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From: Jiri Olsa <jolsa@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	David Ahern <dsahern@gmail.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Milind Chabbi <chabbi.milind@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Frederic Weisbecker <frederic@kernel.org>
Subject: [PATCH 5/5] perf/hw_breakpoint: Simplify breakpoint enable in perf_event_modify_breakpoint
Date: Fri, 10 Aug 2018 12:47:30 +0200	[thread overview]
Message-ID: <20180810104730.3293-6-jolsa@kernel.org> (raw)
In-Reply-To: <20180810104730.3293-1-jolsa@kernel.org>

We can safely enable the breakpoint back for both the fail
and success paths by checking only the bp->attr.disabled,
which either holds the new 'requested' disabled state or
the original breakpoint state.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/n/tip-vo1jm1u2nar6lj6hnd9g73ug@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 kernel/events/core.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f6ea33a9f904..22ede28ec07d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2867,16 +2867,11 @@ static int perf_event_modify_breakpoint(struct perf_event *bp,
 	_perf_event_disable(bp);
 
 	err = modify_user_hw_breakpoint_check(bp, attr, true);
-	if (err) {
-		if (!bp->attr.disabled)
-			_perf_event_enable(bp);
 
-		return err;
-	}
-
-	if (!attr->disabled)
+	if (!bp->attr.disabled)
 		_perf_event_enable(bp);
-	return 0;
+
+	return err;
 }
 
 static int perf_event_modify_attr(struct perf_event *event,
-- 
2.17.1


  parent reply	other threads:[~2018-08-10 10:47 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-10 10:47 [PATCHv3 0/5] perf/hw_breakpoint: Fix breakpoint modify Jiri Olsa
2018-08-10 10:47 ` [PATCH 1/5] perf tests: Add breakpoint modify tests Jiri Olsa
2018-08-10 10:47 ` [PATCH 2/5] perf/hw_breakpoint: Modify breakpoint even if the new attr has disabled set Jiri Olsa
2018-08-17 14:27   ` Frederic Weisbecker
2018-08-10 10:47 ` [PATCH 3/5] perf/hw_breakpoint: Remove superfluous bp->attr.disabled = 0 Jiri Olsa
2018-08-17 14:47   ` Frederic Weisbecker
2018-08-10 10:47 ` [PATCH 4/5] perf/hw_breakpoint: Enable breakpoint in modify_user_hw_breakpoint Jiri Olsa
2018-08-14 10:32   ` Oleg Nesterov
2018-08-17 14:50   ` Frederic Weisbecker
2018-08-10 10:47 ` Jiri Olsa [this message]
2018-08-14 10:32   ` [PATCH 5/5] perf/hw_breakpoint: Simplify breakpoint enable in perf_event_modify_breakpoint Oleg Nesterov
2018-08-17 11:48 ` [PATCHv3 0/5] perf/hw_breakpoint: Fix breakpoint modify Jiri Olsa
2018-08-27  9:12 [PATCHv4 " Jiri Olsa
2018-08-27  9:12 ` [PATCH 5/5] perf/hw_breakpoint: Simplify breakpoint enable in perf_event_modify_breakpoint Jiri Olsa

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