linux-kernel - [tip: perf/core] perf/x86: Remove temporary pmu assignment in event

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Date:   Tue, 20 Apr 2021 10:46:45 -0000
From:   "tip-bot2 for Kan Liang" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Kan Liang <kan.liang@...ux.intel.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Andi Kleen <ak@...ux.intel.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: perf/core] perf/x86: Remove temporary pmu assignment in event_init

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

Commit-ID:     b98567298bad891774054113690b30bd90d5738d
Gitweb:        https://git.kernel.org/tip/b98567298bad891774054113690b30bd90d5738d
Author:        Kan Liang <kan.liang@...ux.intel.com>
AuthorDate:    Mon, 12 Apr 2021 07:30:54 -07:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Mon, 19 Apr 2021 20:03:27 +02:00

perf/x86: Remove temporary pmu assignment in event_init

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.

Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Andi Kleen <ak@...ux.intel.com>
Link: https://lkml.kernel.org/r/1618237865-33448-15-git-send-email-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 57d3fe1..ed8dcfb 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2291,7 +2291,6 @@ out:
 
 static int x86_pmu_event_init(struct perf_event *event)
 {
-	struct pmu *tmp;
 	int err;
 
 	switch (event->attr.type) {
@@ -2306,20 +2305,10 @@ 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)