Messages in this thread Patch in this message | | | Date | Fri, 23 Oct 2009 19:36:17 -0400 | From | Steven Rostedt <> | Subject | [PATCH 2/4] [PATCH 2/4] tracing: fix trace_seq_printf return value |
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From: Jiri Olsa <jolsa@redhat.com>
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.
Making trace_seq_printf return 0 if the trace oversizes the buffer's free space, 1 otherwise.
Signed-off-by: Jiri Olsa <jolsa@redhat.com> LKML-Reference: <20091022120958.GB2311@jolsa.redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- 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); -- 1.6.3.3
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