linux-kernel - [PATCH v2] perf: Use strcmp(str, "const") instead of strncmp(str, "const", sizeof("const"))

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Date:   Thu, 20 Dec 2018 12:28:50 -0500
From:   Steven Rostedt <rostedt@...dmis.org>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...nel.org>, Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Subject: [PATCH v2] perf: Use strcmp(str, "const") instead of strncmp(str,
 "const", sizeof("const"))

As strncmp(str, "const", sizeof("const") is exactly the same as
strcmp(str, "const") use that instead, otherwise it is confusing.

sizeof("const") includes the nul terminator ('\0') of the string
"const", and that means strncmp() will only return a match if str and
"const" are exactly the same, which is what strcmp() does.

Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
---
Changes since v1:

 - Added '[PATCH*]' in subject. Bah!

 - Noticed I didn't save the file after updating "lbr"

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 32ef7bdca1cf..6840a8f43ab8 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -258,7 +258,7 @@ int parse_callchain_record(const char *arg, struct callchain_param *param)
 
 	do {
 		/* Framepointer style */
-		if (!strncmp(name, "fp", sizeof("fp"))) {
+		if (!strcmp(name, "fp")) {
 			if (!strtok_r(NULL, ",", &saveptr)) {
 				param->record_mode = CALLCHAIN_FP;
 				ret = 0;
@@ -268,7 +268,7 @@ int parse_callchain_record(const char *arg, struct callchain_param *param)
 			break;
 
 		/* Dwarf style */
-		} else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {
+		} else if (!strcmp(name, "dwarf")) {
 			const unsigned long default_stack_dump_size = 8192;
 
 			ret = 0;
@@ -283,7 +283,7 @@ int parse_callchain_record(const char *arg, struct callchain_param *param)
 				ret = get_stack_size(tok, &size);
 				param->dump_size = size;
 			}
-		} else if (!strncmp(name, "lbr", sizeof("lbr"))) {
+		} else if (!strcmp(name, "lbr")) {
 			if (!strtok_r(NULL, ",", &saveptr)) {
 				param->record_mode = CALLCHAIN_LBR;
 				ret = 0;