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author | Jiri Olsa <jolsa@redhat.com> | 2009-10-23 19:36:17 -0400 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-10-24 11:07:50 +0200 |
commit | 3e69533b51930a7169235db2caf703884e6e3bbb (patch) | |
tree | 4cd0fe383dcb9eab2b0f944f227caffa3cdcd209 | |
parent | cf8517cf905b5cd31d5790250b9ac39f7cb8aa53 (diff) | |
download | op-kernel-dev-3e69533b51930a7169235db2caf703884e6e3bbb.zip op-kernel-dev-3e69533b51930a7169235db2caf703884e6e3bbb.tar.gz |
tracing: Fix trace_seq_printf() return value
trace_seq_printf() return value is a little ambiguous. It
currently returns the length of the space available in the
buffer. printf usually returns the amount written. This is not
adequate here, because:
trace_seq_printf(s, "");
is perfectly legal, and returning 0 would indicate that it
failed.
We can always see the amount written by looking at the before
and after values of s->len. This is not quite the same use as
printf. We only care if the string was successfully written to
the buffer or not.
Make trace_seq_printf() return 0 if the trace oversizes the
buffer's free space, 1 otherwise.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091023233646.631787612@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r-- | kernel/trace/trace_output.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index ed17565..b6c12c6 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -69,6 +69,9 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter) * @s: trace sequence descriptor * @fmt: printf format string * + * It returns 0 if the trace oversizes the buffer's free + * space, 1 otherwise. + * * The tracer may use either sequence operations or its own * copy to user routines. To simplify formating of a trace * trace_seq_printf is used to store strings into a special @@ -95,7 +98,7 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...) s->len += ret; - return len; + return 1; } EXPORT_SYMBOL_GPL(trace_seq_printf); |