The following commit has been merged in the linux branch: commit 3e69533b51930a7169235db2caf703884e6e3bbb Author: Jiri Olsa jolsa@redhat.com Date: Fri Oct 23 19:36:17 2009 -0400

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

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);