bcache: trace missed reading by cache_missed

Missed reading IOs are identified by s->cache_missed, not the
s->cache_miss, so in trace_bcache_read() using trace_bcache_read
to identify whether the IO is missed or not.
Signed-off-by: Tang Junhui <tang.junhui.linux@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/bcache/request.c

@@ -850,7 +850,7 @@ static void cached_dev_read_done_bh(struct closure *cl)
 
 	bch_mark_cache_accounting(s->iop.c, s->d,
 				  !s->cache_missed, s->iop.bypass);
-	trace_bcache_read(s->orig_bio, !s->cache_miss, s->iop.bypass);
+	trace_bcache_read(s->orig_bio, !s->cache_missed, s->iop.bypass);
 
 	if (s->iop.status)
 		continue_at_nobarrier(cl, cached_dev_read_error, bcache_wq);