perf stat: Helper functions for PCIe root ports list in iostat mode

Introduce helper functions to control PCIe root ports list.
These helpers will be used in the follow-up patch.

Signed-off-by: Alexander Antonov <[e-mail]>
Acked-by: Namhyung Kim <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Alexey V Bayduraev <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/arch/x86/util/iostat.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * perf iostat
+ *
+ * Copyright (C) 2020, Intel Corporation
+ *
+ * Authors: Alexander Antonov <[e-mail]>
+ */
+
+#include <api/fs/fs.h>
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <limits.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <regex.h>
+#include "util/cpumap.h"
+#include "util/debug.h"
+#include "util/iostat.h"
+#include "util/counts.h"
+#include "path.h"
+
+struct iio_root_port {
+	u32 domain;
+	u8 bus;
+	u8 die;
+	u8 pmu_idx;
+	int idx;
+};
+
+struct iio_root_ports_list {
+	struct iio_root_port **rps;
+	int nr_entries;
+};
+
+static void iio_root_port_show(FILE *output,
+			       const struct iio_root_port * const rp)
+{
+	if (output && rp)
+		fprintf(output, "S%d-uncore_iio_%d<%04x:%02x>\n",
+			rp->die, rp->pmu_idx, rp->domain, rp->bus);
+}
+
+static struct iio_root_port *iio_root_port_new(u32 domain, u8 bus,
+					       u8 die, u8 pmu_idx)
+{
+	struct iio_root_port *p = calloc(1, sizeof(*p));
+
+	if (p) {
+		p->domain = domain;
+		p->bus = bus;
+		p->die = die;
+		p->pmu_idx = pmu_idx;
+	}
+	return p;
+}
+
+static void iio_root_ports_list_free(struct iio_root_ports_list *list)
+{
+	int idx;
+
+	if (list) {
+		for (idx = 0; idx < list->nr_entries; idx++)
+			free(list->rps[idx]);
+		free(list->rps);
+		free(list);
+	}
+}
+
+static struct iio_root_port *iio_root_port_find_by_notation(
+	const struct iio_root_ports_list * const list, u32 domain, u8 bus)
+{
+	int idx;
+	struct iio_root_port *rp;
+
+	if (list) {
+		for (idx = 0; idx < list->nr_entries; idx++) {
+			rp = list->rps[idx];
+			if (rp && rp->domain == domain && rp->bus == bus)
+				return rp;
+		}
+	}
+	return NULL;
+}
+
+static int iio_root_ports_list_insert(struct iio_root_ports_list *list,
+				      struct iio_root_port * const rp)
+{
+	struct iio_root_port **tmp_buf;
+
+	if (list && rp) {
+		rp->idx = list->nr_entries++;
+		tmp_buf = realloc(list->rps,
+				  list->nr_entries * sizeof(*list->rps));
+		if (!tmp_buf) {
+			pr_err("Failed to realloc memory\n");
+			return -ENOMEM;
+		}
+		tmp_buf[rp->idx] = rp;
+		list->rps = tmp_buf;
+	}
+	return 0;
+}