tracing: Add string_has_prefix() and usages

From: "Steven Rostedt (VMware)" <[email protected]>

The tracing histogram code contains a lot of instances of the construct:

strncmp(str, "const", sizeof("const") - 1)

This can be prone to bugs due to typos or bad cut and paste. Use the str_has_prefix() helper macro instead that removes the need for having two copies of the constant string.

Cc Tom Zanussi <[email protected]>

Signed-off-by Steven Rostedt (VMware) <[email protected]>

---
 kernel/trace/trace_events_hist.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

kernel/trace/trace_events_hist.c +14 -14

index c5448c103770..9d590138f870 100644
@@ -1881,8 +1881,8 @@ static int parse_action(char *str, struct hist_trigger_attrs *attrs)
 	if (attrs->n_actions >= HIST_ACTIONS_MAX)
 		return ret;
 
-	if ((strncmp(str, "onmatch(", sizeof("onmatch(") - 1) = 0) ||
-	    (strncmp(str, "onmax(", sizeof("onmax(") - 1) = 0)) {
+	if ((str_has_prefix(str, "onmatch(")) ||
+	    (str_has_prefix(str, "onmax("))) {
 		attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
 		if (!attrs->action_str[attrs->n_actions]) {
 			ret = -ENOMEM;

@@ -1899,34 +1899,34 @@ static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
 {
 	int ret = 0;
 
-	if ((strncmp(str, "key=", sizeof("key=") - 1) = 0) ||
-	    (strncmp(str, "keys=", sizeof("keys=") - 1) = 0)) {
+	if ((str_has_prefix(str, "key=")) ||
+	    (str_has_prefix(str, "keys="))) {
 		attrs->keys_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->keys_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if ((strncmp(str, "val=", sizeof("val=") - 1) = 0) ||
-		 (strncmp(str, "vals=", sizeof("vals=") - 1) = 0) ||
-		 (strncmp(str, "values=", sizeof("values=") - 1) = 0)) {
+	} else if ((str_has_prefix(str, "val=")) ||
+		   (str_has_prefix(str, "vals=")) ||
+		   (str_has_prefix(str, "values="))) {
 		attrs->vals_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->vals_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "sort=", sizeof("sort=") - 1) = 0) {
+	} else if (str_has_prefix(str, "sort=")) {
 		attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->sort_key_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "name=", sizeof("name=") - 1) = 0) {
+	} else if (str_has_prefix(str, "name=")) {
 		attrs->name = kstrdup(str, GFP_KERNEL);
 		if (!attrs->name) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "clock=", sizeof("clock=") - 1) = 0) {
+	} else if (str_has_prefix(str, "clock=")) {
 		strsep(&str, "=");
 		if (!str) {
 			ret = -EINVAL;

@@ -1939,7 +1939,7 @@ static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "size=", sizeof("size=") - 1) = 0) {
+	} else if (str_has_prefix(str, "size=")) {
 		int map_bits = parse_map_size(str);
 
 		if (map_bits < 0) {

@@ -3558,7 +3558,7 @@ static struct action_data *onmax_parse(char *str)
 	if (!onmax_fn_name || !str)
 		goto free;
 
-	if (strncmp(onmax_fn_name, "save", sizeof("save") - 1) = 0) {
+	if (str_has_prefix(onmax_fn_name, "save")) {
 		char *params = strsep(&str, ")");
 
 		if (!params) {

@@ -4346,7 +4346,7 @@ static int parse_actions(struct hist_trigger_data *hist_data)
 	for (i = 0; i < hist_data->attrs->n_actions; i++) {
 		str = hist_data->attrs->action_str[i];
 
-		if (strncmp(str, "onmatch(", sizeof("onmatch(") - 1) = 0) {
+		if (str_has_prefix(str, "onmatch(")) {
 			char *action_str = str + sizeof("onmatch(") - 1;
 
 			data = onmatch_parse(tr, action_str);

@@ -4355,7 +4355,7 @@ static int parse_actions(struct hist_trigger_data *hist_data)
 				break;
 			}
 			data->fn = action_trace;
-		} else if (strncmp(str, "onmax(", sizeof("onmax(") - 1) = 0) {
+		} else if (str_has_prefix(str, "onmax(")) {
 			char *action_str = str + sizeof("onmax(") - 1;
 
 			data = onmax_parse(action_str);

Quoted 1 line

Cc Tom Zanussi <[email protected]>

I have no idea why I copied your intel email. The linux.intel.com appears to be no longer active. I'm going to rebase to fix this email address.

