Merge tag 'perf-core-for-mingo-20160510' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

- Recording 'dwarf' callchains do not need DWARF unwinding support (He Kuang)

- Print recently added perf_event_attr.write_backward bit flag in -vv
  verbose mode (Arnaldo Carvalho de Melo)

- Fix incorrect python db-export error message in 'perf script' (Chris Phlipot)

- Fix handling of zero-length symbols (Chris Phlipot)

- perf stat: Scale values by unit before metrics (Andi Kleen)

Infrastructure changes:

- Rewrite strbuf not to die(), making tools using it to check its
  return value instead (Masami Hiramatsu)

- Support reading from backward ring buffer, add a 'perf test' entry
  for it (Wang Nan)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 10 insertions, 8 deletions

diff --git a/tools/perf/builtin-help.c b/tools/perf/builtin-help.c
index bc1de9b8fd67..f9830c902b78 100644
--- a/tools/perf/builtin-help.c
+++ b/tools/perf/builtin-help.c
@@ -61,6 +61,7 @@ static int check_emacsclient_version(void)
         struct child_process ec_process;
         const char *argv_ec[] = { "emacsclient", "--version", NULL };
         int version;
+        int ret = -1;
 
         /* emacsclient prints its version number on stderr */
         memset(&ec_process, 0, sizeof(ec_process));
@@ -71,7 +72,10 @@ static int check_emacsclient_version(void)
                 fprintf(stderr, "Failed to start emacsclient.\n");
                 return -1;
         }
-        strbuf_read(&buffer, ec_process.err, 20);
+        if (strbuf_read(&buffer, ec_process.err, 20) < 0) {
+                fprintf(stderr, "Failed to read emacsclient version\n");
+                goto out;
+        }
         close(ec_process.err);
 
         /*
@@ -82,8 +86,7 @@ static int check_emacsclient_version(void)
 
         if (prefixcmp(buffer.buf, "emacsclient")) {
                 fprintf(stderr, "Failed to parse emacsclient version.\n");
-                strbuf_release(&buffer);
-                return -1;
+                goto out;
         }
 
         version = atoi(buffer.buf + strlen("emacsclient"));
@@ -92,12 +95,11 @@ static int check_emacsclient_version(void)
                 fprintf(stderr,
                         "emacsclient version '%d' too old (< 22).\n",
                         version);
-                strbuf_release(&buffer);
-                return -1;
-        }
-
+        } else
+                ret = 0;
+out:
         strbuf_release(&buffer);
-        return 0;
+        return ret;
 }
 
 static void exec_woman_emacs(const char *path, const char *page)