PCI/AER: Convert aer_get_device_error_info(), aer_print_error() to index

Previously aer_get_device_error_info() and aer_print_error() took a pointer
to struct aer_err_info and a pointer to a pci_dev.  Typically the pci_dev
was one of the elements of the aer_err_info.dev[] array (DPC was an
exception, where the dev[] array was unused).

Convert aer_get_device_error_info() and aer_print_error() to take an index
into the aer_err_info.dev[] array instead.  A future patch will add
per-device ratelimit information, so the index makes it convenient to find
the ratelimit associated with the device.

To accommodate DPC, set info->dev[0] to the DPC port before using these
interfaces.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://patch.msgid.link/20250522232339.1525671-17-helgaas@kernel.org

Author: bjorn-helgaas

drivers/pci/pci.h

@@ -605,8 +605,8 @@ struct aer_err_info {
 	struct pcie_tlp_log tlp;	/* TLP Header */
 };
 
-int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info);
-void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
+int aer_get_device_error_info(struct aer_err_info *info, int i);
+void aer_print_error(struct aer_err_info *info, int i);
 
 int pcie_read_tlp_log(struct pci_dev *dev, int where, int where2,
 		      unsigned int tlp_len, bool flit,

drivers/pci/pcie/aer.c

@@ -705,12 +705,18 @@ static void aer_print_source(struct pci_dev *dev, struct aer_err_info *info,
 		 found ? "" : " (no details found");
 }
 
-void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
+void aer_print_error(struct aer_err_info *info, int i)
 {
-	int layer, agent;
-	int id = pci_dev_id(dev);
+	struct pci_dev *dev;
+	int layer, agent, id;
 	const char *level = info->level;
 
+	if (WARN_ON_ONCE(i >= AER_MAX_MULTI_ERR_DEVICES))
+		return;
+
+	dev = info->dev[i];
+	id = pci_dev_id(dev);
+
 	pci_dev_aer_stats_incr(dev, info);
 	trace_aer_event(pci_name(dev), (info->status & ~info->mask),
 			info->severity, info->tlp_header_valid, &info->tlp);
@@ -1193,19 +1199,26 @@ EXPORT_SYMBOL_GPL(aer_recover_queue);
 
 /**
  * aer_get_device_error_info - read error status from dev and store it to info
- * @dev: pointer to the device expected to have an error record
  * @info: pointer to structure to store the error record
+ * @i: index into info->dev[]
  *
  * Return: 1 on success, 0 on error.
  *
  * Note that @info is reused among all error devices. Clear fields properly.
  */
-int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
+int aer_get_device_error_info(struct aer_err_info *info, int i)
 {
-	int type = pci_pcie_type(dev);
-	int aer = dev->aer_cap;
+	struct pci_dev *dev;
+	int type, aer;
 	u32 aercc;
 
+	if (i >= AER_MAX_MULTI_ERR_DEVICES)
+		return 0;
+
+	dev = info->dev[i];
+	aer = dev->aer_cap;
+	type = pci_pcie_type(dev);
+
 	/* Must reset in this function */
 	info->status = 0;
 	info->tlp_header_valid = 0;
@@ -1257,11 +1270,11 @@ static inline void aer_process_err_devices(struct aer_err_info *e_info)
 
 	/* Report all before handling them, to not lose records by reset etc. */
 	for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
-		if (aer_get_device_error_info(e_info->dev[i], e_info))
-			aer_print_error(e_info->dev[i], e_info);
+		if (aer_get_device_error_info(e_info, i))
+			aer_print_error(e_info, i);
 	}
 	for (i = 0; i < e_info->error_dev_num && e_info->dev[i]; i++) {
-		if (aer_get_device_error_info(e_info->dev[i], e_info))
+		if (aer_get_device_error_info(e_info, i))
 			handle_error_source(e_info->dev[i], e_info);
 	}
 }

drivers/pci/pcie/dpc.c

@@ -253,6 +253,10 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
 		info->severity = AER_NONFATAL;
 
 	info->level = KERN_ERR;
+
+	info->dev[0] = dev;
+	info->error_dev_num = 1;
+
 	return 1;
 }
 
@@ -270,8 +274,8 @@ void dpc_process_error(struct pci_dev *pdev)
 		pci_warn(pdev, "containment event, status:%#06x: unmasked uncorrectable error detected\n",
 			 status);
 		if (dpc_get_aer_uncorrect_severity(pdev, &info) &&
-		    aer_get_device_error_info(pdev, &info)) {
-			aer_print_error(pdev, &info);
+		    aer_get_device_error_info(&info, 0)) {
+			aer_print_error(&info, 0);
 			pci_aer_clear_nonfatal_status(pdev);
 			pci_aer_clear_fatal_status(pdev);
 		}