git grep: be careful to use mutexes only when they are initialized

diff --git a/builtin/grep.c b/builtin/grep.c
index 7d0779f6cfd60149379f957941ebef18aef735ab..88b0c8013716367cddc064ac9b24575c3c9360bd 100644 (file)
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -77,10 +77,11 @@ static pthread_mutex_t grep_mutex;
 /* Used to serialize calls to read_sha1_file. */
 static pthread_mutex_t read_sha1_mutex;
 
-#define grep_lock() pthread_mutex_lock(&grep_mutex)
-#define grep_unlock() pthread_mutex_unlock(&grep_mutex)
-#define read_sha1_lock() pthread_mutex_lock(&read_sha1_mutex)
-#define read_sha1_unlock() pthread_mutex_unlock(&read_sha1_mutex)
+#define WHEN_THREADED(x) do { if (use_threads) (x); } while (0)
+#define grep_lock() WHEN_THREADED(pthread_mutex_lock(&grep_mutex))
+#define grep_unlock() WHEN_THREADED(pthread_mutex_unlock(&grep_mutex))
+#define read_sha1_lock() WHEN_THREADED(pthread_mutex_lock(&read_sha1_mutex))
+#define read_sha1_unlock() WHEN_THREADED(pthread_mutex_unlock(&read_sha1_mutex))
 
 /* Signalled when a new work_item is added to todo. */
 static pthread_cond_t cond_add;