Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753451Ab3HVOO4 (ORCPT ); Thu, 22 Aug 2013 10:14:56 -0400 Received: from mail-bk0-f44.google.com ([209.85.214.44]:40684 "EHLO mail-bk0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753381Ab3HVOOw (ORCPT ); Thu, 22 Aug 2013 10:14:52 -0400 From: Robert Richter To: Peter Zijlstra Cc: Ingo Molnar , Arnaldo Carvalho de Melo , Borislav Petkov , Jiri Olsa , linux-kernel@vger.kernel.org, Robert Richter , Robert Richter Subject: [PATCH v3 10/12] perf, persistent: Implement reference counter for events Date: Thu, 22 Aug 2013 16:13:25 +0200 Message-Id: <1377180807-12758-11-git-send-email-rric@kernel.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1377180807-12758-1-git-send-email-rric@kernel.org> References: <1377180807-12758-1-git-send-email-rric@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2399 Lines: 91 From: Robert Richter We need this later for proper event removal. Signed-off-by: Robert Richter Signed-off-by: Robert Richter --- kernel/events/persistent.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/kernel/events/persistent.c b/kernel/events/persistent.c index f23270b..70446ae 100644 --- a/kernel/events/persistent.c +++ b/kernel/events/persistent.c @@ -9,6 +9,7 @@ #define CPU_BUFFER_NR_PAGES ((512 * 1024) / PAGE_SIZE) struct pevent { + atomic_t refcount; struct perf_pmu_events_attr sysfs; char *name; int id; @@ -130,6 +131,7 @@ static int persistent_event_open(int cpu, struct pevent *pevent, if (ret) goto fail; + atomic_inc(&pevent->refcount); atomic_inc(&event->mmap_count); /* All workie, enable event now */ @@ -144,8 +146,11 @@ static int persistent_event_open(int cpu, struct pevent *pevent, static void persistent_event_close(int cpu, struct pevent *pevent) { struct perf_event *event = pevent_del(pevent, cpu); - if (event) + if (event) { + /* Safe, the caller holds &pevent->refcount too. */ + atomic_dec(&pevent->refcount); persistent_event_release(event); + } } static int pevent_sysfs_register(struct pevent *event); @@ -162,6 +167,8 @@ persistent_open(char *name, struct perf_event_attr *attr, int nr_pages) if (!pevent) return -ENOMEM; + atomic_set(&pevent->refcount, 1); + ret = get_event_id(pevent); if (ret < 0) goto fail; @@ -187,21 +194,21 @@ persistent_open(char *name, struct perf_event_attr *attr, int nr_pages) } ret = pevent_sysfs_register(pevent); - if (ret) - goto fail; - - return 0; + if (!ret) + goto out; fail: for_each_possible_cpu(cpu) persistent_event_close(cpu, pevent); - if (pevent->id) - put_event_id(pevent->id); - kfree(pevent->name); - kfree(pevent); - pr_err("%s: Error adding persistent event: %d\n", __func__, ret); +out: + if (atomic_dec_and_test(&pevent->refcount)) { + if (pevent->id) + put_event_id(pevent->id); + kfree(pevent->name); + kfree(pevent); + } return ret; } -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/