DPC: Run recovery on device that detected the error

Shuai Xue Wed, 18 Jun 2025 23:29:05 -0700



在 2025/6/12 18:31, Manivannan Sadhasivam 写道:

On Mon, Feb 17, 2025 at 10:42:17AM +0800, Shuai Xue wrote:

The current implementation of pcie_do_recovery() assumes that the
recovery process is executed on the device that detected the error.


s/on/for

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. When passing the error device, the
pcie_do_recovery() will find the upstream bridge and walk bridges
potentially AER affected. And subsequent patches will be able to


s/patches/commits


Will fix the typos.

accurately access AER status of the error device.

Should not observe any functional changes.

Signed-off-by: Shuai Xue <xuesh...@linux.alibaba.com>
---
  drivers/pci/pci.h      |  2 +-
  drivers/pci/pcie/dpc.c | 28 ++++++++++++++++++++++++----
  drivers/pci/pcie/edr.c |  7 ++++---
  3 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 01e51db8d285..870d2fbd6ff2 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -572,7 +572,7 @@ 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);
  unsigned int dpc_tlp_log_len(struct pci_dev *dev);
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 1a54a0b657ae..ea3ea989afa7 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -253,10 +253,20 @@ 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
+ * @pdev: the port that experienced the containment event
+ *
+ * Return the device that detected the error.


s/Return/Return:

+ *
+ * NOTE: The device reference count is increased, the caller must decrement
+ * the reference count by calling pci_dev_put().
+ */
+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;

pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);

        pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
@@ -279,6 +289,13 @@ 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 &&
@@ -291,6 +308,8 @@ 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)

@@ -346,7 +365,7 @@ static bool dpc_is_surprise_removal(struct pci_dev *pdev)

static irqreturn_t dpc_handler(int irq, void *context)

  {
-       struct pci_dev *err_port = context;
+       struct pci_dev *err_port = context, *err_dev;

/*

         * According to PCIe r6.0 sec 6.7.6, errors are an expected side effect
@@ -357,10 +376,11 @@ static irqreturn_t dpc_handler(int irq, void *context)
                return IRQ_HANDLED;
        }

- dpc_process_error(err_port);

+       err_dev = dpc_process_error(err_port);

/* We configure DPC so it only triggers on ERR_FATAL */

-       pcie_do_recovery(err_port, 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 521fca2f40cb..088f3e188f54 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, *err_port;
+       struct pci_dev *pdev = data, *err_port, *err_dev;
        pci_ers_result_t estate = PCI_ERS_RESULT_DISCONNECT;
        u16 status;

@@ -190,7 +190,7 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)

                goto send_ost;
        }

- dpc_process_error(err_port);

+       err_dev = dpc_process_error(err_port);
        pci_aer_raw_clear_status(err_port);

/*

@@ -198,7 +198,7 @@ static void edr_handle_event(acpi_handle handle, u32 event, 
void *data)
         * or ERR_NONFATAL, since the link is already down, use the FATAL
         * error recovery path for both cases.
         */
-       estate = pcie_do_recovery(err_port, pci_channel_io_frozen, 
dpc_reset_link);
+       estate = pcie_do_recovery(err_dev, pci_channel_io_frozen, 
dpc_reset_link);

send_ost:@@ -216,6 +216,7 @@ static void edr_handle_event(acpi_handle handle, u32 event, void *data)

pci_dev_put(err_port);

+       pci_dev_put(err_dev);


err_dev is not a valid pointer before calling dpc_process_error(). So either
initialize it with NULL or only call it in error paths after
dpc_process_error().

And btw, pci_dev_put(err_dev) should come before pci_dev_put(err_port).

- Mani


You are right.

Will send a new patch to fix it.

Thanks.
Shuai

Re: [PATCH v4 2/3] PCI/DPC: Run recovery on device that detected the error

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