[PATCH v6 03/47] perf events x86: Use function to add missing lock

From: Ian Rogers
Date: Wed Dec 06 2023 - 20:17:43 EST


Switch 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@xxxxxxxxxx>
---
tools/perf/arch/x86/util/event.c | 103 +++++++++++++++++--------------
1 file changed, 58 insertions(+), 45 deletions(-)

diff --git a/tools/perf/arch/x86/util/event.c b/tools/perf/arch/x86/util/event.c
index 5741ffe47312..e65b7dbe27fb 100644
--- a/tools/perf/arch/x86/util/event.c
+++ b/tools/perf/arch/x86/util/event.c
@@ -14,66 +14,79 @@

#if defined(__x86_64__)

-int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
- perf_event__handler_t process,
- struct machine *machine)
+struct perf_event__synthesize_extra_kmaps_cb_args {
+ struct perf_tool *tool;
+ perf_event__handler_t process;
+ struct machine *machine;
+ union perf_event *event;
+};
+
+static int perf_event__synthesize_extra_kmaps_cb(struct map *map, void *data)
{
- int rc = 0;
- struct map_rb_node *pos;
- struct maps *kmaps = machine__kernel_maps(machine);
- union perf_event *event = zalloc(sizeof(event->mmap) +
- machine->id_hdr_size);
+ struct perf_event__synthesize_extra_kmaps_cb_args *args = data;
+ union perf_event *event = args->event;
+ struct kmap *kmap;
+ size_t size;

- if (!event) {
- pr_debug("Not enough memory synthesizing mmap event "
- "for extra kernel maps\n");
- return -1;
- }
+ if (!__map__is_extra_kernel_map(map))
+ return 0;

- maps__for_each_entry(kmaps, pos) {
- struct kmap *kmap;
- size_t size;
- struct map *map = pos->map;
+ kmap = map__kmap(map);

- if (!__map__is_extra_kernel_map(map))
- continue;
+ size = sizeof(event->mmap) - sizeof(event->mmap.filename) +
+ PERF_ALIGN(strlen(kmap->name) + 1, sizeof(u64)) +
+ args->machine->id_hdr_size;

- kmap = map__kmap(map);
+ memset(event, 0, size);

- size = sizeof(event->mmap) - sizeof(event->mmap.filename) +
- PERF_ALIGN(strlen(kmap->name) + 1, sizeof(u64)) +
- machine->id_hdr_size;
+ event->mmap.header.type = PERF_RECORD_MMAP;

- memset(event, 0, size);
+ /*
+ * kernel uses 0 for user space maps, see kernel/perf_event.c
+ * __perf_event_mmap
+ */
+ if (machine__is_host(args->machine))
+ event->header.misc = PERF_RECORD_MISC_KERNEL;
+ else
+ event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;

- event->mmap.header.type = PERF_RECORD_MMAP;
+ event->mmap.header.size = size;

- /*
- * kernel uses 0 for user space maps, see kernel/perf_event.c
- * __perf_event_mmap
- */
- if (machine__is_host(machine))
- event->header.misc = PERF_RECORD_MISC_KERNEL;
- else
- event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
+ event->mmap.start = map__start(map);
+ event->mmap.len = map__size(map);
+ event->mmap.pgoff = map__pgoff(map);
+ event->mmap.pid = args->machine->pid;

- event->mmap.header.size = size;
+ strlcpy(event->mmap.filename, kmap->name, PATH_MAX);

- event->mmap.start = map__start(map);
- event->mmap.len = map__size(map);
- event->mmap.pgoff = map__pgoff(map);
- event->mmap.pid = machine->pid;
+ if (perf_tool__process_synth_event(args->tool, event, args->machine, args->process) != 0)
+ return -1;

- strlcpy(event->mmap.filename, kmap->name, PATH_MAX);
+ return 0;
+}

- if (perf_tool__process_synth_event(tool, event, machine,
- process) != 0) {
- rc = -1;
- break;
- }
+int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
+ perf_event__handler_t process,
+ struct machine *machine)
+{
+ int rc;
+ struct maps *kmaps = machine__kernel_maps(machine);
+ struct perf_event__synthesize_extra_kmaps_cb_args args = {
+ .tool = tool,
+ .process = process,
+ .machine = machine,
+ .event = zalloc(sizeof(args.event->mmap) + machine->id_hdr_size),
+ };
+
+ if (!args.event) {
+ pr_debug("Not enough memory synthesizing mmap event "
+ "for extra kernel maps\n");
+ return -1;
}

- free(event);
+ rc = maps__for_each_map(kmaps, perf_event__synthesize_extra_kmaps_cb, &args);
+
+ free(args.event);
return rc;
}

--
2.43.0.rc2.451.g8631bc7472-goog