[PATCH v5 3/5] PCI/DPC: Initialize info.id in dpc_process_error()

[Naveen Naidu <naveennaidu479@gmail.com>]

In the dpc_process_error() path, info.id isn't initialized before being
passed to aer_print_error(). In the corresponding AER path, it is
initialized in aer_isr_one_error().

The error message shown during Coverity Scan is:

  Coverity #1461602
  CID 1461602 (#1 of 1): Uninitialized scalar variable (UNINIT)
  8. uninit_use_in_call: Using uninitialized value info.id when calling aer_print_error.

Also Per PCIe r5.0, sec 7.9.15.5, the Source ID is defined only when the
Trigger Reason indicates ERR_NONFATAL or ERR_FATAL. Initialize the
"info.id" based on the trigger reason before passing it to
aer_print_error()

Fixes: 8aefa9b0d910 ("PCI/DPC: Print AER status in DPC event handling")
Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/pcie/dpc.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index c556e7beafe3..6fa1b1eb4671 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -262,16 +262,24 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
 
 void dpc_process_error(struct pci_dev *pdev)
 {
-	u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
+	u16 cap = pdev->dpc_cap, status, reason, ext_reason;
 	struct aer_err_info info;
 
 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
-	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
+	reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
+
+	/*
+	 * Per PCIe r5.0, sec 7.9.15.5, the Source ID is defined only when the
+	 * Trigger Reason indicates ERR_NONFATAL or ERR_FATAL.
+	 */
+	if (reason == 1 || reason == 2)
+		pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &info.id);
+	else
+		info.id = 0;
 
 	pci_info(pdev, "containment event, status:%#06x source:%#06x\n",
-		 status, source);
+		 status, info.id);
 
-	reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
 	ext_reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT) >> 5;
 	pci_warn(pdev, "%s detected\n",
 		 (reason == 0) ? "unmasked uncorrectable error" :
-- 
2.25.1