ACPI / einj: Make error paths more talkative

It is absolutely unfriendly when one sees this:

  # modprobe einj
  modprobe: ERROR: could not insert 'einj': No such device

without anything in dmesg to tell one why the load failed.

Beef up the error handling of the init function to be more user-friendly
when the load fails.

Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/apei/einj.c

@@ -692,34 +692,42 @@ static int __init einj_init(void)
 	struct dentry *fentry;
 	struct apei_exec_context ctx;
 
-	if (acpi_disabled)
+	if (acpi_disabled) {
+		pr_warn("ACPI disabled.\n");
 		return -ENODEV;
+	}
 
 	status = acpi_get_table(ACPI_SIG_EINJ, 0,
 				(struct acpi_table_header **)&einj_tab);
-	if (status == AE_NOT_FOUND)
+	if (status == AE_NOT_FOUND) {
+		pr_warn("EINJ table not found.\n");
 		return -ENODEV;
+	}
 	else if (ACPI_FAILURE(status)) {
-		const char *msg = acpi_format_exception(status);
-		pr_err("Failed to get table, %s\n", msg);
+		pr_err("Failed to get EINJ table: %s\n",
+				acpi_format_exception(status));
 		return -EINVAL;
 	}
 
 	rc = einj_check_table(einj_tab);
 	if (rc) {
-		pr_warning(FW_BUG "EINJ table is invalid\n");
+		pr_warn(FW_BUG "Invalid EINJ table.n");
 		return -EINVAL;
 	}
 
 	rc = -ENOMEM;
 	einj_debug_dir = debugfs_create_dir("einj", apei_get_debugfs_dir());
-	if (!einj_debug_dir)
+	if (!einj_debug_dir) {
+		pr_err("Error creating debugfs node.\n");
 		goto err_cleanup;
+	}
+
 	fentry = debugfs_create_file("available_error_type", S_IRUSR,
 				     einj_debug_dir, NULL,
 				     &available_error_type_fops);
 	if (!fentry)
 		goto err_cleanup;
+
 	fentry = debugfs_create_file("error_type", S_IRUSR | S_IWUSR,
 				     einj_debug_dir, NULL, &error_type_fops);
 	if (!fentry)
@@ -732,14 +740,22 @@ static int __init einj_init(void)
 	apei_resources_init(&einj_resources);
 	einj_exec_ctx_init(&ctx);
 	rc = apei_exec_collect_resources(&ctx, &einj_resources);
-	if (rc)
+	if (rc) {
+		pr_err("Error collecting EINJ resources.\n");
 		goto err_fini;
+	}
+
 	rc = apei_resources_request(&einj_resources, "APEI EINJ");
-	if (rc)
+	if (rc) {
+		pr_err("Error requesting memory/port resources.\n");
 		goto err_fini;
+	}
+
 	rc = apei_exec_pre_map_gars(&ctx);
-	if (rc)
+	if (rc) {
+		pr_err("Error pre-mapping GARs.\n");
 		goto err_release;
+	}
 
 	rc = -ENOMEM;
 	einj_param = einj_get_parameter_address();
@@ -795,6 +811,7 @@ err_unmap:
 			sizeof(struct einj_parameter);
 
 		acpi_os_unmap_iomem(einj_param, size);
+		pr_err("Error creating param extension debugfs nodes.\n");
 	}
 	apei_exec_post_unmap_gars(&ctx);
 err_release:
@@ -802,6 +819,7 @@ err_release:
 err_fini:
 	apei_resources_fini(&einj_resources);
 err_cleanup:
+	pr_err("Error creating primary debugfs nodes.\n");
 	debugfs_remove_recursive(einj_debug_dir);
 
 	return rc;