[PATCH v3 37/57] perf: Simplify perf_read_group()
Peter Zijlstra
peterz at infradead.org
Mon Jun 12 09:07:50 UTC 2023
Signed-off-by: Peter Zijlstra (Intel) <peterz at infradead.org>
---
kernel/events/core.c | 30 +++++++++++-------------------
1 file changed, 11 insertions(+), 19 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5472,11 +5472,10 @@ static int perf_read_group(struct perf_e
struct perf_event *leader = event->group_leader, *child;
struct perf_event_context *ctx = leader->ctx;
int ret;
- u64 *values;
lockdep_assert_held(&ctx->mutex);
- values = kzalloc(event->read_size, GFP_KERNEL);
+ u64 *values __free(kfree) = kzalloc(event->read_size, GFP_KERNEL);
if (!values)
return -ENOMEM;
@@ -5486,29 +5485,22 @@ static int perf_read_group(struct perf_e
* By locking the child_mutex of the leader we effectively
* lock the child list of all siblings.. XXX explain how.
*/
- mutex_lock(&leader->child_mutex);
-
- ret = __perf_read_group_add(leader, read_format, values);
- if (ret)
- goto unlock;
-
- list_for_each_entry(child, &leader->child_list, child_list) {
- ret = __perf_read_group_add(child, read_format, values);
+ scoped_guard (mutex, &leader->child_mutex) {
+ ret = __perf_read_group_add(leader, read_format, values);
if (ret)
- goto unlock;
- }
+ return ret;
- mutex_unlock(&leader->child_mutex);
+ list_for_each_entry(child, &leader->child_list, child_list) {
+ ret = __perf_read_group_add(child, read_format, values);
+ if (ret)
+ return ret;
+ }
+ }
ret = event->read_size;
if (copy_to_user(buf, values, event->read_size))
- ret = -EFAULT;
- goto out;
+ return -EFAULT;
-unlock:
- mutex_unlock(&leader->child_mutex);
-out:
- kfree(values);
return ret;
}
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