Quoted 13 lines · On Sat, 22 Dec 2018 11:20:09 -0500 Steven Rostedt <[email protected]> wrote:

From: "Steven Rostedt (VMware)" <[email protected]>

The tracing histogram code contains a lot of instances of the construct:

strncmp(str, "const", sizeof("const") - 1)

This can be prone to bugs due to typos or bad cut and paste. Use the
str_has_prefix() helper macro instead that removes the need for having two
copies of the constant string.

Quoted 1 line

Cc Tom Zanussi <[email protected]>

I have no idea why I copied your intel email. The linux.intel.com appears to be no longer active. I'm going to rebase to fix this email address.

-- Steve

Quoted 120 lines

Signed-off-by Steven Rostedt (VMware) <[email protected]>

---
 kernel/trace/trace_events_hist.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

kernel/trace/trace_events_hist.c +0 -1

index c5448c103770..9d590138f870 100644
@@ -1881,8 +1881,8 @@ static int parse_action(char *str, struct
 hist_trigger_attrs *attrs)
 	if (attrs->n_actions >= HIST_ACTIONS_MAX)
 		return ret;
 
-	if ((strncmp(str, "onmatch(", sizeof("onmatch(") - 1) =

0) ||

kernel/trace/trace_events_hist.c +2 -1

-	    (strncmp(str, "onmax(", sizeof("onmax(") - 1) = 0)) {
+	if ((str_has_prefix(str, "onmatch(")) ||
+	    (str_has_prefix(str, "onmax("))) {
 		attrs->action_str[attrs->n_actions] = kstrdup(str,

GFP_KERNEL);

kernel/trace/trace_events_hist.c +2 -3

 		if (!attrs->action_str[attrs->n_actions]) {
 			ret = -ENOMEM;

@@ -1899,34 +1899,34 @@ static int parse_assignment(char *str,
 struct hist_trigger_attrs *attrs)
 {
 	int ret = 0;
 
-	if ((strncmp(str, "key=", sizeof("key=") - 1) = 0) ||
-	    (strncmp(str, "keys=", sizeof("keys=") - 1) = 0)) {
+	if ((str_has_prefix(str, "key=")) ||
+	    (str_has_prefix(str, "keys="))) {
 		attrs->keys_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->keys_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if ((strncmp(str, "val=", sizeof("val=") - 1) = 0)

||

kernel/trace/trace_events_hist.c +0 -1

-		 (strncmp(str, "vals=", sizeof("vals=") - 1) = 0)

||

kernel/trace/trace_events_hist.c +0 -1

-		 (strncmp(str, "values=", sizeof("values=") - 1)

= 0)) {

kernel/trace/trace_events_hist.c +3 -1

+	} else if ((str_has_prefix(str, "val=")) ||
+		   (str_has_prefix(str, "vals=")) ||
+		   (str_has_prefix(str, "values="))) {
 		attrs->vals_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->vals_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "sort=", sizeof("sort=") - 1) =

0) {

kernel/trace/trace_events_hist.c +1 -1

+	} else if (str_has_prefix(str, "sort=")) {
 		attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->sort_key_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "name=", sizeof("name=") - 1) =

0) {

kernel/trace/trace_events_hist.c +1 -1

+	} else if (str_has_prefix(str, "name=")) {
 		attrs->name = kstrdup(str, GFP_KERNEL);
 		if (!attrs->name) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "clock=", sizeof("clock=") - 1) =

0) {

kernel/trace/trace_events_hist.c +2 -1

+	} else if (str_has_prefix(str, "clock=")) {
 		strsep(&str, "=");
 		if (!str) {
 			ret = -EINVAL;

