[PATCH] blktrace: mark expected switch fall-through

[Gustavo A. R. Silva]

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warning:

kernel/trace/blktrace.c: In function âblk_trace_ioctlâ:
kernel/trace/blktrace.c:725:9: warning: this statement may fall through [-Wimplicit-fallthrough=]
   start = 1;
   ~~~~~~^~~
kernel/trace/blktrace.c:726:2: note: here
  case BLKTRACESTOP:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
 kernel/trace/blktrace.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index fac0ddf8a8e2..e1c6d79fb4cc 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -723,6 +723,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 #endif
 	case BLKTRACESTART:
 		start = 1;
+		/* fall through */
 	case BLKTRACESTOP:
 		ret = __blk_trace_startstop(q, start);
 		break;
-- 
2.20.1