[tip:perf/core] perf_event: Make software events work again

[tip-bot for Paul Mackerras]

Commit-ID:  6e85158cf5a2385264316870256fb6ad681156a0
Gitweb:     http://git.kernel.org/tip/6e85158cf5a2385264316870256fb6ad681156a0
Author:     Paul Mackerras <paulus@xxxxxxxxx>
AuthorDate: Sat, 8 May 2010 20:58:00 +1000
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sat, 8 May 2010 13:16:55 +0200

perf_event: Make software events work again

Commit 6bde9b6ce0127e2a56228a2071536d422be31336 ("perf: Add
group scheduling transactional APIs") added code to allow a
group to be scheduled in a single transaction.  However, it
introduced a bug in handling events whose pmu does not implement
transactions -- at the end of scheduling in the events in the
group, in the non-transactional case the code now falls through
to the group_error label, and proceeds to unschedule all the
events in the group and return failure.

This fixes it by returning 0 (success) in the non-transactional
case.

Signed-off-by: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Lin Ming <ming.m.lin@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: eranian@xxxxxxxxx
LKML-Reference: <20100508105800.GB10650@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
 kernel/perf_event.c |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index bb06382..180151f 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -664,13 +664,13 @@ group_sched_in(struct perf_event *group_event,
 		}
 	}
 
-	if (txn) {
-		ret = pmu->commit_txn(pmu);
-		if (!ret) {
-			pmu->cancel_txn(pmu);
+	if (!txn)
+		return 0;
 
-			return 0;
-		}
+	ret = pmu->commit_txn(pmu);
+	if (!ret) {
+		pmu->cancel_txn(pmu);
+		return 0;
 	}
 
 group_error:
--
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