@@ -1939,7 +1939,7 @@ static int parse_assignment(char *str, struct
 hist_trigger_attrs *attrs)
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "size=", sizeof("size=") - 1) =
 0) {
+	} else if (str_has_prefix(str, "size=")) {
 		int map_bits = parse_map_size(str);

kernel/trace/trace_events_hist.c +1 -1

 		if (map_bits < 0) {

@@ -3558,7 +3558,7 @@ static struct action_data *onmax_parse(char
 *str)
 	if (!onmax_fn_name || !str)
 		goto free;
 
-	if (strncmp(onmax_fn_name, "save", sizeof("save") - 1) =
 0) {
+	if (str_has_prefix(onmax_fn_name, "save")) {
 		char *params = strsep(&str, ")");

kernel/trace/trace_events_hist.c +1 -1

 		if (!params) {

@@ -4346,7 +4346,7 @@ static int parse_actions(struct
 hist_trigger_data *hist_data)
 	for (i = 0; i < hist_data->attrs->n_actions; i++) {
 		str = hist_data->attrs->action_str[i];
 
-		if (strncmp(str, "onmatch(", sizeof("onmatch(") -
 1) = 0) {
+		if (str_has_prefix(str, "onmatch(")) {
 			char *action_str = str +

sizeof("onmatch(") - 1;

kernel/trace/trace_events_hist.c +1 -3

 			data = onmatch_parse(tr, action_str);

@@ -4355,7 +4355,7 @@ static int parse_actions(struct
 hist_trigger_data *hist_data)
 				break;
 			}
 			data->fn = action_trace;
-		} else if (strncmp(str, "onmax(", sizeof("onmax(")
- 1) = 0) {
+		} else if (str_has_prefix(str, "onmax(")) {
 			char *action_str = str + sizeof("onmax(")
- 1;
 
 			data = onmax_parse(action_str);

Hi Steve,

Quoted 18 lines · Steven Rostedt

Quoted 14 lines · On Sat, 22 Dec 2018 11:20:09 -0500 Steven Rostedt <[email protected]> wrote:

From: "Steven Rostedt (VMware)" <[email protected]>

The tracing histogram code contains a lot of instances of the construct:

strncmp(str, "const", sizeof("const") - 1)

This can be prone to bugs due to typos or bad cut and paste. Use the
str_has_prefix() helper macro instead that removes the need for having two
copies of the constant string.

Cc Tom Zanussi <[email protected]>

Quoted 3 lines

I have no idea why I copied your intel email. The linux.intel.com appears to be no longer active. I'm going to rebase to fix this email address.

linux.intel.com is active, but there's no zanussi there, just tom.zanussi ;-)

So [email protected] should work fine.

Quoted 27 lines · On Sat, 22 Dec 2018 12:03:41 -0600 Tom Zanussi <[email protected]> wrote:

Hi Steve,

Quoted 23 lines · Steven Rostedt

Quoted 7 lines · On Sat, 22 Dec 2018 11:20:09 -0500 Steven Rostedt <[email protected]> wrote:

From: "Steven Rostedt (VMware)" <[email protected]>

The tracing histogram code contains a lot of instances of the construct:

strncmp(str, "const", sizeof("const") - 1)

Quoted 8 lines

This can be prone to bugs due to typos or bad cut and paste. Use
the
str_has_prefix() helper macro instead that removes the need for having two
copies of the constant string.

Cc Tom Zanussi <[email protected]>

I have no idea why I copied your intel email. The linux.intel.com appears to be no longer active. I'm going to rebase to fix this email
address.

Quoted 4 lines

linux.intel.com is active, but there's no zanussi there, just tom.zanussi ;-)

So [email protected] should work fine.

BTW, would you give me your ack-by?

-- Steve

From: "Steven Rostedt (VMware)" <[email protected]>

The tracing histogram code contains a lot of instances of the construct:

strncmp(str, "const", sizeof("const") - 1)

This can be prone to bugs due to typos or bad cut and paste. Use the str_has_prefix() helper macro instead that removes the need for having two copies of the constant string.

