde4364 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -257,10 +257,17 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev 
*dev,
        return 1;
  }
-void dpc_process_error(struct pci_dev *pdev)
+/**
+ * dpc_process_error - handle the DPC error status

Handling the DPC error status has nothing to do with finding
the error source. Why not add a new helper function?

+ * @pdev: the port that experienced the containment event
+ *
+ * Return the device that experienced the error.
detected the error?
+ */
+struct pci_dev *dpc_process_error(struct pci_dev *pdev)
  {
        u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
        struct aer_err_info info;
+       struct pci_dev *err_dev = NULL;

I don't think you need NULL initialization here.

pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
        pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
@@ -283,6 +290,13 @@ void dpc_process_error(struct pci_dev *pdev)
                 "software trigger" :
                 "reserved error");
+ if (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE ||
+           reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE)
+               err_dev = pci_get_domain_bus_and_slot(pci_domain_nr(pdev->bus),
+                                           PCI_BUS_NUM(source), source & 0xff);
+       else
+               err_dev = pci_dev_get(pdev);
+
        /* show RP PIO error detail information */
        if (pdev->dpc_rp_extensions &&
            reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT &&
@@ -295,6 +309,8 @@ void dpc_process_error(struct pci_dev *pdev)
                pci_aer_clear_nonfatal_status(pdev);
                pci_aer_clear_fatal_status(pdev);
        }
+
+       return err_dev;
  }
static void pci_clear_surpdn_errors(struct pci_dev *pdev)
@@ -350,21 +366,23 @@ static bool dpc_is_surprise_removal(struct pci_dev *pdev)
static irqreturn_t dpc_handler(int irq, void *context)
  {
-       struct pci_dev *pdev = context;
+       struct pci_dev *err_port = context, *err_dev = NULL;

NULL initialization is not needed.

/*
         * According to PCIe r6.0 sec 6.7.6, errors are an expected side effect
         * of async removal and should be ignored by software.
         */
-       if (dpc_is_surprise_removal(pdev)) {
-               dpc_handle_surprise_removal(pdev);
+       if (dpc_is_surprise_removal(err_port)) {
+               dpc_handle_surprise_removal(err_port);
                return IRQ_HANDLED;
        }
- dpc_process_error(pdev);
+       err_dev = dpc_process_error(err_port);
/* We configure DPC so it only triggers on ERR_FATAL */
-       pcie_do_recovery(pdev, pci_channel_io_frozen, dpc_reset_link);
+       pcie_do_recovery(err_dev, pci_channel_io_frozen, dpc_reset_link);
+
+       pci_dev_put(err_dev);
return IRQ_HANDLED;
  }
diff --git a/drivers/pci/pcie/edr.c b/drivers/pci/pcie/edr.c
index e86298dbbcff..6ac95e5e001b 100644
--- a/drivers/pci/pcie/edr.c
+++ b/drivers/pci/pcie/edr.c
@@ -150,7 +150,7 @@ static int acpi_send_edr_status(struct pci_dev *pdev, 
struct pci_dev *edev,
static void edr_handle_event(acpi_handle handle, u32 event, void *data)
  {
-       struct pci_dev *pdev = data, *edev;
+       struct pci_dev *pdev = data, *err_port, *err_dev = NULL;
        pci_ers_result_t estate = PCI_ERS_RESULT_DISCONNECT;
        u16 status;
@@ -169,36 +169,36 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
         * may be that port or a parent of it (PCI Firmware r3.3, sec
         * 4.6.13).
         */
-       edev = acpi_dpc_port_get(pdev);
-       if (!edev) {
+       err_port = acpi_dpc_port_get(pdev);
+       if (!err_port) {
                pci_err(pdev, "Firmware failed to locate DPC port\n");
                return;
        }
- pci_dbg(pdev, "Reported EDR dev: %s\n", pci_name(edev));
+       pci_dbg(pdev, "Reported EDR dev: %s\n", pci_name(err_port));
/* If port does not support DPC, just send the OST */
-       if (!edev->dpc_cap) {
-               pci_err(edev, FW_BUG "This device doesn't support DPC\n");
+       if (!err_port->dpc_cap) {
+               pci_err(err_port, FW_BUG "This device doesn't support DPC\n");
                goto send_ost;
        }
/* Check if there is a valid DPC trigger */
-       pci_read_config_word(edev, edev->dpc_cap + PCI_EXP_DPC_STATUS, &status);
+       pci_read_config_word(err_port, err_port->dpc_cap + PCI_EXP_DPC_STATUS, 
&status);
        if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) {
-               pci_err(edev, "Invalid DPC trigger %#010x\n", status);
+               pci_err(err_port, "Invalid DPC trigger %#010x\n", status);
                goto send_ost;
        }
- dpc_process_error(edev);
-       pci_aer_raw_clear_status(edev);
+       err_dev = dpc_process_error(err_port);
+       pci_aer_raw_clear_status(err_port);
/*
         * Irrespective of whether the DPC event is triggered by ERR_FATAL
         * or ERR_NONFATAL, since the link is already down, use the FATAL
         * error recovery path for both cases.
         */
-       estate = pcie_do_recovery(edev, pci_channel_io_frozen, dpc_reset_link);
+       estate = pcie_do_recovery(err_dev, pci_channel_io_frozen, 
dpc_reset_link);
send_ost: @@ -207,15 +207,16 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)
         * to firmware. If not successful, send _OST(0xF, BDF << 16 | 0x81).
         */
        if (estate == PCI_ERS_RESULT_RECOVERED) {
-               pci_dbg(edev, "DPC port successfully recovered\n");
-               pcie_clear_device_status(edev);
-               acpi_send_edr_status(pdev, edev, EDR_OST_SUCCESS);
+               pci_dbg(err_port, "DPC port successfully recovered\n");
+               pcie_clear_device_status(err_port);
+               acpi_send_edr_status(pdev, err_port, EDR_OST_SUCCESS);
        } else {
-               pci_dbg(edev, "DPC port recovery failed\n");
-               acpi_send_edr_status(pdev, edev, EDR_OST_FAILED);
+               pci_dbg(err_port, "DPC port recovery failed\n");
+               acpi_send_edr_status(pdev, err_port, EDR_OST_FAILED);
        }
- pci_dev_put(edev);
+       pci_dev_put(err_port);
+       pci_dev_put(err_dev);
  }
void pci_acpi_add_edr_notifier(struct pci_dev *pdev)

--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer


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