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From:   kan.liang@linux.intel.com
To:     peterz@infradead.org, acme@kernel.org, mingo@kernel.org,
        linux-kernel@vger.kernel.org
Cc:     tglx@linutronix.de, bp@alien8.de, namhyung@kernel.org,
        jolsa@redhat.com, ak@linux.intel.com, yao.jin@linux.intel.com,
        alexander.shishkin@linux.intel.com, adrian.hunter@intel.com,
        Kan Liang <kan.liang@linux.intel.com>
Subject: [PATCH 14/49] perf/x86: Remove temporary pmu assignment in event_init
Date:   Mon,  8 Feb 2021 07:25:11 -0800
Message-Id: <1612797946-18784-15-git-send-email-kan.liang@linux.intel.com>
In-Reply-To: <1612797946-18784-1-git-send-email-kan.liang@linux.intel.com>
References: <1612797946-18784-1-git-send-email-kan.liang@linux.intel.com>
Precedence: bulk

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

The temporary pmu assignment in event_init is unnecessary.

The assignment was introduced by commit 8113070d6639 ("perf_events:
Add fast-path to the rescheduling code"). At that time, event->pmu is
not assigned yet when initializing an event. The assignment is required.
However, from commit 7e5b2a01d2ca ("perf: provide PMU when initing
events"), the event->pmu is provided before event_init is invoked.
The temporary pmu assignment in event_init should be removed.

Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
 arch/x86/events/core.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 29dee3f..bdcd3ad 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2294,7 +2294,6 @@ static int validate_group(struct perf_event *event)
 
 static int x86_pmu_event_init(struct perf_event *event)
 {
-	struct pmu *tmp;
 	int err;
 
 	switch (event->attr.type) {
@@ -2309,20 +2308,10 @@ static int x86_pmu_event_init(struct perf_event *event)
 
 	err = __x86_pmu_event_init(event);
 	if (!err) {
-		/*
-		 * we temporarily connect event to its pmu
-		 * such that validate_group() can classify
-		 * it as an x86 event using is_x86_event()
-		 */
-		tmp = event->pmu;
-		event->pmu = &pmu;
-
 		if (event->group_leader != event)
 			err = validate_group(event);
 		else
 			err = validate_event(event);
-
-		event->pmu = tmp;
 	}
 	if (err) {
 		if (event->destroy)
-- 
2.7.4