Cc Tom Zanussi <[email protected]>

Signed-off-by Steven Rostedt (VMware) <[email protected]>

---
 kernel/trace/trace_events_hist.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

kernel/trace/trace_events_hist.c +12 -12

index c5448c103770..9d590138f870 100644
@@ -1881,8 +1881,8 @@ static int parse_action(char *str, struct hist_trigger_attrs *attrs)
 	if (attrs->n_actions >= HIST_ACTIONS_MAX)
 		return ret;
 
-	if ((strncmp(str, "onmatch(", sizeof("onmatch(") - 1) = 0) ||
-	    (strncmp(str, "onmax(", sizeof("onmax(") - 1) = 0)) {
+	if ((str_has_prefix(str, "onmatch(")) ||
+	    (str_has_prefix(str, "onmax("))) {
 		attrs->action_str[attrs->n_actions] = kstrdup(str, GFP_KERNEL);
 		if (!attrs->action_str[attrs->n_actions]) {
 			ret = -ENOMEM;

@@ -1899,34 +1899,34 @@ static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
 {
 	int ret = 0;
 
-	if ((strncmp(str, "key=", sizeof("key=") - 1) = 0) ||
-	    (strncmp(str, "keys=", sizeof("keys=") - 1) = 0)) {
+	if ((str_has_prefix(str, "key=")) ||
+	    (str_has_prefix(str, "keys="))) {
 		attrs->keys_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->keys_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if ((strncmp(str, "val=", sizeof("val=") - 1) = 0) ||
-		 (strncmp(str, "vals=", sizeof("vals=") - 1) = 0) ||
-		 (strncmp(str, "values=", sizeof("values=") - 1) = 0)) {
+	} else if ((str_has_prefix(str, "val=")) ||
+		   (str_has_prefix(str, "vals=")) ||
+		   (str_has_prefix(str, "values="))) {
 		attrs->vals_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->vals_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "sort=", sizeof("sort=") - 1) = 0) {
+	} else if (str_has_prefix(str, "sort=")) {
 		attrs->sort_key_str = kstrdup(str, GFP_KERNEL);
 		if (!attrs->sort_key_str) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "name=", sizeof("name=") - 1) = 0) {
+	} else if (str_has_prefix(str, "name=")) {
 		attrs->name = kstrdup(str, GFP_KERNEL);
 		if (!attrs->name) {
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "clock=", sizeof("clock=") - 1) = 0) {
+	} else if (str_has_prefix(str, "clock=")) {
 		strsep(&str, "=");
 		if (!str) {
 			ret = -EINVAL;

@@ -1939,7 +1939,7 @@ static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
 			ret = -ENOMEM;
 			goto out;
 		}
-	} else if (strncmp(str, "size=", sizeof("size=") - 1) = 0) {
+	} else if (str_has_prefix(str, "size=")) {
 		int map_bits = parse_map_size(str);
 
 		if (map_bits < 0) {

@@ -3558,7 +3558,7 @@ static struct action_data *onmax_parse(char *str)
 	if (!onmax_fn_name || !str)
 		goto free;
 
-	if (strncmp(onmax_fn_name, "save", sizeof("save") - 1) = 0) {
+	if (str_has_prefix(onmax_fn_name, "save")) {
 		char *params = strsep(&str, ")");
 
 		if (!params) {

kernel/trace/trace_events_hist.c +0 -0

 			data = onmax_parse(action_str);

Signature · 1 line

2.19.2

From: "Steven Rostedt (VMware)" <[email protected]>

As str_has_prefix() returns the length on match, we can use that for the updating of the string pointer instead of recalculating the prefix size.

