linux-kernel - [PATCH 14/14] perf evlist: Unmap ring buffer when fd is nuked

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Date:	Wed, 10 Sep 2014 11:08:49 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Jiri Olsa <jolsa@...hat.com>
Cc:	linux-kernel@...r.kernel.org,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Borislav Petkov <bp@...e.de>,
	Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Jean Pihet <jean.pihet@...aro.org>,
	Jiri Olsa <jolsa@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: [PATCH 14/14] perf evlist: Unmap ring buffer when fd is nuked

From: Arnaldo Carvalho de Melo <acme@...hat.com>

As noticed by receiving a POLLHUP for its pollfd entry.

Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: Corey Ashford <cjashfor@...ux.vnet.ibm.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Jean Pihet <jean.pihet@...aro.org>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Link: http://lkml.kernel.org/n/tip-4p3ledwt3ra9ak8e5yu3y928@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/evlist.c | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 6d2499cfd789..fdb755f6e299 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -25,6 +25,8 @@
 #include <linux/bitops.h>
 #include <linux/hash.h>
 
+static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx);
+
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
 #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
 
@@ -424,14 +426,35 @@ int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
 	return 0;
 }
 
+static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx)
+{
+	int pos = fdarray__add(&evlist->pollfd, fd, POLLIN | POLLERR | POLLHUP);
+	/*
+	 * Save the idx so that when we filter out fds POLLHUP'ed we can
+	 * close the associated evlist->mmap[] entry.
+	 */
+	if (pos >= 0)
+		evlist->pollfd.priv[pos] = idx;
+
+	return pos;
+}
+
 int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
 {
-	return fdarray__add(&evlist->pollfd, fd, POLLIN | POLLERR | POLLHUP);
+	return __perf_evlist__add_pollfd(evlist, fd, -1);
+}
+
+static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd)
+{
+	struct perf_evlist *evlist = container_of(fda, struct perf_evlist, pollfd);
+
+	perf_evlist__mmap_put(evlist, fda->priv[fd]);
 }
 
 int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
 {
-	return fdarray__filter(&evlist->pollfd, revents_and_mask, NULL);
+	return fdarray__filter(&evlist->pollfd, revents_and_mask,
+			       perf_evlist__munmap_filtered);
 }
 
 int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
@@ -751,7 +774,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
 			perf_evlist__mmap_get(evlist, idx);
 		}
 
-		if (perf_evlist__add_pollfd(evlist, fd) < 0) {
+		if (__perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
 			perf_evlist__mmap_put(evlist, idx);
 			return -1;
 		}
-- 
1.9.3

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