perf/live-mode: Handle payload-less events
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>
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@ -696,15 +696,18 @@ more:
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p = &event;
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p += sizeof(struct perf_event_header);
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err = do_read(self->fd, p, size - sizeof(struct perf_event_header));
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if (err <= 0) {
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if (err == 0) {
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pr_err("unexpected end of event stream\n");
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goto done;
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}
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if (size - sizeof(struct perf_event_header)) {
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err = do_read(self->fd, p,
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size - sizeof(struct perf_event_header));
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if (err <= 0) {
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if (err == 0) {
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pr_err("unexpected end of event stream\n");
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goto done;
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}
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pr_err("failed to read event data\n");
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goto out_err;
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pr_err("failed to read event data\n");
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goto out_err;
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}
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}
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if (size == 0 ||
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