[PATCH 4/5] perf/hw_breakpoint: Enable breakpoint in modify_user_hw_breakpoint

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 4/5] perf/hw_breakpoint: Enable breakpoint in modify_user_hw_breakpoint
Date: Fri, 10 Aug 2018 12:47:29 +0200	[thread overview]
Message-ID: <20180810104730.3293-5-jolsa@kernel.org> (raw)
In-Reply-To: <20180810104730.3293-1-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>
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

