BLK_TC_AHEAD      202 kernel/trace/blktrace.c #define BLK_TC_RAHEAD		BLK_TC_AHEAD
BLK_TC_AHEAD     1202 kernel/trace/blktrace.c 	if (tc & BLK_TC_AHEAD)
BLK_TC_AHEAD     1726 kernel/trace/blktrace.c 	{ BLK_TC_AHEAD,		"ahead"		},