linux-kernel - [PATCH v6 07/47] perf probe-event: Use function to add missing maps lock

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Message-Id: <20231207011722.1220634-8-irogers@google.com>
Date:   Wed,  6 Dec 2023 17:16:41 -0800
From:   Ian Rogers <irogers@...gle.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Nick Terrell <terrelln@...com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
        Huacai Chen <chenhuacai@...nel.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Vincent Whitchurch <vincent.whitchurch@...s.com>,
        "Steinar H. Gunderson" <sesse@...gle.com>,
        Liam Howlett <liam.howlett@...cle.com>,
        Miguel Ojeda <ojeda@...nel.org>,
        Colin Ian King <colin.i.king@...il.com>,
        Dmitrii Dolgov <9erthalion6@...il.com>,
        Yang Jihong <yangjihong1@...wei.com>,
        Ming Wang <wangming01@...ngson.cn>,
        James Clark <james.clark@....com>,
        K Prateek Nayak <kprateek.nayak@....com>,
        Sean Christopherson <seanjc@...gle.com>,
        Leo Yan <leo.yan@...aro.org>,
        Ravi Bangoria <ravi.bangoria@....com>,
        German Gomez <german.gomez@....com>,
        Changbin Du <changbin.du@...wei.com>,
        Paolo Bonzini <pbonzini@...hat.com>, Li Dong <lidong@...o.com>,
        Sandipan Das <sandipan.das@....com>,
        liuwenyu <liuwenyu7@...wei.com>, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org,
        Guilherme Amadio <amadio@...too.org>
Subject: [PATCH v6 07/47] perf probe-event: Use function to add missing maps lock

Switch kernel_get_module_map from loop macro maps__for_each_entry to
maps__for_each_map function that takes a callback. The function holds
the maps lock, which should be held during iteration.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/probe-event.c | 40 +++++++++++++++++++++++------------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 1a5b7fa459b2..a1a796043691 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -149,10 +149,32 @@ static int kernel_get_symbol_address_by_name(const char *name, u64 *addr,
 	return 0;
 }
 
+struct kernel_get_module_map_cb_args {
+	const char *module;
+	struct map *result;
+};
+
+static int kernel_get_module_map_cb(struct map *map, void *data)
+{
+	struct kernel_get_module_map_cb_args *args = data;
+	struct dso *dso = map__dso(map);
+	const char *short_name = dso->short_name; /* short_name is "[module]" */
+	u16 short_name_len =  dso->short_name_len;
+
+	if (strncmp(short_name + 1, args->module, short_name_len - 2) == 0 &&
+	    args->module[short_name_len - 2] == '\0') {
+		args->result = map__get(map);
+		return 1;
+	}
+	return 0;
+}
+
 static struct map *kernel_get_module_map(const char *module)
 {
-	struct maps *maps = machine__kernel_maps(host_machine);
-	struct map_rb_node *pos;
+	struct kernel_get_module_map_cb_args args = {
+		.module = module,
+		.result = NULL,
+	};
 
 	/* A file path -- this is an offline module */
 	if (module && strchr(module, '/'))
@@ -164,19 +186,9 @@ static struct map *kernel_get_module_map(const char *module)
 		return map__get(map);
 	}
 
-	maps__for_each_entry(maps, pos) {
-		/* short_name is "[module]" */
-		struct dso *dso = map__dso(pos->map);
-		const char *short_name = dso->short_name;
-		u16 short_name_len =  dso->short_name_len;
+	maps__for_each_map(machine__kernel_maps(host_machine), kernel_get_module_map_cb, &args);
 
-		if (strncmp(short_name + 1, module,
-			    short_name_len - 2) == 0 &&
-		    module[short_name_len - 2] == '\0') {
-			return map__get(pos->map);
-		}
-	}
-	return NULL;
+	return args.result;
 }
 
 struct map *get_target_map(const char *target, struct nsinfo *nsi, bool user)
-- 
2.43.0.rc2.451.g8631bc7472-goog