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perf/live-mode: Handle payload-less events

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Some events, such as the PERF_RECORD_FINISHED_ROUND event consist of
only an event header and no data.  In this case, a 0-length payload
will be read, and the 0 return value will be wrongly interpreted as an
'unexpected end of event stream'.

This patch allows for proper handling of data-less events by skipping
0-length reads.

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <1273038527.6383.51.camel@tropicana>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Tom Zanussi 2010-05-05 00:27:40 -05:00 committed by Frederic Weisbecker
parent 2c193c7368
commit 794e43b56c
1 changed files with 11 additions and 8 deletions
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19
tools/perf/util/session.c
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@ -696,15 +696,18 @@ more:
p = &event;
p += sizeof(struct perf_event_header);
err = do_read(self->fd, p, size - sizeof(struct perf_event_header));
if (err <= 0) {
if (err == 0) {
pr_err("unexpected end of event stream\n");
goto done;
}
if (size - sizeof(struct perf_event_header)) {
err = do_read(self->fd, p,
size - sizeof(struct perf_event_header));
if (err <= 0) {
if (err == 0) {
pr_err("unexpected end of event stream\n");
goto done;
}
pr_err("failed to read event data\n");
goto out_err;
pr_err("failed to read event data\n");
goto out_err;
}
}
if (size == 0 ||