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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2018-12-21 23:10:26 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-12-22 22:52:30 -0500
commit3d739c1f6156c70eb0548aa288dcfbac9e0bd162 (patch)
tree4f2ae9eccd5478a2689171c8ce2c6466d4b9c247
parent036876fa56204ae0fa59045bd6bbb2691a060633 (diff)
tracing: Use the return of str_has_prefix() to remove open coded numbers
There are several locations that compare constants to the beginning of string variables to determine what commands should be done, then the constant length is used to index into the string. This is error prone as the hard coded numbers have to match the size of the constants. Instead, use the len returned from str_has_prefix() and remove the open coded string length sizes. Cc: Joe Perches <joe@perches.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> (for trace_probe part) Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
-rw-r--r--kernel/trace/trace.c8
-rw-r--r--kernel/trace/trace_probe.c17
-rw-r--r--kernel/trace/trace_stack.c6
3 files changed, 18 insertions, 13 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index eac2824a18ab..18b86c3974e1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4408,13 +4408,15 @@ static int trace_set_options(struct trace_array *tr, char *option)
int neg = 0;
int ret;
size_t orig_len = strlen(option);
+ int len;
cmp = strstrip(option);
- if (str_has_prefix(cmp, "no")) {
+ len = str_has_prefix(cmp, "no");
+ if (len)
neg = 1;
- cmp += 2;
- }
+
+ cmp += len;
mutex_lock(&trace_types_lock);
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 541375737403..9962cb5da8ac 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -186,19 +186,20 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
static int parse_probe_vars(char *arg, const struct fetch_type *t,
struct fetch_insn *code, unsigned int flags)
{
- int ret = 0;
unsigned long param;
+ int ret = 0;
+ int len;
if (strcmp(arg, "retval") == 0) {
if (flags & TPARG_FL_RETURN)
code->op = FETCH_OP_RETVAL;
else
ret = -EINVAL;
- } else if (str_has_prefix(arg, "stack")) {
- if (arg[5] == '\0') {
+ } else if ((len = str_has_prefix(arg, "stack"))) {
+ if (arg[len] == '\0') {
code->op = FETCH_OP_STACKP;
- } else if (isdigit(arg[5])) {
- ret = kstrtoul(arg + 5, 10, &param);
+ } else if (isdigit(arg[len])) {
+ ret = kstrtoul(arg + len, 10, &param);
if (ret || ((flags & TPARG_FL_KERNEL) &&
param > PARAM_MAX_STACK))
ret = -EINVAL;
@@ -213,10 +214,10 @@ 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)) &&
- str_has_prefix(arg, "arg")) {
- if (!isdigit(arg[3]))
+ (len = str_has_prefix(arg, "arg"))) {
+ if (!isdigit(arg[len]))
return -EINVAL;
- ret = kstrtoul(arg + 3, 10, &param);
+ ret = kstrtoul(arg + len, 10, &param);
if (ret || !param || param > PARAM_MAX_STACK)
return -EINVAL;
code->op = FETCH_OP_ARG;
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 3641f28c343f..eec648a0d673 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -448,8 +448,10 @@ static char stack_trace_filter_buf[COMMAND_LINE_SIZE+1] __initdata;
static __init int enable_stacktrace(char *str)
{
- if (str_has_prefix(str, "_filter="))
- strncpy(stack_trace_filter_buf, str+8, COMMAND_LINE_SIZE);
+ int len;
+
+ if ((len = str_has_prefix(str, "_filter=")))
+ strncpy(stack_trace_filter_buf, str + len, COMMAND_LINE_SIZE);
stack_tracer_enabled = 1;
last_stack_tracer_enabled = 1;