tools include: Adopt strstarts() from the kernel

Replacing prefixcmp(), same purpose, inverted result, so standardize on
the kernel variant, to reduce silly differences among tools/ and the
kernel sources, making it easier for people to work in both codebases.

And then doing:

	if (strstarts(option, "no-"))

Looks clearer than doing:

	if (!prefixcmp(option, "no-"))

To figure out if option starts witn "no-".

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-kaei42gi7lpa8subwtv7eug8@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 10 insertions, 9 deletions

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 4bd2d1d882af..4a1264c66101 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -1246,7 +1246,7 @@ int bpf__config_obj(struct bpf_object *obj,
 	if (!obj || !term || !term->config)
 		return -EINVAL;
 
-	if (!prefixcmp(term->config, "map:")) {
+	if (strstarts(term->config, "map:")) {
 		key_scan_pos = sizeof("map:") - 1;
 		err = bpf__obj_config_map(obj, term, evlist, &key_scan_pos);
 		goto out;
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 22d413ae6025..02130e2e72c7 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -304,7 +304,7 @@ int perf_callchain_config(const char *var, const char *value)
 {
 	char *endptr;
 
-	if (prefixcmp(var, "call-graph."))
+	if (!strstarts(var, "call-graph."))
 		return 0;
 	var += sizeof("call-graph.") - 1;
 
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 31a7dea248d0..bc75596f9e79 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -19,6 +19,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <linux/string.h>
 
 #include "sane_ctype.h"
 
@@ -433,22 +434,22 @@ static int perf_ui_config(const char *var, const char *value)
 int perf_default_config(const char *var, const char *value,
 			void *dummy __maybe_unused)
 {
-	if (!prefixcmp(var, "core."))
+	if (strstarts(var, "core."))
 		return perf_default_core_config(var, value);
 
-	if (!prefixcmp(var, "hist."))
+	if (strstarts(var, "hist."))
 		return perf_hist_config(var, value);
 
-	if (!prefixcmp(var, "ui."))
+	if (strstarts(var, "ui."))
 		return perf_ui_config(var, value);
 
-	if (!prefixcmp(var, "call-graph."))
+	if (strstarts(var, "call-graph."))
 		return perf_callchain_config(var, value);
 
-	if (!prefixcmp(var, "llvm."))
+	if (strstarts(var, "llvm."))
 		return perf_llvm_config(var, value);
 
-	if (!prefixcmp(var, "buildid."))
+	if (strstarts(var, "buildid."))
 		return perf_buildid_config(var, value);
 
 	/* Add other config variables here. */
diff --git a/tools/perf/util/llvm-utils.c b/tools/perf/util/llvm-utils.c
index c6a15f204c03..209b0c82eff4 100644
--- a/tools/perf/util/llvm-utils.c
+++ b/tools/perf/util/llvm-utils.c
@@ -33,7 +33,7 @@ struct llvm_param llvm_param = {
 
 int perf_llvm_config(const char *var, const char *value)
 {
-	if (prefixcmp(var, "llvm."))
+	if (!strstarts(var, "llvm."))
 		return 0;
 	var += sizeof("llvm.") - 1;