Cc Tom Zanussi <[email protected]>

Signed-off-by Steven Rostedt (VMware) <[email protected]>

---
 kernel/trace/trace_events_hist.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

kernel/trace/trace_events_hist.c +0 -0

index 0d878dcd1e4b..449d90cfa151 100644
@@ -4342,12 +4342,13 @@ static int parse_actions(struct hist_trigger_data *hist_data)
 	unsigned int i;
 	int ret = 0;

kernel/trace/trace_events_hist.c +2 -2

 			data = onmatch_parse(tr, action_str);
 			if (IS_ERR(data)) {

@@ -4355,8 +4356,8 @@ static int parse_actions(struct hist_trigger_data *hist_data)
 				break;
 			}
 			data->fn = action_trace;
-		} else if (str_has_prefix(str, "onmax(")) {
-			char *action_str = str + sizeof("onmax(") - 1;
+		} else if ((len = str_has_prefix(str, "onmax("))) {
+			char *action_str = str + len;
 
 			data = onmax_parse(action_str);
 			if (IS_ERR(data)) {

Signature · 1 line

2.19.2

From: "Steven Rostedt (VMware)" <[email protected]>

As str_has_prefix() returns the length on match, we can use that for the
updating of the string pointer instead of recalculating the prefix size.

Cc Tom Zanussi <[email protected]>

Signed-off-by Steven Rostedt (VMware) <[email protected]>

---
 kernel/trace/trace_events_hist.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

kernel/trace/trace_events_hist.c +5 -5

index 0d878dcd1e4b..449d90cfa151 100644
@@ -4342,12 +4342,13 @@ static int parse_actions(struct
 hist_trigger_data *hist_data)
 	unsigned int i;
 	int ret = 0;
 	char *str;
+	int len;
 
 	for (i = 0; i < hist_data->attrs->n_actions; i++) {
 		str = hist_data->attrs->action_str[i];
 
-		if (str_has_prefix(str, "onmatch(")) {
-			char *action_str = str + sizeof("onmatch(")
- 1;
+		if ((len = str_has_prefix(str, "onmatch("))) {
+			char *action_str = str + len;
 
 			data = onmatch_parse(tr, action_str);
 			if (IS_ERR(data)) {

@@ -4355,8 +4356,8 @@ static int parse_actions(struct
 hist_trigger_data *hist_data)
 				break;
 			}
 			data->fn = action_trace;
-		} else if (str_has_prefix(str, "onmax(")) {
-			char *action_str = str + sizeof("onmax(") -
 1;
+		} else if ((len = str_has_prefix(str, "onmax("))) {
+			char *action_str = str + len;
 

From: "Steven Rostedt (VMware)" <[email protected]>

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 <[email protected]>

Cc Masami Hiramatsu <[email protected]>

Signed-off-by Steven Rostedt (VMware) <[email protected]>

---
 kernel/trace/trace.c       |  8 +++++---
 kernel/trace/trace_probe.c | 17 +++++++++--------
 kernel/trace/trace_stack.c |  6 ++++--
 3 files changed, 18 insertions(+), 13 deletions(-)

kernel/trace/trace.c +5 -3

index eac2824a18ab..18b86c3974e1 100644
@@ -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);
 

kernel/trace/trace_probe.c +9 -8

index 541375737403..9962cb5da8ac 100644
@@ -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;

kernel/trace/trace_stack.c +4 -2

index 3641f28c343f..eec648a0d673 100644
@@ -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;

Signature · 1 line

2.19.2

Quoted 8 lines · On Sat, 22 Dec 2018 11:20:12 -0500 Steven Rostedt <[email protected]> wrote:

From: "Steven Rostedt (VMware)" <[email protected]>

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.

Looks good to me.

Acked-by Masami Hiramatsu <[email protected]>

for trace_probe part.

They ran through all my tests, althought zero-day-bot had a weird build regression in sh, that looks totally unrelated:

Regressions in current branch:

