tree-wide: add FORMAT_TIMESPAN()

src/basic/efivars.c

@@ -120,13 +120,10 @@ int efi_get_variable(
                 n = st.st_size - 4;
 
         if (DEBUG_LOGGING) {
-                char ts[FORMAT_TIMESPAN_MAX];
-                usec_t end;
-
-                end = now(CLOCK_MONOTONIC);
+                usec_t end = now(CLOCK_MONOTONIC);
                 if (end > begin + EFI_RETRY_DELAY)
                         log_debug("Detected slow EFI variable read access on %s: %s",
-                                  variable, format_timespan(ts, sizeof(ts), end - begin, 1));
+                                  variable, FORMAT_TIMESPAN(end - begin, 1));
         }
 
         /* Note that efivarfs interestingly doesn't require ftruncate() to update an existing EFI variable

src/basic/time-util.h

@@ -129,6 +129,7 @@ static inline char* format_timestamp(char *buf, size_t l, usec_t t) {
  * see C11 §6.5.2.5, and
  * https://stackoverflow.com/questions/34880638/compound-literal-lifetime-and-if-blocks */
 #define FORMAT_TIMESTAMP(t) format_timestamp((char[FORMAT_TIMESTAMP_MAX]){}, FORMAT_TIMESTAMP_MAX, t)
+#define FORMAT_TIMESPAN(t, accuracy) format_timespan((char[FORMAT_TIMESPAN_MAX]){}, FORMAT_TIMESPAN_MAX, t, accuracy)
 
 int parse_timestamp(const char *t, usec_t *usec);