tracing: Use str_has_prefix() instead of using fixed sizes

There are several instances of strncmp(str, "const", 123), where 123 is the
strlen of the const string to check if "const" is the prefix of str. But
this can be error prone. Use str_has_prefix() instead.

Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 5afcfec..eac2824 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4411,7 +4411,7 @@ static int trace_set_options(struct trace_array *tr, char *option)
 
        cmp = strstrip(option);
 
-       if (strncmp(cmp, "no", 2) == 0) {
+       if (str_has_prefix(cmp, "no")) {
                neg = 1;
                cmp += 2;
        }

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index bd0162c..5b3b0c3 100644 (file)
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1251,7 +1251,7 @@ static int f_show(struct seq_file *m, void *v)
         */
        array_descriptor = strchr(field->type, '[');
 
-       if (!strncmp(field->type, "__data_loc", 10))
+       if (str_has_prefix(field->type, "__data_loc"))
                array_descriptor = NULL;
 
        if (!array_descriptor)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 9d59013..0d878dc 100644 (file)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -518,7 +518,7 @@ static int synth_event_define_fields(struct trace_event_call *call)
 
 static bool synth_field_signed(char *type)
 {
-       if (strncmp(type, "u", 1) == 0)
+       if (str_has_prefix(type, "u"))
                return false;
 
        return true;

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index ff86417..5413757 100644 (file)
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -194,7 +194,7 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
                        code->op = FETCH_OP_RETVAL;
                else
                        ret = -EINVAL;
-       } else if (strncmp(arg, "stack", 5) == 0) {
+       } else if (str_has_prefix(arg, "stack")) {
                if (arg[5] == '\0') {
                        code->op = FETCH_OP_STACKP;
                } else if (isdigit(arg[5])) {
@@ -213,7 +213,7 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
        } else if (((flags & TPARG_FL_MASK) ==
                    (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
-                  strncmp(arg, "arg", 3) == 0) {
+                  str_has_prefix(arg, "arg")) {
                if (!isdigit(arg[3]))
                        return -EINVAL;
                ret = kstrtoul(arg + 3, 10, &param);

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index e2a153f..3641f28 100644 (file)
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -448,7 +448,7 @@ static char stack_trace_filter_buf[COMMAND_LINE_SIZE+1] __initdata;
 
 static __init int enable_stacktrace(char *str)
 {
-       if (strncmp(str, "_filter=", 8) == 0)
+       if (str_has_prefix(str, "_filter="))
                strncpy(stack_trace_filter_buf, str+8, COMMAND_LINE_SIZE);
 
        stack_tracer_enabled = 1;