From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935226AbeBMMRF (ORCPT ); Tue, 13 Feb 2018 07:17:05 -0500 Received: from terminus.zytor.com ([198.137.202.136]:46025 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934945AbeBMMRB (ORCPT ); Tue, 13 Feb 2018 07:17:01 -0500 Date: Tue, 13 Feb 2018 04:06:34 -0800 From: tip-bot for Kan Liang Message-ID: Cc: linux-kernel@vger.kernel.org, ak@linux.intel.com, yao.jin@linux.intel.com, tglx@linutronix.de, mingo@kernel.org, acme@redhat.com, hpa@zytor.com, wangnan0@huawei.com, jolsa@kernel.org, peterz@infradead.org, kan.liang@intel.com, namhyung@kernel.org Reply-To: mingo@kernel.org, tglx@linutronix.de, yao.jin@linux.intel.com, linux-kernel@vger.kernel.org, ak@linux.intel.com, wangnan0@huawei.com, hpa@zytor.com, acme@redhat.com, peterz@infradead.org, jolsa@kernel.org, kan.liang@intel.com, namhyung@kernel.org In-Reply-To: <1516310792-208685-7-git-send-email-kan.liang@intel.com> References: <1516310792-208685-7-git-send-email-kan.liang@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf mmap: Discard 'prev' in perf_mmap__read() Git-Commit-ID: a41cf9d483fbf0a97e8b131b6a006f558fdd502d X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: a41cf9d483fbf0a97e8b131b6a006f558fdd502d Gitweb: https://git.kernel.org/tip/a41cf9d483fbf0a97e8b131b6a006f558fdd502d Author: Kan Liang AuthorDate: Thu, 18 Jan 2018 13:26:21 -0800 Committer: Arnaldo Carvalho de Melo CommitDate: Tue, 6 Feb 2018 10:11:50 -0300 perf mmap: Discard 'prev' in perf_mmap__read() The 'start' and 'prev' variables are duplicates in perf_mmap__read(). Use 'map->prev' to replace 'start' in perf_mmap__read_*(). Suggested-by: Wang Nan Signed-off-by: Kan Liang Acked-by: Jiri Olsa Cc: Andi Kleen Cc: Jin Yao Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/r/1516310792-208685-7-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mmap.c | 28 ++++++++++------------------ 1 file changed, 10 insertions(+), 18 deletions(-) diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 38fa69d..125bfda 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -22,29 +22,27 @@ size_t perf_mmap__mmap_len(struct perf_mmap *map) /* When check_messup is true, 'end' must points to a good entry */ static union perf_event *perf_mmap__read(struct perf_mmap *map, - u64 start, u64 end, u64 *prev) + u64 *startp, u64 end) { unsigned char *data = map->base + page_size; union perf_event *event = NULL; - int diff = end - start; + int diff = end - *startp; if (diff >= (int)sizeof(event->header)) { size_t size; - event = (union perf_event *)&data[start & map->mask]; + event = (union perf_event *)&data[*startp & map->mask]; size = event->header.size; - if (size < sizeof(event->header) || diff < (int)size) { - event = NULL; - goto broken_event; - } + if (size < sizeof(event->header) || diff < (int)size) + return NULL; /* * Event straddles the mmap boundary -- header should always * be inside due to u64 alignment of output. */ - if ((start & map->mask) + size != ((start + size) & map->mask)) { - unsigned int offset = start; + if ((*startp & map->mask) + size != ((*startp + size) & map->mask)) { + unsigned int offset = *startp; unsigned int len = min(sizeof(*event), size), cpy; void *dst = map->event_copy; @@ -59,20 +57,15 @@ static union perf_event *perf_mmap__read(struct perf_mmap *map, event = (union perf_event *)map->event_copy; } - start += size; + *startp += size; } -broken_event: - if (prev) - *prev = start; - return event; } union perf_event *perf_mmap__read_forward(struct perf_mmap *map) { u64 head; - u64 old = map->prev; /* * Check if event was unmapped due to a POLLHUP/POLLERR. @@ -82,13 +75,12 @@ union perf_event *perf_mmap__read_forward(struct perf_mmap *map) head = perf_mmap__read_head(map); - return perf_mmap__read(map, old, head, &map->prev); + return perf_mmap__read(map, &map->prev, head); } union perf_event *perf_mmap__read_backward(struct perf_mmap *map) { u64 head, end; - u64 start = map->prev; /* * Check if event was unmapped due to a POLLHUP/POLLERR. @@ -118,7 +110,7 @@ union perf_event *perf_mmap__read_backward(struct perf_mmap *map) else end = head + map->mask + 1; - return perf_mmap__read(map, start, end, &map->prev); + return perf_mmap__read(map, &map->prev, end); } void perf_mmap__read_catchup(struct perf_mmap *map)