[PATCH v3 2/7] perf: Use perf_pmu__open_file() and perf_pmu__scan_file()

From: James Clark
Date: Tue Jan 03 2023 - 11:22:46 EST


Remove some code that duplicates existing methods. This requires that
some consts are removed because one of the existing helper methods takes
a struct perf_pmu instead of a name which has a non const name field.
But except for the tests, the strings were already non const.

No functional changes.

Signed-off-by: James Clark <james.clark@xxxxxxx>
---
tools/perf/util/cputopo.c | 9 +-------
tools/perf/util/pmu-hybrid.c | 27 +++++-------------------
tools/perf/util/pmu.c | 40 +++++++++++-------------------------
tools/perf/util/pmu.h | 3 ++-
4 files changed, 20 insertions(+), 59 deletions(-)

diff --git a/tools/perf/util/cputopo.c b/tools/perf/util/cputopo.c
index 1a3ff6449158..e08797c3cdbc 100644
--- a/tools/perf/util/cputopo.c
+++ b/tools/perf/util/cputopo.c
@@ -422,8 +422,6 @@ void numa_topology__delete(struct numa_topology *tp)
static int load_hybrid_node(struct hybrid_topology_node *node,
struct perf_pmu *pmu)
{
- const char *sysfs;
- char path[PATH_MAX];
char *buf = NULL, *p;
FILE *fp;
size_t len = 0;
@@ -432,12 +430,7 @@ static int load_hybrid_node(struct hybrid_topology_node *node,
if (!node->pmu_name)
return -1;

- sysfs = sysfs__mountpoint();
- if (!sysfs)
- goto err;
-
- snprintf(path, PATH_MAX, CPUS_TEMPLATE_CPU, sysfs, pmu->name);
- fp = fopen(path, "r");
+ fp = perf_pmu__open_file(pmu, "cpus");
if (!fp)
goto err;

diff --git a/tools/perf/util/pmu-hybrid.c b/tools/perf/util/pmu-hybrid.c
index f51ccaac60ee..38628805a952 100644
--- a/tools/perf/util/pmu-hybrid.c
+++ b/tools/perf/util/pmu-hybrid.c
@@ -20,32 +20,15 @@ LIST_HEAD(perf_pmu__hybrid_pmus);

bool perf_pmu__hybrid_mounted(const char *name)
{
- char path[PATH_MAX];
- const char *sysfs;
- FILE *file;
- int n, cpu;
+ int cpu;
+ char pmu_name[PATH_MAX];
+ struct perf_pmu pmu = {.name = pmu_name};

if (strncmp(name, "cpu_", 4))
return false;

- sysfs = sysfs__mountpoint();
- if (!sysfs)
- return false;
-
- snprintf(path, PATH_MAX, CPUS_TEMPLATE_CPU, sysfs, name);
- if (!file_available(path))
- return false;
-
- file = fopen(path, "r");
- if (!file)
- return false;
-
- n = fscanf(file, "%u", &cpu);
- fclose(file);
- if (n <= 0)
- return false;
-
- return true;
+ strlcpy(pmu_name, name, sizeof(pmu_name));
+ return perf_pmu__scan_file(&pmu, "cpus", "%u", &cpu) > 0;
}

struct perf_pmu *perf_pmu__find_hybrid_pmu(const char *name)
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 0d9619dde3a8..683cc7953f11 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -570,45 +570,31 @@ static void pmu_read_sysfs(void)
closedir(dir);
}

-static struct perf_cpu_map *__pmu_cpumask(const char *path)
-{
- FILE *file;
- struct perf_cpu_map *cpus;
-
- file = fopen(path, "r");
- if (!file)
- return NULL;
-
- cpus = perf_cpu_map__read(file);
- fclose(file);
- return cpus;
-}
-
/*
* Uncore PMUs have a "cpumask" file under sysfs. CPU PMUs (e.g. on arm/arm64)
* may have a "cpus" file.
*/
#define SYS_TEMPLATE_ID "./bus/event_source/devices/%s/identifier"
-#define CPUS_TEMPLATE_UNCORE "%s/bus/event_source/devices/%s/cpumask"

static struct perf_cpu_map *pmu_cpumask(const char *name)
{
- char path[PATH_MAX];
struct perf_cpu_map *cpus;
- const char *sysfs = sysfs__mountpoint();
const char *templates[] = {
- CPUS_TEMPLATE_UNCORE,
- CPUS_TEMPLATE_CPU,
+ "cpumask",
+ "cpus",
NULL
};
const char **template;
+ char pmu_name[PATH_MAX];
+ struct perf_pmu pmu = {.name = pmu_name};
+ FILE *file;

- if (!sysfs)
- return NULL;
-
+ strlcpy(pmu_name, name, sizeof(pmu_name));
for (template = templates; *template; template++) {
- snprintf(path, PATH_MAX, *template, sysfs, name);
- cpus = __pmu_cpumask(path);
+ file = perf_pmu__open_file(&pmu, *template);
+ if (!file)
+ continue;
+ cpus = perf_cpu_map__read(file);
if (cpus)
return cpus;
}
@@ -619,13 +605,11 @@ static struct perf_cpu_map *pmu_cpumask(const char *name)
static bool pmu_is_uncore(const char *name)
{
char path[PATH_MAX];
- const char *sysfs;

if (perf_pmu__hybrid_mounted(name))
return false;

- sysfs = sysfs__mountpoint();
- snprintf(path, PATH_MAX, CPUS_TEMPLATE_UNCORE, sysfs, name);
+ perf_pmu__pathname_scnprintf(path, sizeof(path), name, "cpumask");
return file_available(path);
}

@@ -1736,7 +1720,7 @@ bool pmu_have_event(const char *pname, const char *name)
return false;
}

-static FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name)
+FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name)
{
char path[PATH_MAX];

diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
index 2f2bb0286e2a..8f39e2d17fb1 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -2,6 +2,7 @@
#ifndef __PMU_H
#define __PMU_H

+#include <bits/types/FILE.h>
#include <linux/bitmap.h>
#include <linux/compiler.h>
#include <linux/perf_event.h>
@@ -22,7 +23,6 @@ enum {
};

#define PERF_PMU_FORMAT_BITS 64
-#define CPUS_TEMPLATE_CPU "%s/bus/event_source/devices/%s/cpus"
#define MAX_PMU_NAME_LEN 128

struct perf_event_attr;
@@ -261,5 +261,6 @@ char *pmu_find_alias_name(const char *name);
int perf_pmu__event_source_devices_scnprintf(char *pathname, size_t size);
int perf_pmu__pathname_scnprintf(char *buf, size_t size,
const char *pmu_name, const char *filename);
+FILE *perf_pmu__open_file(struct perf_pmu *pmu, const char *name);

#endif /* __PMU_H */
--
2.25.1