linux-kernel - [PATCH v3 07/15] perf pmu: Use fd rather than FILE from new

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Message-ID: <20250828205930.4007284-8-irogers@google.com>
Date: Thu, 28 Aug 2025 13:59:22 -0700
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, James Clark <james.clark@...aro.org>, 
	Xu Yang <xu.yang_2@....com>, Thomas Falcon <thomas.falcon@...el.com>, 
	Andi Kleen <ak@...ux.intel.com>, linux-kernel@...r.kernel.org, 
	linux-perf-users@...r.kernel.org, bpf@...r.kernel.org, 
	Atish Patra <atishp@...osinc.com>, Beeman Strong <beeman@...osinc.com>, Leo Yan <leo.yan@....com>, 
	Vince Weaver <vincent.weaver@...ne.edu>
Subject: [PATCH v3 07/15] perf pmu: Use fd rather than FILE from new_alias

The FILE argument was necessary for the scanner but now that
functionality is not being used we can switch to just using
io__getline which should cut down on stdio buffer usage.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/pmu.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index b44dfe4c73fc..818be59db2c6 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -563,7 +563,7 @@ static int update_alias(const struct pmu_event *pe,
 }
 
 static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
-				const char *desc, const char *val, FILE *val_fd,
+				const char *desc, const char *val, int val_fd,
 			        const struct pmu_event *pe, enum event_source src)
 {
 	struct perf_pmu_alias *alias, *old_alias;
@@ -614,12 +614,15 @@ static int perf_pmu__new_alias(struct perf_pmu *pmu, const char *name,
 	if (ret)
 		return ret;
 
-	if (!val_fd) {
+	if (val_fd < 0) {
 		alias->terms = strdup(val);
 	} else {
+		char buf[256];
+		struct io io;
 		size_t line_len;
 
-		ret = getline(&alias->terms, &line_len, val_fd) < 0 ? -errno : 0;
+		io__init(&io, val_fd, buf, sizeof(buf));
+		ret = io__getline(&io, &alias->terms, &line_len) < 0 ? -errno : 0;
 		if (ret) {
 			pr_err("Failed to read alias %s\n", name);
 			return ret;
@@ -698,7 +701,6 @@ static int __pmu_aliases_parse(struct perf_pmu *pmu, int events_dir_fd)
 	while ((evt_ent = io_dir__readdir(&event_dir))) {
 		char *name = evt_ent->d_name;
 		int fd;
-		FILE *file;
 
 		if (!strcmp(name, ".") || !strcmp(name, ".."))
 			continue;
@@ -714,17 +716,12 @@ static int __pmu_aliases_parse(struct perf_pmu *pmu, int events_dir_fd)
 			pr_debug("Cannot open %s\n", name);
 			continue;
 		}
-		file = fdopen(fd, "r");
-		if (!file) {
-			close(fd);
-			continue;
-		}
 
 		if (perf_pmu__new_alias(pmu, name, /*desc=*/ NULL,
-					/*val=*/ NULL, file, /*pe=*/ NULL,
+					/*val=*/ NULL, fd, /*pe=*/ NULL,
 					EVENT_SRC_SYSFS) < 0)
 			pr_debug("Cannot set up %s\n", name);
-		fclose(file);
+		close(fd);
 	}
 
 	pmu->sysfs_aliases_loaded = true;
@@ -1041,7 +1038,7 @@ static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe,
 {
 	struct perf_pmu *pmu = vdata;
 
-	perf_pmu__new_alias(pmu, pe->name, pe->desc, pe->event, /*val_fd=*/ NULL,
+	perf_pmu__new_alias(pmu, pe->name, pe->desc, pe->event, /*val_fd=*/ -1,
 			    pe, EVENT_SRC_CPU_JSON);
 	return 0;
 }
@@ -1090,7 +1087,7 @@ static int pmu_add_sys_aliases_iter_fn(const struct pmu_event *pe,
 				pe->name,
 				pe->desc,
 				pe->event,
-				/*val_fd=*/ NULL,
+				/*val_fd=*/ -1,
 				pe,
 				EVENT_SRC_SYS_JSON);
 	}
-- 
2.51.0.318.gd7df087d1a-goog