[tip: perf/core] perf/core: Factor out functions to allocate/free the task_ctx_data

["tip-bot2 for Kan Liang" <tip-bot2@xxxxxxxxxxxxx>]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     ff9ff926889dd8026b4ba55266a010c27f68604f
Gitweb:        https://git.kernel.org/tip/ff9ff926889dd8026b4ba55266a010c27f68604f
Author:        Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
AuthorDate:    Fri, 03 Jul 2020 05:49:21 -07:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 08 Jul 2020 11:38:54 +02:00

perf/core: Factor out functions to allocate/free the task_ctx_data

The method to allocate/free the task_ctx_data is going to be changed in
the following patch. Currently, the task_ctx_data is allocated/freed in
several different places. To avoid repeatedly modifying the same codes
in several different places, alloc_task_ctx_data() and
free_task_ctx_data() are factored out to allocate/free the
task_ctx_data. The modification only needs to be applied once.

Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/1593780569-62993-16-git-send-email-kan.liang@xxxxxxxxxxxxxxx
---
 kernel/events/core.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9b8f925..7509040 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1238,12 +1238,22 @@ static void get_ctx(struct perf_event_context *ctx)
 	refcount_inc(&ctx->refcount);
 }
 
+static void *alloc_task_ctx_data(struct pmu *pmu)
+{
+	return kzalloc(pmu->task_ctx_size, GFP_KERNEL);
+}
+
+static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
+{
+	kfree(task_ctx_data);
+}
+
 static void free_ctx(struct rcu_head *head)
 {
 	struct perf_event_context *ctx;
 
 	ctx = container_of(head, struct perf_event_context, rcu_head);
-	kfree(ctx->task_ctx_data);
+	free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
 	kfree(ctx);
 }
 
@@ -4471,7 +4481,7 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
 		goto errout;
 
 	if (event->attach_state & PERF_ATTACH_TASK_DATA) {
-		task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
+		task_ctx_data = alloc_task_ctx_data(pmu);
 		if (!task_ctx_data) {
 			err = -ENOMEM;
 			goto errout;
@@ -4529,11 +4539,11 @@ retry:
 		}
 	}
 
-	kfree(task_ctx_data);
+	free_task_ctx_data(pmu, task_ctx_data);
 	return ctx;
 
 errout:
-	kfree(task_ctx_data);
+	free_task_ctx_data(pmu, task_ctx_data);
 	return ERR_PTR(err);
 }
 
@@ -12497,8 +12507,7 @@ inherit_event(struct perf_event *parent_event,
 	    !child_ctx->task_ctx_data) {
 		struct pmu *pmu = child_event->pmu;
 
-		child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
-						   GFP_KERNEL);
+		child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
 		if (!child_ctx->task_ctx_data) {
 			free_event(child_event);
 			return ERR_PTR(-ENOMEM);