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    SubjectRe: [PATCH 2/4] tracing: fix trace_seq_printf return value
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    On Thu, 2009-10-22 at 00:02 +0200, Jiri Olsa wrote:
    > On Wed, Oct 21, 2009 at 12:20:35PM -0400, Steven Rostedt wrote:
    > > On Wed, 2009-10-21 at 16:36 +0200, Jiri Olsa wrote:
    > > > I believe we want to return the number of written characters,
    > > > instead of the available buffer length.
    > > >
    > > > wbr,
    > > > jirka
    > > >
    > > > Signed-off-by: Jiri Olsa <jolsa@redhat.com>
    > > > ---
    > > > kernel/trace/trace_output.c | 2 +-
    > > > 1 files changed, 1 insertions(+), 1 deletions(-)
    > > >
    > > > diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
    > > > index ed17565..e871125 100644
    > > > --- a/kernel/trace/trace_output.c
    > > > +++ b/kernel/trace/trace_output.c
    > > > @@ -95,7 +95,7 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
    > > >
    > > > s->len += ret;
    > > >
    > > > - return len;
    > > > + return ret;
    > >
    > > Actually the return value here is ambiguous. Returning len is actually
    > > safer. It probably should only return 0 (buffer not big enough to write
    > > to) or 1 (buffer is big enough).
    > >
    > > Because this should actually return non zero:
    > >
    > > trace_seq_printf(s, "");
    > >
    > > -- Steve
    > >
    > > > }
    > > > EXPORT_SYMBOL_GPL(trace_seq_printf);
    > > >
    > >
    >
    > I made the suggested fix, plus spot not used function.
    >
    > ---
    > Making trace_seq_printf return 0 if the trace oversizes the buffer's free
    > space, 1 otherwise. Removing not used trace_seq_vprintf function.

    err, I hate to remove that function. This is a utility file that is
    exported for other parts of the kernel to use. At least make that a
    separate patch.

    -- Steve




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