arch/sh/kernel/dwarf.c:107:26: error: 'dwarf_frame_reg' defined but not used [-Werror=unused-function] arch/sh/kernel/dwarf.c:1209:0: error: unterminated argument list invoking macro "WARN_ON" arch/sh/kernel/dwarf.c:226:12: error: 'dwarf_read_encoded_value' defined but not used [-Werror=unused-function] arch/sh/kernel/dwarf.c:306:26: error: 'dwarf_lookup_cie' defined but not used [-Werror=unused-function] arch/sh/kernel/dwarf.c:38:27: error: 'dwarf_frame_cachep' defined but not used [-Werror=unused-variable] arch/sh/kernel/dwarf.c:399:12: error: 'dwarf_cfa_execute_insns' defined but not used [-Werror=unused-function] arch/sh/kernel/dwarf.c:41:27: error: 'dwarf_reg_cachep' defined but not used [-Werror=unused-variable] arch/sh/kernel/dwarf.c:580:22: error: unused variable 'frame' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:581:20: error: unused variable 'cie' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:582:20: error: unused variable 'fde' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:583:20: error: unused variable 'reg' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:584:16: error: unused variable 'addr' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:622:3: error: expected ';' at end of input arch/sh/kernel/dwarf.c:622:3: error: expected declaration or statement at end of input arch/sh/kernel/dwarf.c:622:3: error: 'WARN_ON' undeclared (first use in this function); did you mean 'WMARK_LOW'?

Pushing to my for-next branch should kick off another run. Let's see if it reports that again. Unless someone knows why that happened?

I hope everyone is OK with these changes. I pushed to linux-next but I'm willing to change them if there are still issues.

They ran through all my tests, althought zero-day-bot had a weird build regression in sh, that looks totally unrelated:

Regressions in current branch:

arch/sh/kernel/dwarf.c:107:26: error: 'dwarf_frame_reg' defined but not used [-Werror=unused-function] arch/sh/kernel/dwarf.c:1209:0: error: unterminated argument list invoking macro "WARN_ON" arch/sh/kernel/dwarf.c:226:12: error: 'dwarf_read_encoded_value' defined but not used [-Werror=unused-function] arch/sh/kernel/dwarf.c:306:26: error: 'dwarf_lookup_cie' defined but not used [-Werror=unused-function] arch/sh/kernel/dwarf.c:38:27: error: 'dwarf_frame_cachep' defined but not used [-Werror=unused-variable] arch/sh/kernel/dwarf.c:399:12: error: 'dwarf_cfa_execute_insns' defined but not used [-Werror=unused-function] arch/sh/kernel/dwarf.c:41:27: error: 'dwarf_reg_cachep' defined but not used [-Werror=unused-variable] arch/sh/kernel/dwarf.c:580:22: error: unused variable 'frame' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:581:20: error: unused variable 'cie' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:582:20: error: unused variable 'fde' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:583:20: error: unused variable 'reg' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:584:16: error: unused variable 'addr' [-Werror=unused-variable] arch/sh/kernel/dwarf.c:622:3: error: expected ';' at end of input arch/sh/kernel/dwarf.c:622:3: error: expected declaration or statement at end of input arch/sh/kernel/dwarf.c:622:3: error: 'WARN_ON' undeclared (first use in this function); did you mean 'WMARK_LOW'?

Pushing to my for-next branch should kick off another run. Let's see if it reports that again. Unless someone knows why that happened?

git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: 92b9de3e574bd874188a4e27a8830bb901a08ef8

Steven Rostedt (VMware) (5):
string.h: Add str_has_prefix() helper function
tracing: Use str_has_prefix() helper for histogram code
tracing: Use str_has_prefix() instead of using fixed sizes
tracing: Have the historgram use the result of str_has_prefix() for len of prefix
tracing: Use the return of str_has_prefix() to remove open coded numbers

----

 include/linux/string.h           | 20 ++++++++++++++++++++
 kernel/trace/trace.c             |  8 +++++---
 kernel/trace/trace_events.c      |  2 +-
 kernel/trace/trace_events_hist.c | 35 ++++++++++++++++++-----------------
 kernel/trace/trace_probe.c       | 17 +++++++++--------
 kernel/trace/trace_stack.c       |  6 ++++--
 6 files changed, 57 insertions(+), 31 deletions(-)

Quoted 6 lines

Steven Rostedt (VMware) (5):
string.h: Add str_has_prefix() helper function
tracing: Use str_has_prefix() helper for histogram code
tracing: Use str_has_prefix() instead of using fixed sizes
tracing: Have the historgram use the result of str_has_prefix() for len of prefix
tracing: Use the return of str_has_prefix() to remove open coded numbers

For the series:

Acked-by Namhyung Kim <[email protected]>