linux-kernel - [PATCH 13/21] perf/core: Factor out functions to allocate/free the task_ctx

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Date:   Fri, 19 Jun 2020 07:04:01 -0700
From:   kan.liang@...ux.intel.com
To:     peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        tglx@...utronix.de, bp@...en8.de, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, namhyung@...nel.org, dave.hansen@...el.com,
        yu-cheng.yu@...el.com, bigeasy@...utronix.de, gorcunov@...il.com,
        hpa@...or.com, alexey.budankov@...ux.intel.com, eranian@...gle.com,
        ak@...ux.intel.com, like.xu@...ux.intel.com,
        yao.jin@...ux.intel.com, Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH 13/21] perf/core: Factor out functions to allocate/free the task_ctx_data

From: Kan Liang <kan.liang@...ux.intel.com>

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@...ux.intel.com>
---
 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 633b4ae..a9bfe32 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1234,12 +1234,22 @@ 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);
 }
 
@@ -4467,7 +4477,7 @@ 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;
@@ -4525,11 +4535,11 @@ find_get_context(struct pmu *pmu, struct task_struct *task,
 		}
 	}
 
-	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);
 }
 
@@ -12406,8 +12416,7 @@ 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);
-- 
2.7.4