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From: Jiri Olsa <jolsa@kernel.org>
To: Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	David Ahern <dsahern@gmail.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Milind Chabbi <chabbi.milind@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>
Subject: [PATCH 4/5] perf/hw_breakpoint: Enable breakpoint in modify_user_hw_breakpoint
Date: Mon, 27 Aug 2018 11:12:27 +0200	[thread overview]
Message-ID: <20180827091228.2878-5-jolsa@kernel.org> (raw)
In-Reply-To: <20180827091228.2878-1-jolsa@kernel.org>

Currently we enable the breakpoint back only if the breakpoint
modification was successful. If it fails we can leave the
breakpoint in disabled state with attr->disabled == 0.

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

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: http://lkml.kernel.org/n/tip-79p9ttocwy2ju2s6qh25dvre@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 kernel/events/hw_breakpoint.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index 3e560d7609fd..d6b56180827c 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -523,13 +523,11 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att
 		perf_event_disable(bp);
 
 	err = modify_user_hw_breakpoint_check(bp, attr, false);
-	if (err)
-		return err;
 
-	if (!attr->disabled)
+	if (!bp->attr.disabled)
 		perf_event_enable(bp);
 
-	return 0;
+	return err;
 }
 EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint);
 
-- 
2.17.1


  parent reply	other threads:[~2018-08-27  9:12 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-27  9:12 [PATCHv4 0/5] perf/hw_breakpoint: Fix breakpoint modify Jiri Olsa
2018-08-27  9:12 ` [PATCH 1/5] perf tests: Add breakpoint modify tests Jiri Olsa
2018-09-06 13:01   ` [tip:perf/core] " tip-bot for Jiri Olsa
2018-08-27  9:12 ` [PATCH 2/5] perf/hw_breakpoint: Modify breakpoint even if the new attr has disabled set Jiri Olsa
2018-09-06 13:02   ` [tip:perf/core] " tip-bot for Jiri Olsa
2018-08-27  9:12 ` [PATCH 3/5] perf/hw_breakpoint: Remove superfluous bp->attr.disabled = 0 Jiri Olsa
2018-09-06 13:02   ` [tip:perf/core] " tip-bot for Jiri Olsa
2018-08-27  9:12 ` Jiri Olsa [this message]
2018-09-06 13:03   ` [tip:perf/core] perf/hw_breakpoint: Enable breakpoint in modify_user_hw_breakpoint tip-bot for Jiri Olsa
2018-08-27  9:12 ` [PATCH 5/5] perf/hw_breakpoint: Simplify breakpoint enable in perf_event_modify_breakpoint Jiri Olsa
2018-09-06 13:03   ` [tip:perf/core] " tip-bot for Jiri Olsa
2018-08-30 18:39 ` [PATCHv4 0/5] perf/hw_breakpoint: Fix breakpoint modify Arnaldo Carvalho de Melo
  -- strict thread matches above, loose matches on Subject: below --
2018-08-10 10:47 [PATCHv3 " Jiri Olsa
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

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