[PATCH v9 1/2] PCI/ERR: Call pci_bus_reset() before calling ->slot_reset() callback

[Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>]

Currently if report_error_detected() or report_mmio_enabled()
functions requests PCI_ERS_RESULT_NEED_RESET, current
pcie_do_recovery() implementation does not do the requested
explicit device reset, but instead just calls the
report_slot_reset() on all affected devices. Notifying about the
reset via report_slot_reset() without doing the actual device
reset is incorrect. So call pci_bus_reset() before triggering
->slot_reset() callback.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
---
 Changes since v7:
  * Rebased on top of v5.11-rc1.

 Changes since v7:
  * Rebased on top of v5.10-rc1.

 Changes since v6:
  * None.

 Changes since v5:
  * Added Ashok's Reviewed-by tag.

 Changes since v4:
  * Added check for pci_reset_bus() return value.

 drivers/pci/pcie/err.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 510f31f0ef6d..6c19e9948232 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -177,6 +177,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	struct pci_dev *bridge;
 	pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
 	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
+	int ret;
 
 	/*
 	 * If the error was detected by a Root Port, Downstream Port, RCEC,
@@ -214,11 +215,12 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	}
 
 	if (status == PCI_ERS_RESULT_NEED_RESET) {
-		/*
-		 * TODO: Should call platform-specific
-		 * functions to reset slot before calling
-		 * drivers' slot_reset callbacks?
-		 */
+		ret = pci_reset_bus(bridge);
+		if (ret < 0) {
+			pci_err(dev, "Failed to reset %d\n", ret);
+			status = PCI_ERS_RESULT_DISCONNECT;
+			goto failed;
+		}
 		status = PCI_ERS_RESULT_RECOVERED;
 		pci_dbg(bridge, "broadcast slot_reset message\n");
 		pci_walk_bridge(bridge, report_slot_reset, &status);
-- 
2.25.1