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authorJiri Olsa <jolsa@redhat.com>2009-10-23 19:36:17 -0400
committerIngo Molnar <mingo@elte.hu>2009-10-24 11:07:50 +0200
commit3e69533b51930a7169235db2caf703884e6e3bbb (patch)
tree4cd0fe383dcb9eab2b0f944f227caffa3cdcd209
parentcf8517cf905b5cd31d5790250b9ac39f7cb8aa53 (diff)
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.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index ed17565826b..b6c12c6a1bc 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);